Bence Jones Protein

The Bence-Jones protein (BJP) was described in 1962 as “free monoclonal light chains”, synthesized by a

single clone of B cells. Normal plasma cells appear to produce a slight excess of light chains, but B cell neoplasms may produce a much greater excess.

Once the mechanism of tubular reabsorption becomes saturated, BJPs are excreted in urine.

The molecular mass of BJP is quite variable; BJPs appear in urine as monomers (22 kDa), dimers (44 kDa), or low-molecular mass fragments (5–18 kDa), or show a high degree of polymerization.

Associated Diseases

The most frequent associations are with the following:

multiple myeloma,
Waldenström’s macroglobulinemia,
monoclonal light chain-related amyloidosis (AL),and
light chain deposition disease

Clinical Utility

BJP determinations are useful in the following (3):

Subjects with serum monoclonal component (MC): at diagnosis and during follow-up.
Patients suspected of having a monoclonal gammopathy, clinically or from laboratory findings as follows:

– bone pain, fatigue, recurrent infections, purpura, edema,

– unexpected hypogammaglobulinemia in adults, unexplained increased erythrocyte sedimentation rate, anemia, leukopenia, and thrombocytopenia, proteinuria

Detection

Sample

The College of American Pathologists issued guidelines defining the methods for BJP detection and quantification based on a 24-hour urine specimen.
However, 24-hour collections are cumbersome and er-ratic, and BJP is particularly prone to bacterial degradation.
The latter can be minimized by adding an antibacterial agent.
Considering these drawbacks, we recommend the use of the second morning void and expressing the concentration of BJP relative to urinary creatinine.
If the method in use is sensitive enough, the urine can be used unconcentrated; when the greatest sensitivity of BJP detection is clinically needed, urine should be concentrated.
In such case, the membrane used in the concentrating devices should have a cut-off preferably of 5 kDa and, in any case, less than 10 kDa.

Method

The chosen method should verify that the two fundamental characteristics of the LCs are present: e., that they are free and monoclonal.
Immunofixation combines an electrophoretic step to verify the molecular homogeneity of the protein with immunologic typing,it is the recommended method for BJP detection.
Antisera to KIEκ and LAMBDA LCs together with antiserum to the heavy chain (HC) of the serum monoclonal immunoglobulin should be used.
Antisera to free light chains (FLCs) are expensive; in addition, they are often nonspecific and can have low avidity.
They can be useful only if it is suspected that a BJP is co-migrating with an intact immunoglobulin.
This suspicion is raised when there is a discrepancy between the HC and the LC signal grossly in favor of the latter

Sensitivity

The indication of a detection limit for BJP can only be approximate since there is no way of obtaining an accurate quantification of the protein.
However, since the indicated amount for polyclonal LC excretion is approximately 10 mg/l, a method with a sensitivity down to this limit is suggested.
Among the sensitive stains, colloidal gold provides the highest sensitivity (1–2 mg/l); colloidal Coomassie stain can detect BJP at 10 mg/l or less

Interpretation

Using methods of high resolution and adequate sensitivity, the appearance of so-called LC ladder patterns is common.
These multiple, evenly-spaced bands have been well described and are the consequence of the excretion

of polyclonal LCs in individuals with impaired tubular reabsorption.

The pattern is typical, and an experienced eye can distinguish them from BJP; however, it may sometimes be difficult to identify a BJP band co-migrating with one of the multiple bands

Alternative approaches

Immunochemical methods (nephelometry, turbidimetry) for the quantification of FLCs in urine can be used for BJP detection as an initial screening to exclude BJP, thus reducing the number of samples to process further.However, the amount of BJP can range from a few milligrams to grams per liter, so that the assay can eas-ily fall into the antigen excess zone.
Therefore, it is mandatory to control and avoid antigen excess and to document a detection limit below 10 mg/l.
A positive test should be followed by immunofixation (IF) for the following reasons:
- If the antisera used in the immunochemical method are against LCs (free and bound) it is necessary to document that the LCs are free;
- Since FLC antiserum is incapable of distinguishing monoclonal from polyclonal LCs it is necessary to define the clonality. Although in LC multiple myeloma the synthesis of polyclonal LCs is usually depressed, in several other clinically important instances (AL, LCDDs) the concentration of polyclonal FLCs in urine can be significant and variable in the course of the disease;
- IF is presently recommended to define the response to high-dose chemotherapy in multiple myeloma. It has been shown that patients achieving a negative IF have the best prognosis; accordingly, therapeutic strategies are presently designed to achieve negative IF.
The cost-benefit ratio of screening samples for BJP using quantitative immunochemical methods should be carefully evaluated depending on the type of population to be examined and the analytical performance of the immunochemical method used.

Tests to be discouraged

Methods for measuring total proteins in urine (both precipitating and dye-binding) are insensitive and not accurate for detecting BJP.
Dipsticks used to screen for protein in the standard urine examination are impregnated with a buffered dye which is sensitive mainly to albumin and can completely miss the presence of BJP.
The unreliable heat test is mentioned only because of its historical value since not all BJP precipitate upon heating.

Quantification

Several staging systems, definitions of indolent disease and treatment guidelines for multiple myeloma and related conditions, are based on decision levels of BJP 24-hour excretion.
However, none of these studies specifies how to identify and measure “something called BJP”.
The clinical value of BJP quantification is limited by metabolic and analytical problems.
The excretion of BJP is influenced by its degree of polymerization, by renal function, and by the deposition rate of the protein in different tissues, so the amount of BJP in urine is not directly related to the tumor cell mass.
Again, an accurate measurement of BJP cannot be easily achieved with present laboratory techniques.
The guidelines of the College of American Pathologists suggest the following procedure:

Measurement of total protein in a 24-hour specimen;
Electrophoresis and IF of concentrated urine to detect BJP;
Densitometric scan of the BJP peak; and
Determination of the ratio of the BJP peak percentageto the total protein.

This procedure has some drawbacks:

– Inaccuracy of the methods in use to measure total protein in urine: these methods are often insensitive to microproteins in general and to BJP in particular.However, if the urine electrophoresis shows that BJP constitutes almost all urinary protein excretion, the determination of total urinary protein performed in the same laboratory by the same method at two points in time may provide useful indications regarding the efficacy of therapy;

– Different proteins can have different affinities for the dyes used to stain electrophoretic strips, and thus a lack of linearity of the densitometric response can be observed;

– Quite often multiple bands of BJP are present in the urine or the BJP co-migrates with other proteins, so that it is difficult to delimit the BJP peak correctly by densitometry.

It is suggested that follow-up of patients be performed in the same laboratory in order to minimize analytical variability.

Immunochemical methods using antisera against FLCs have the drawbacks listed in the “Alternative approach”
Moreover:

– Antisera raised against a polyclonal mixture of LCs do not necessarily react in the same way with the monoclonal LCs of the sample;

– The molecular mass of BJP is quite variable; in urine, they appear as monomers (22 kDa), dimers (44 kDa), low molecular mass fragments, or can show a high degree of polymerization. The state of aggregation/ fragmentation of FLCs in urine is highly variable and unpredictable, depending on many. In addition, the antisera used for the quantification of FLCs are directed against epitopesthat are hidden in whole immunoglobulin molecules. In some severe conditions, such as AL, LC fragments of 5-18 kDa, comprising the amino-terminal region, are present in serum and urine and are the main constituents of amyloid fibrils. These pathogenic LC fragments can lack some or all relevant epitopes and be poorly recognized, or missed, by the antisera. All these factors can influence the immune reaction and may invalidate the calibration making the quantification of urinary monoclonal LC unreliable;

– The precision of the quantitative methods at the extremes of the dynamic range is poorly defined;

– There is no reference material for monoclonal LCs,and accuracy therefore remains an open problem;

– There is no standardization of the several methods available for the quantification of urine FLCs.

Results could differ significantly between methods; this represents a serious problem in consideration of the present extreme mobility of patients.
Despite all these drawbacks, the immunochemical estimation of BJP may be of clinical value to monitor the clone during treatment, but it is necessary to utilize the same antisera and calibrators throughout the followup and to keep in mind all the caveats listed above.
Recently, it has been reported that in LC myeloma the quantification of FLCs in serum by nephelometry
correlates with changes in urinary FLC excretion.
The authors suggest that serum measurements may be an alternative to the cumbersome 24-hour urine collections in monitoring patients with LC myeloma. However, more data are needed before considering this alternative.

INSTRUCTIONS TO BE FOLLOWED AFTER EXTRACTION

INSTRUCTIONS TO BE FOLLOWED AFTER EXTRACTION :

EXTRACTION

Definition

” Extraction is defined as complete, painless removal of tooth or tooth root with minimal trauma to surrounding investing structures, so that the wound heals uneventfully and there will be no post operative prosthetic problems”.

POSTOPERATIVE INSTRUCTIONS

Your dentist will place a cotton or gaze roll in the area of tooth extraction, which need to be hold or bite firmly so that it creates a pressure over the surgical or extracted tooth site for 30min. There is no need of replacing the cotton again unless you note an active bleeding from the site. If you notice any active bleeding after 30min consult your dentist immediately.
After you remove the cotton from your mouth have some cold things like ice-cream such that it come in contact with the extracted site
You are advised not to spit for the next 24 hours whether it might be your saliva or blood everything need to be swallowed, as spitting may create a negative pressure over the extracted tooth site and may initiate bleeding
you are not allowed to gargle for next 24 hours. Gargling may cause disintegration of the blood clot and may initiate bleeding from the extracted socket.
You are advised not to touch the area of extracted site either with your tongue or finger
You are advised not to have any hot food or beverages
You are advised to have only cold and soft food
You are advised for Application of ice pack
Avoid spicy and hard food items for next 24 hours
Avoid eating from the side where your tooth was extracted
After extraction chances of swelling is quite common, in such case don’t panic swelling comes down slowly as healing progresses.
Avoid hot fermentation on the side of extraction
Avoid hot food or beverages for next 24 hours.
You are advised not to skip antibiotic and analgesic medication prescribed by your dentist
You are advised to visit your dentist after one week for suture removal ( If sutures are placed)
You are advised to avoid smoking, consumption of alcohol and use of tobacco for next 48 hours
You are advised to restrict your self to calm activities ( Avoid vigorous exercise for next 48 hours)
If bleeding persists even after 24 hours immediately contact your dentist

MANAGEMENT OF THE DENTAL OFFICE

Successful practice is a result of proper management of resources, professional skills, and relationships with other health care providers and public in general. In India, commoners are largely dependent mainly on government health care delivery systems in which dental services are integrated with medical services, while the affluent get private services for a fee. In recent years, policies of the government have allowed the participation of individual and multinational groups in private health care systems. Dental requirements of the public in India are vast, varying and largely unmet

FRONT OFFICE PERSONNEL:
- The dentist may appoint a full time receptionist, a dental chair side assistant or a person who can do both the work and also part time personnel who will clean the floor, equipments etc.,
- The front office staff plays a vital role in the success of the practice. The receptionist should be able to handle all kinds of patients
- Receptionist should be the liaison between the dentist and patients. While giving appointments she should know the approximate time required for each treatment. She should be able to rearrange the appointments if such a situation emerges that the patient flow is regularly maintained without wasting any time
INTERIORS:
- The furniture in the reception area must be durable, esthetic and comfortable. It should neither be too cheap nor be excessively lavish
- It is better to have a sound proof operatory, atleast with the pediatric population in mind. A second waiting area between the reception and operatory may be incorporated
- Electrical connection must be concealed and designed keeping in mind the lighting, fan, exhaust, compressor, x- ray unit, computer, dental chair and music system
- The drainage connection must be designed to aid conduction of plumbing work with proper slopes for drainage etc., to avoid water stagnation in the pipelines and further inconvenience
- The floor and walls should be designed considering the esthetics. Design should be such that there is minimum possibility of dust accumulation. Rubberized vinyl flooring is advised as it is easy to keep clean
- A separate x- ray room with wall enclosed in a lead barrier will help to minimize x-ray hazards
- Autoclaving and sterilization may be carried out in a separate chamber, close to the work area
APPOINTMENTS:
- If a dental clinic is located close to government, commercial offices, corporate and business houses, the appointments are generally to be given in between 9.30 AM to 6 PM because most employees would like to avail treatment by taking permissible short break from their offices
- If the clinic is in a residential area, the appointments are generally fixed between 8.30AM to 12. 30PM and 4.30PM to 8. 30PM, because in the morning office goers can visit the dentist before going to the office, while the house wife can avail treatment after 10 AM, retired and old people can visit the dentist by 11AM children will be brought from school by 4.30 PM and the office goers can also come for treatment after 6PM from office
- Preferably, A diary has to be kept to note appointments so that there is no confusion over the appointments
- Patients should be scheduled to arrive atleast 15minutes before the scheduled appointment
- If possible the front office assistant should be trained to call each patient atleast half an hour before the appointment and confirm the appointment. This also could act as a reminder for the patient regarding his/ her appointment
STOCK AND MATERIALS:
- For the smooth functioning of the clinic, the assistant or the receptionist should have good knowledge about the materials used in the clinic
- The staff working in the clinic should know the amount of material required for a particular period, amount of material in the stock, quantity to order, from where to purchase, the mode of payment etc.,
- Care should be taken to have sufficient material in the stock, so that the routine work doesn’t get disturbed. Material should never be bought in excess than required for a particular period as most of them have a short shelf life
- The dental office should know how to make economical use of the materials
RECORDS AND ACCOUNTING:
- Maintanance of clinical records is a must and should be kept confidential. They not only serve as a basis for future treatment, but also as evidence in case of legal claims or when summoned by law
- Accounting includes:
  - Income generated
  - Expenses met
  - Tax paid
  - Interest on loans
  - Membership fee for associations
  - Professional indemnity etc.,
- The dentist himself or his/ her assistant can do accounting, but by preference should be done by a qualified auditor
MEASURE OF SUCCESS IN PRACTICE:
- ‘Success’ is a relative term
- A dentist who is well known and respected by his/ her fraternity for his/ her professionalism, loved by his/ her patients for his/ her concern, kindness and devoted work, when his/ her absence is felt- are some of the indicators of success
WASTE MANAGEMENT AND INFECTION CONTROL:
- Wastes have to be segregated before disposal
- Wastes that are hazardous may be disposed through companies that collect biomedical wastes and process them
- A tie up may be made with the nearest hospital to dispose wastes that are to be incinerated
- It is important to follow suitable infection control measures to prevent cross infection
- The dental assistant may be taught the use of an autoclave so that he/ she sterilizes instruments on time
- Hand washing between patients not only protects the clinician from cross infection but also gives the patient a sense of comfort and increases the confidence of the patient on the dentist
- The parts of the chair that are generally contacted like the light handle etc., may be wrapped with a polythene sheet or aluminum foil, which may be replaced between patients
- Use of a head cap, face mask and gloves help prevent contracting infection from the patient
GROWTH AND EXPANSION:
- Related directly to the ability of the dentist to deliver thorough performance
- It is the measure of popularity achieved and monetary status achieved over a period of time
- Expansion is the extension of the operatory and inclusion of qualified associates into practice
MISCELLANEOUS:
- Dentist should have good communication skills.
- In the first visit itself, a detailed history must be obtained and the condition explained along with the approximate cost and mode of payment for the treatment
- It is a good practice to open the clinic atleast half an hour before the first appointment. The assistant must arrange instruments for each appointment at the right time
- Preferably, written instructions have to be given- it saves time
- It is better to have a link with credit card managers
- If possible an attachment to an insurance company or joining the medical panel of the company may be tried for
- The dentist should have an association with a good laboratory which promptly delivers the work on time
- Arrangement for proper waste disposal must be made
- All the professionals also need an occasional rest from work. A dental practitioner must take one day off from work every week, should have atleast 2 vacations every year to spend time with the family
- Whenever the dentist plans such holidays, alternative arrangements may be made to reduce inconvenience to the patients.

REFERENCES:

Essentials of Preventive and Community Dentistry- Soben Peter- 3^rd Edition
Textbook of Preventive and Community Dentistry- S S Hiremath- 1^st Edition
Essentials of Preventive and Community Dentistry- Soben Peter- 4^th Edition

Thyroid Gland

Introduction :

Thyroid gland lies deep to the sternothyroid muscle and sternohyoid muscle.
Thyroid gland is located anteriorly in the neck at the level of C5 – T1 vertebrae.
Thyroid gland consists of right and left lobes connected by “Isthmus”.
Right and left lobes are located anterolateral to the larynx and trachea.
Isthmus is located over the trachea usually anterior to the second and third tracheal ring

Thyroid Gland is surrounded by a thin fibrous capsule.
Thyroid Gland has a dense connective tissue which connects the capsule to the cricoid cartilage and to the superior tracheal ring.
External to the capsule there is a loose sheath formed by the pretracheal layer of deep cervical fascia.

VASCULAR SUPPLY :

Arteries :

Superior thyroid artery
Inferior thyroid artery

Thyroid Gland is highly vascular and is supplied by Superior thyroid Artery and Inferior thyroid artery which lies between the capsule and the pretracheal layer.
Superior thyroid artery descends to the superior poles of the thyroid gland, pierces the pretracheal layer and divides into anterior and posterior branches to supply anteriosuperior part of the gland.
Inferior thyroid artery is the largest branch of the thyrocervical trunk, it runs superiomedially posterior to the carotid sheath and reaches the posterior aspect of the thyroid gland.
They divide into several branches and pierces the pretracheal layer and supply the posterioinferior aspect of the gland and inferior poles of the thyroid gland.
The right and left superior thyroid artery and inferior thyroid artery anastamose with each other with i the gland.

VEINS :

Superior thyroid vein
Middle thyroid vein
Inferior thyroid vein+

Thyroid Gland is drained by 3 pairs of veins from the thyroid plexus of veins on the anterior surface of the gland anterior to the trachea.
Superior thyroid veins accompanies superior thyroid artery and drain the superior poles
Middle thyroid vein courses parallel to the inferior thyroid artery and drains the middle of the lobes.
Inferior thyroid vein drains the inferior poles.
Superior thyroid veins and middle thyroid vein drains into inferior juglar vein
Inferior thyroid vein drains into brachiocephalic veins

LYMPHATIC DRAINAGE :

The lymphatic vessels of the thyroid gland run in the interlobular connective tissue, they communicate with the capsular network of lymphatic vessels.
From the capsular network they pass first to the prelaryngeal lymphnodes, pretracheal lymph nodes and paratracheal lymphnodes whic in turn drains into superior deep cervical lymph nodes and inferior deep cervical lymph nodes.
Laterally, lymphatic vessels located along the superior thyroid vein pass directly to the inferior deep cervical lymph nodes.
some of the lymphatic vessels may drain into brachiocephaliclymph nodes or thoracic duct

NERVES :

These are derived from Superior cervical sympathetic ganglion, middle cervical sympathetic ganglion, inferior cervical sympathetic ganglion.. they reach the gland through superior thyroid periarterial plexuses and inferior thyroid periarterial plexuses that accompany the thyroid arteries.

Dental Practice Management

INTRODUCTION:

Patients, most commonly present themselves with painful tooth or bleeding gums to the dentist. The outcome is the relief provided for which the patient pays for the services, in full in private or partly in a government centre. The term ‘PRACTICE’ means arrangement or an agreement to provide certain services under a roof by an authorized person. ‘MANAGEMENT’ means the effective mode of provision of these services in a setting.

TYPES OF PRACTICE:

Solo practice– in this a dentist manages all types of cases according to his capacity
Group practice– here dentists trained in different specialties form a group and practice in the same office
Solo practice with visiting specialties– in this type of practice a single dentist manages the practice in his office but calls the specialists whenever required to carry out the specialty work

FACTORS ASSOCIATED WITH SUCCESSFUL PRACTICE:

Several factors are responsible for a successful dental practice, and are listed in the order of priority as:

Location for Dental Practice
Equipment and Materials
Financial Resources
Patients in Practice
Fee for Service
Personal Qualities required of the Dentist

1. LOCATION FOR DENTAL PRACTICE:

Is based on where the dentist would like to settle down
Established practice should not be shifted
Location may be classified as:
1. Business area:
  - Advantage- being centrally located, most people can easily locate the dentist when they are in need
  - Disadvantage- one will encounter difficulty in acquiring the ideal place, floor area, can be very expensive with high rental or building value
2. Professional area:
  - Advantage- Referral system is practices, specialists get to know each other by the practice of trade
  - Disadvantage- too many practitioners are concentrated at one place
3. Residential area:
  - Advantage- good relations develop with the people in the area
  - Disadvantage- confined to having patients within one locality
4. Floor plan must include-
  - Waiting hall
  - Consulting chambers
  - Private rooms
  - Operatory
  - X-Ray room
  - Recovery
  - Laboratory
  - Utility room
  - Rest room
5. Furnishing must be pleasant
6. Alterations in certain areas to accommodate patients with special needs are often necessary
7. Timings of the practice vary according to the location
8. The location should also be selected keeping safety in mind so that ladies also commute easily with no fear
9. The building for practice should preferably be in the ground floor, if not, elevator service must be made available , atleast with the geriatric group in mind
10. The building should preferably be a newly constructed one, so that it lasts for a longer time and has to be owned owing to advantages like:
  - No rent hike at regular intervals
  - No threat of evacuation
  - Building may be altered as per the wishes of the dentist without anyone’s consent
  - Convenient place may be chosen and suitable arrangements for parking may be made
11. It is also possible to practice at home if some alterations are made. It is apt for teachers who are employed by colleges, want to have limited practice in the evenings or a lady dentist who has to manage her house, family and profession
12. The design must be planned with the help of an architect, electrical connections are better concealed. Plumbing connections must be well planned. Design must be such that dust accumulation must be minimal and flooring must be easy to clean
13. The compressor and generator should preferably be placed in the basement to reduce noise level
14. All the required statutory licenses should be attained. It is better to have insurance coverage against fire, natural catastrophes, burglary and riots

2. EQUIPMENT AND MATERIALS:

Success also depends on right selection of equipments and instruments
The dentist should attend conferences, visit stalls during exhibitions to get familiarized with the latest equipments and gadgets
While selecting instruments, finance has to be suitably arranged. Prime importance should be given to the reputation, guarantee, warranty, time, cost of repair and availability of spare parts etc.,
Basic equipments which are essential include:
- Dental chair
- Dental unit
- Light cure unit
- Ultrasonic scaler with tip
- X-Ray unit
- X-Ray developer
- Autoclave
- Amalgamator
- Ultrasonic cleaner etc.,

Disposable items are always preferred. Sterilized and preautoclaved materials should be preferred when one buys consumable materials like blades, suture materials, gloves, syringes, needles etc.,

3. FINANCIAL RESOURCES:

Financing a new practice is generally difficult
Appropriate sources e.g., banks, financiers, state financial corporations have to be identified
Care should be taken to be familiar with the rules, terms and conditions before availing financial assistance
Applicant who is of a good standing, having all documentation and a guarantee should be able to avail the grants and loans from institutions
Patient record with fees must be maintained
The help of a chartered accountant must be sought at the initial stage of setting up of the clinic

Tax planning and filing of tax returns must be kept in mind

4. PATIENTS IN PRACTICE:

Patients differ from their race, culture, religion, occupation, socioeconomic status, behaviors, and personalities. The dentist should be discreet and polite
Preference is to be given to those who value treatment to those who are ‘window shoppers’
Emergencies must be addressed immediately and sympathetically
Satisfied patients are a source of advertisement to the dentist
The dentist must maintain a high standard of honesty, work ethics and principles while he/ she is discharging his/ her duties

5. FEE FOR SERVICE:

There are neither fixed rate scales nor legal guidelines for charging fee.
Fee should ideally commensurate with the work done.
Pricing may vary between dentists in the same area or location.
Earning ‘target’ amount per day is unethical.
Profit at the end of the day is a welcome sign of growth.

6. PERSONAL QUALITIES REQUIRED OF THE DENTIST

Humane attitude-
- Patient is a human being and has their own fears, frustration, ambitions and expectations
- Individuality of the patient, his/ her humanity should not be forgotten
- Dentists have to develop a friendly understanding, tender and loving approach while dealing with patients who are often scared, suffering with pain, depressed etc.,
- Developing a humane attitude towards patients is very important

Confidence-
- Most important quality to succeed in life
- Unless the dentist has utmost confidence to provide the necessary, appropriate treatment resulting in uneventful success
Salesmanship-
- There is no point in being sentimental about money collection and dentists have to make profits
- This is based on how the dentist sells dentistry to his patients. This will happen only when you have convinced the patients the need for treatment and the ability of the dentist to communicate with the patient
Punctuality-
- Receiving patients personally at the scheduled time and delivering the treatment at the exact time is important
- Missed appointments affect both patients and dentist
- Being punctual pays dividends in practice as it builds patients’ confidence on the dentist and serves a lot of time enabling time to b used in a more productive manner
Perseverance-
- Striving for improvement is known as the pursuit of excellence
- The maxim ‘Arise, Awake and persevere not until the goal is achieved” should be the motto in life
Personality-
- Pleasing, soft spoken, with smile, well groomed with appropriate dress certainly along with skill, knowledge and confidence greatly contribute to success in dentistry
Politeness-
- Being polite is the least a dentist could do to a patient if not serving them
- The dentist has to be careful in observing and handling an array of patients of different age groups and sexes
Patience-
- This is another unique quality dentists must have in abundance
- Patience must be in not only in terms of getting patients but also in diagnosis and delivering quality service and collecting fee for service
- It is the key word for a successful practice
Good health-
- Dentist need to be physically, mentally & dentally fit without which the financial health cannot rewarding
- Dentist’s dental condition is equally important as every patient looks forward to the dentist from whom they are seeking as a model

REFERENCES:

Essentials of Preventive and Community Dentistry- Soben Peter- 3^rd Edition
Textbook of Preventive and Community Dentistry- S S Hiremath- 1^st Edition
Essentials of Preventive and Community Dentistry- Soben Peter- 4^th Edition

ACTINOMYCOSIS

Definition :

It is a chronic infection manifesting both granulomatous and suppurative features; and usually involves soft tissues and occasionally bone.

Types :

There are three types:

Cervicofacial,
Thoracic,
Abdominal.

Cervicofacial actinomycosis :

About 2/3rd of cases are cervicofacial.
It involves mandible, overlying soft tissues, parotid gland, tongue and maxillary sinuses.
Secondary spread to other areas of head may occur.

Historical background:

J Israel in 1877, isolated an organism belonging to genus Actinomyces.
Historically, such organisms were considered to be fungi and are associated with a disease in humans analogous to lumpy jaw disease of cattle.

At least three types of Actinomyces have been related to the disease.

israelii: It is responsible for disease in humans.
bovis: It is responsible for disease in cattle, but rarely in humans.
baudetti: It is responsible for diseases in cats and dogs.

Several species of Actinomyces are found as normal saprophytes in human oral cavity; including: A. israelii, A.naeslundii, A. propionicus, and A. eriksonii.
Except for A. Israelii, the role of these organisms in the disease is not established.
These are endogenous in origin, and are found in
Tonsillar crypts,
Salivary and dental calculus,
Mucosa of oropharyngeal and gastrointestinal regions.
Pathogenecity is attributed to changes in local or general environment

Characteristic features:

It is now recognized that Actinomyces are not fungi; but are Gram positive, microaerophilic, nonsporeforming, and non-acid-fast bacteria.
Like Nocardia and Mycobacteria, Actinomycetes, share characteristics of both bacteria and fungi. However, they are not sensitive to antifungal drugs

Pathogenesis:

Organisms gain entry into soft tissues directly or by extension from bone through Periapical, Periodontal lesions, Fractures, or Extraction sites.
When established, infection spreads without regard to fascial planes and typically appears on cutaneous rather than mucosal surfaces.

Clinical features:

Patients present with the following:
Soft or firm tissue masses on the skin; which have purplish, dark red, oily areas with occasional small zones of fluctuation.
Spontaneous drainage of serous fluid containing granular material. These granules are yellowish substances called sulfur granules, and represent colonies of bacteria.
Regional lymph nodes are occasionally enlarged.
Trismus: Not common; unless secondary infection.
Pyrexia: Usually the patient is not febrile; and does not feel ill.
Microscopically, it shows closely packed branching filaments 1 μ in diameter.

Radiography:

The common findings are

Radiolucent areas of varying sizes, and delay in healing of extraction sites
Periostitis
Diffuse mandibular radiolucencies and marked bone sclerosis.
Sequestra formation is occasionally present.

Laboratory studies:

ESR and WBC Count may be slightly elevated.
Whenever, a firm mass/infections, which does not respond to conventional antibiotic therapy, then actinomycosis, mycosis, mycobacterial infection, and neoplasms should be considered in diagnosis.

Differential diagnosis :

The following conditions should be considered:

Parotitis,
parotid tumors,
cervical tuberculosis, and
pyogenic OML.

Diagnosis is based on Culture and sensitivity testing, and Biopsy.

Management:

In the past, many therapeutic agents and techniques were used including:

Iodides,
Radiation,
Incision and drainage, and
Excision of soft tissues and bone.
Currently, iodides and radiotherapy are considered to be ineffective.

Incision and drainage:

All abscesses, regardless of how small they are, should be surgically disrupted with a hemostat and all loculations penetrated.
Hospitalization is required; because, antibiotics are administered parenterally: in high doses, for protracted periods of time, shows temporary resolution and recurrence.
Penicillin is the antibiotic of choice. The dose depends on severity of the disease. 10 to 20 million units
daily for 3 to 4 months; 3 million units IV every 4 hourly for 2 weeks or longer.
Subsequently; 0. 5 gm probenecid orally four times daily. This daily 2 gm probenecid will increase blood
concentration of penicillin 2 to 3 folds by inhibiting its renal excretion.

In patients allergic to penicillin:

Tetracycline (especially Minocycline 250 mg 4 times daily for 8 to 16 weeks, may be prescribed(Martin, 1985).
Erythromycin 500 mg 4 times daily for 6 months. The dosages and durations for therapy used are effective for most infections and result in temporary resolution, only to be followed by recurrence. Therefore, high doses for extended periods are recommended.
Sequestrectomy and saucerization may be necessary.
Follow-up: Radiographs are taken periodically to monitor changes in bone.

OSTEOMYELITIS

Introduction :

Osseous in Latin means bony and Osteon in Greek means bone. Myelos is marrow. Itis in Greek means inflammation.

Osteomyelitis means inflammation of medullary portion of the bone or bone marrow or cancellous bone.

Osteomyelitis was common earlier but at present the incidence of jaws was less because of worldwide availability of

Antibiotics.
Better awareness in medical and dental conditions.
Dental health care is increased day by day and even spread to layman.

Few cases even occur

Due to resistant organisms to antibiotics.
Medially handicapped individuals.

DEFINITION :

“An inflammatory condition of soft bone, that begins as an infection of medullary cavity and haversian systems of cortex and extends to involve the periosteum of the affected area”.

PREDISPOSING FACTORS :

Conditions that alters host defences and due to chronic debilitating systemic diseases:

Diabetes mellitus
Agranulocytosis
Leukaemia
Severe anaemia
Malnutrition
Drug abuse
Chronic alcoholism
Sickle cell disease
Typhoid (febrile illness)

Conditions that alter vascularity of bone :

Irradiation osteoporosis
Paget’s diseas
Fibrous dysplasia
Bone malignancy
Metallic bone necrosis (Hg, Bi, Ar)

Virulence of organisms:

Certain organisms precipitate thrombi formation by virtue of their destructive lysosomal enzymes.

ETIOLOGY:

Odontogenic infection from pulpal:

Periodontal tissues
Pericoronitis
Infected socket
Tumor
Cyst

Trauma:

Second leading cause
Especially from compound fracture

Infection of orofacial regions:

Periostitis following gingival ulceration
Lymph nodes infected from faruncles
Laceration
Peritonsillar abscess

Infection derived by haematogenous route:

Furuncle on face
Wound on skin
Upper respiratory tract infection
Middle ear infection
Mastoiditis
Systemic TB

CLASSIFICATION:

According to Topazian classification was done based on absence or presence of suppuration:

Suppurative
- Acute suppurative osteomyelitis
- Chronic suppurative osteomyelitis

i) Primary

ii) Secondary

Infantile osteolmyelitis
Non-suppurative osteomyelitis
Chronic sclerosing osteomyelitis

i) Focal

ii) Diffuse

Garre’s sclerosing osteomyelitis
Actinomycotic ostemyelitis
Radiation osteomyelitis
Specific infective osteomyelitis

i) TB

ii) Syphilis

Based on clinical course:

According to JOMS 1993: 51; 1994 by Hudson et al

Acute forms of osteomyelitis (suppurative and non-suppurative)

Contigous focus

i) Trauma

ii) Surgery

iii) Odontogenic infection

Progressive

i) Burns

ii) Sinusitis

iii) Vascular insufficiency

Hematogenous (metastatic)

i) Developing skeleton (children)

ii) Developing dentition (children)

Chronic forms of osteomyelitis

Recurrent multifocal

i) Developing skeleton (child)

ii) Escalated osteogenic activity (< age 25yrs)

Garre’s osteomyelitis

i) Unique proliferative subperiosteal reaction

ii) Developing skeleton

Suppurative or non-suppurative

i) Inadequately treated forms

ii) Systemically compromised forms

iii) Refractory forms

Sclerosing
- Diffuse

i) Fastidious microorganisms

ii) Compromised host and pathogen interface

Focal

i) Predominantly odontogenic

ii) Chronic localized injury

Based on pathogenesis of altered, vascular perfusion (Vibhagool et al, 1993)

3 types:

i) Haematogenous osteomyelitis

ii) Osteomyelitis secondary to a contiguous focus infection

iii) Osteomyelitis with or without peripheral vascular disease.

Classification and staging system for osteomyelitis (Cierny et al, & Vibhagool)

Anatomic type:

i) Stage I: medullary osteomyelitis – involved medullary without cortical, Haematogenous

ii) Stage II: superficial osteomyelitis – less than 2 cm bony defect without cancellous bone.

iii) Stage III: localized osteomyelitis – < 2 cm bony defect on radiograph, does not appear to involve both cortices.

iv) Stage IV: diffuse osteomyelitis – > 2 cm pathologic feature, infection, non-union.

Physiologic class:

i) Host – normal host

ii) Host – local compromise & systemic compromise

iii) Host – treatment is worse than disease

Systemic or local factors that affect immune surveillance, metabolism and local vascularity

i) Systemic – malnutrition, renal and hepatic failure, diabetes mellitus, chronic hypoxia, immune deficiency, malignancy, old ages, tobacco, alcohol abuse.

ii) Local – chronic lymphedema, venous stasis, major vessel disease, arthritis, extensive scarring, radiation fibrosis, small vessel disease, local loss of sensation.

PATHOGENESIS

Periapical and periodontal infections localised by protective pyogenic membrane

⇓ Sufficient virulent M.O

Destroy this barrier

⇓

Infection into the bone

⇓

Pus (necrotic tissue, dead cells) accumulates in canals (Yolkman Haversian)

⇓ ⇓

Vascular collapse (thrombosis) compression of neurovascular bundle

⇓ ⇓

Ischemia mandibular anesthesia

⇓

The island of dead bone formed becomes place for precipitate of ionized calcium mobilized form surrounding osteolytic process (so sequestrum appears more opaque).

If pus continues to accumulate the periosteum is penetrated and mucosal and cutaneous abscess and fistula develop.

Mechanical trauma burnishes the bone causing ischemia and introduces organism initiated by acute inflammation – hyperemia increase capillary permeability.

As natural host defences and therapy begins to be effective the process becomes chronic, inflammation regresses, granulation tissue is formed and new blood vessels causes lyses of bone thus separating fragment of necrotic bone from viable involucrum.

The process leading to the formation of osteomyelitis is initiated by acute inflammation, hyperemia increase capillary permeability, and infiltration of granulocytes.

Tissue necrosis occurs as proteolytic enzymes are liberated and as destruction of bacteria and vascular thrombosis continues, there is pus formation.

Radiographically: –

The bone surrounding sequestrum appears less densely mineralized than sequestrum. Ischemia causes increase in CO₂ level, which attracts calcium due to change in patient. The Ca deposition leads to increase in mineralization of the sequestrum.

Osteomyelitis in mandible: –

Osteomyelitis in mandible is common in adults. In craniofacial skeleton only the mandible and the calvarium have myeloid compartments.

The important factor in establishment of osteomyelitis is the compromise in the blood supply and venous drainage of mandible.

Blood supply: – Primary supply is through inferior alveolar artery, except coronoid process supplied temporalis muscle vessels.

Secondary supply is periosteal supply through, which generally runs parallel to cortical surface of bone giving nutrient vessels those penetrate cortical bone and anastomoses with the branches of inferior alveolar artery.

Venous drainage: – There are two routes via inferior alveolar vein.

It runs upwards and joins pharyngeal plexus.

It runs downwards and joins external jugular veins.

Walden (1943) gave a description of vascular morphology of mandibular and associated structures to account for spread of osteomyelitis. He described mandibular vascular support as being provided through multiple arterial loops from major vessels, which renders a large portion of bone susceptible to necrosis with the occurrence of major vessel infectious thrombosis.

Walsel Vogel (1970) describe,These tend to be segregation of terminal channels, which act like “end organs” due to lack of terminal collateral anastomoses, ultimately leading to vascular plugging by bacteria microthrombi or both. When afferent vessels anastomose with medullary channels there is a possibility of decrease in venous flow with associated areas of greater turbulence. These may be a reduction in host immune defence mechanism associated with these vascular channels in calcified tissue.

Osteomyelitis in maxilla: –

This is rare in adults due to

Extensive blood supply and significant collateral blood flow in mid face.
Porous nature of membranous bone.
Thin cortical plates.
Abundant medullary space.

These preclude confinement of infections with in bone and permit dissipation of oedema and pus into soft tissue and paranasal air sinuses.

MICROBIOLOGY: –

In past, the etiology of osteomyelitis was associated with skin surface bacteria, S. aureus and to lesser extent S. epidermidis, which was found that these organisms are found in bone not in skin.

However, aureus as primary offending pathogen does not hold true with regard to osteomyelitis.

Most of cases are caused by aerobic Streptococci (i.e., hemolytic streptococci, Streptococci viridans, anaerobic Streptococci, and Bacteroides)

Sometimes Klebsiella, Pseudomonas and Proteus are also found. Other organisms – M. tuberculosis, T. pallidium, Actinomyces, Coccidiodes, Tuberculosis bacilli, Treponema & Klebsei

EXTRACTION

Definition

Indications

Severe caries
Pulpal necrosis
Severe periodontal disease
Orthodontic reasons
Malopposed teeth
Cracked teeth
Prosthetic reasons
Impacted teeth
Supernumerary teeth
Associated with pathologies
Involved in fractures
Esthetics & Economics

Contra-indications

Absolute

Local
1. Hemangiomas
Systemic
1. Lymphomas
2. Leukemia
3. Thyrotoxicosis
  RI280897/13

Relative

Local
- Acute infection
- ANUG
- Acute pericoronitis
Systemic
- Diabetes mellitus
- Hypertension
- Pregnancy
- Heart disease
- Epilepsy

Evaluation of teeth removal

Access to Tooth
Mobility of Tooth
Condition of Crown

Radiographs

Indications for radiograph

Attempted extraction
Grossly decayed
Root canal treated
Supernumerary teeth
Impacted Teeth
Root stumps
Fractured Teeth $fractured tooth$

Radiographic evaluation

Condition of the Tooth.
Condition of the Bone.
Relationship with associated Vital structures.

Types of Exodontia

Intra-alveolar extraction also called as Closed extraction. Where tooth is luxated and elevated out of socket with elevators and forceps.
Trans-alveolar extraction in this method an incision is placed and mucoperiosteal flap is reflected for proper accessibility, bone cutting is done either with a chisel and mallet or a bur. Sutures are placed to approximate wound margins.

Principles of Extraction

Intra-alveolar or Closed method

Forcep blade should be placed below the C.E. junction on sound root portion with apical thrust.
Mechanical principles:
1. Expansion of bony socket
2. Use of lever and fulcrum to elevate the tooth.
3. Use of wedge or wedges within root or socket.
Traction towards least resistance.

Principles for deciduous teeth extraction

Gentle and Judicious use of elevators
Beak of the forceps should be carefully placed, so that it should not injure the hidden permanent tooth bud.

Order of extraction

To prevent bleeding from socket of extracted teeth obscuring the field of operation distal most tooth is first extracted.
Maxillary teeth should be extracted before mandibular to prevent falling of debris or totth material in to socket.
Canine should not be left last as alveolus may get fractured due to its length.

Forces during extraction

Apical force: to wedge the forceps firmly in the periodontal ligament space.this does not actually move the tooth but expands the bony socket
Buccal force: Expands the buccal cortical plate.
Lingual force: Expands the lingual cortical plate.
Rotational force: Teeth with single conical roots can be extracted by this method.it causes internal expansion of the bony socket.
Tractional force: These are forces applied finally to remove the tooth completeley out of socket.

Rules for application of forceps

Correct forceps for particular tooth should be selected.
Grasp the forceps at the far end of handles.
Long axis of the beaks of the forceps should be parallel to the long axis of the tooth.
Beaks should be firmly grasped on sound root structure, not on enamel of crown.
Beaks should not impinge on adjacent teeth.

Forces applied for different teeth

MAXILLARY:

Incisors: labial-lingual-labial with mesial rotation.
Cuspids: labial-lingual-labial with mesial rotation.
First premolar: buccal-palatal-removal in buccal direction.
Second premolar: buccal-palatal-removal in buccal or palatal direction.
Molars: buccal-slight palatal and distal rotation.

MANDIBULAR:

Anteriors: labial-lingual-slight mesial to distal force and removal in labial direction.
Premolars: buccal with slight mesio-distal rotation.
Molars: buccal-lingual and removal in buccal direction.
Third molars: buccal pressure and removal in buccal or lingual direction.

Complications of Exodontia

A complication is any deviation from normal expected pattern of events

Fracture of:

Crown of tooth. $crown fracture$
Roots of tooth. $root fracture$
Alveolar bone. $alveolar bone fracture$
Maxillary tuberosity.
Adjacent or opposing tooth.

Dislocation of:

Temporomandibular joint

Displacement of root:

In to the soft tissues
In to maxillary antrum

Excessive hemorrhage:

During tooth removal
On completion of extraction

Postoperatively

Damage to:

soft tissues
Inferior alveolar nerve and its branches
Lingual nerve
Tongue and floor of mouth

Post-operative pain due to:

Damage to hard and soft tissues
Dry socket
Acute osteomyelitis

Post operative swelling due to:

Oedema
Hematoma formation
Infection

Trismus

Oro-antral communication

HOW TO WEAR GLOVES ?

GLOVES

Gloves must be worn when skin contact with body fluids or mucous membrane is anticipated or when touching items or surface that may be contaminated with these fluids. After contact with each patient, gloves must be removed; hands must be washed and then regloved before treating another patient.

Repeated use of a single pair of gloves to disinfectant or other chemicals often cause defects in gloves, there by diminishing their values as effective barrier. Latex or vinyl gloves should be used for patient examination and procedure. Heavy rubber gloves also called utilizing gloves should preferably be used for cleaning instruments and environmental surfaces. Dentist show allergic reaction to latex gloves can use nylon glove liners under latex rubber or plastic gloves. Polyethylene gloves also known as food handler’s gloves may be worn over treatment gloves to prevent contamination.

A surgical glove is fitting and generally the most expensive disposable glove used in maximum protection is indicated.
Employers should not wash or disinfect the surgical or examination gloves for reuse.
No gloves should be used if they are peeled, cracked or discolored or if they have puncture, tears or other evidence of distortion.
Inadequate drying of the hands prior to gloving has proven to be another cause of dermatitis.
The utility gloves can be washed, sterilized, disinfected and rinsed and that are puncture resistant.

PRACTICAL POINTS ESSENTIAL FOR GLOVE USE

Wash hands before doing gloves
Choose a glove that fits tightly
Replace gloves immediately if born
Ensure chair side assistants wear gloves
Wash hands immediately after glove removal.
Treat gloves as surgical waste and dispose of them accordingly.

ASEPSIS

INTRODUCTION

The concept of asepsis and its role in the prevention of infection was put forward nearly 2 centuries ago. The general principles for asepsis were laid down by Hungarian abstetrician, Ignaz semmelweiss in europe in early 1850’s and Oliver Holmes in USA. These principles were accepted after Joseph Lister’s studies on prevention of wound infection carried out between 1865-91. Lister, working on antisepsis, initially used phenol (dilute carbolic acid) for contaminated wounds, later applied it in all surgical wounds, also in operating room by nebulization of the solution. Further developments occurred with the introduction of steam sterilization surgical masks, sterile gloves, sterile gowns and drapes etc. In present days certain guidelines and regulations are recommended by accepted bodies, which have to be followed in dental practice and up graded in every general body meeting.

CLASSIFICATION OF METHODS OF STERILIZATION

A. PHYSICAL

Sun Light
Drying
Heat
1. Dry
2. Moist
Gas
Filtration
Irradiation
Ultra sonic cleaning
Oil

B. CHEMICAL

Phenol Derivatives : Phenol, Cresol, resorcinol, chloroxylenol
Oxidizing agents : Pot. Permanganate, Hydrogen Peroxide, Benzoyol Peroxide
Halogens : Iodine, chlorine
Biguanide : Chlorhexidine
Quarternary Ammonium (Cationic) : Cetrimide, Zephiran
Soaps : of Sodium & Potassious
Alcohols : Ethanol, Isopropanol.
Aldehydes : Formaldehyde, Glutaraldehyde
Acids : Boric acid, acetic acid
Metallic salts ; Silver Nitrate, Zince Sulfate, Zinc Oxide, calamine, Ammoniated mercury.
Dyes : Gentian violet, proflamine, Acriflamine
Furan derivatives : Nitro flurazone

PHYSICAL METHODS

Sunlight : Most old & still effective. It possesses appreciable bactericidal activity. The action is due to ultra violet rays. This is one of the natural methods of sterilization in case of water in tanks, rivers and lakes.
Drying : It air has deleterious effect on many bacteria. Spores are unaffected by drying. Hence it is very unreliable method.
Heat : Is the most common and one of the most effective methods of sterilization.

Factors influencing sterilization by heat are : –

Nature of heat
1. Dry
2. Moist
Temperature & time
No of organism present
Whether organism has sparing capacity
Type of material from which organism is to be eradicated

A. DRY HEAT

Killing is due to :

Protein denaturation
Toxic effects of elevated levels of electrolytes

a. Red Heat : It is used to sterilize metallic objects by holding them in flame and heated red hot.

Example : inoculating wires, needles, forceps etc.

b. Flaming : The article is passed over flame without allowing it to become red hot.

Example : Glass plates, Cotton wool plays and glass slides.

c. Hot Air Oven: It is used to sterilize items, which do not get damaged by high temp. such as laboratory glass wave, flasks, scissors, impression trays (metal), all stainless steel instruments with sharp cutting edges, (preferred) B.P. handles, Dapen dishes, mouth mirrors and poles. Hot air is poor conductor of heat and poor penetrating capacity. So grease, oils, powders plastics, rubber-containing substances should be sterilized by other methods. High temp. can damage fabrics or melt them.

Temp. & Time: The sterilization is complete if these two factors are achieved throughout the load.

160^oC to 320^oF – 120/60 min
170^oC to 340^oF – 60 min
150^oC to 300^oF – 150 min
140^oC to 280^oF – 180 min

Precautions

The heat should be uniformly distributed in side the oven.
All the instruments must be clean of dry prior to wrapping.
It should not be over loaded.
Oven must be allowed to cool for about 2 hours before opening other wire glass will crack.

Sterilization Control of Hot Air Oven

Detectors as spores of non-pathogenous strains of clostridium tetani are used to test dry heat efficiency.
Browne’s tube (green spot) is available for checking sterilization by dry heat. A green color is produced after 60 min. at 160^oC.
Thermocouples may be used.

GLASS BEADS STERILIZER:

This method employs a heat transfer device. The media used are glass beads, molten metal and salt. The temperature achieved is of 220^oC. The method employs submersion of small instruments such as endodontic files and burs, into the beads; and are sterilized in 10 seconds provided they are clean. A warm-up time of at least 20 minutes is recommended to ensure uniform temperatures in these sterilizers.

Some hand piece can be sterilized by dry heat. The hand pieces should be carefully cleaned and lubricated with special heat resistant oils.

B. MOIST HEAT:

Effective by denaturation and coagulation of proteins.

a. Temperature below 100^oC.

Pasteurization – milk by Hold Method and Flash Method.
Vaccine bath – for vaccines
Inspissation

b. Temperature at 100^oC

Tyndallization
Boiling
Steam Baths

c. Temperature above 100^oC

AUTOCLAVE

These are three major factors required for effective autoclave :

Pressure: It is expressed in pressure (Pounds) pre square inch and it is 15-PSI pressure.
Temperature: To achieve required pressure, the temp. must be reached and maintained at 121^oC with the increase in temperature and pressure super heated steam is formed and removed Air from chamber and this brings about sterilization.
Time: Wrapped loads require a minimum of 20 min. After reaching full temperature and time cycle, a wide variety of materials can be sterilized by this method.

Example: Diagnostic and prognostic Instruments, plastic filling Instrument, impression trays, laboratory equipments, surgical instruments etc. Higher temperature and greater pressure shorter the time required for sterilization.

Pressure	Temperature	Time (Min.)
15 psi	121^oC	15
20 psi	126^oC	10
20 psi	134^oC	3

Time required to sterilize for a particular item also varies with the amount of material for the thickness of the wrap.

IRRADIATION

Radiation used for sterilization is of two types

Ionizing radiation, e.g., X-rays, gamma rays, and high speed electrons and
Non-ionizing radiation, e.g. ultraviolet light, and infrared light. These forms of radiation can be used to kill or inactivate microorganisms.

Ionizing Radiation

It is effective for heat labile items. Bellamy (1959) reported that it has great penetrating properties. It is commonly used by the industry to sterilize disposable materials such as needles, syringes and swabs.

The lethal action of this radiation is believed to be due to its effect on the DNA of nucleus and on the other vital cell components. There is no appreciable rise in temperature. High energy gamma rays from cobalt-60 are used to sterilize such articles.

Non-ionizing radiation

Two types of non-ionizing radiations are used for sterilization:-

Ultraviolet

It is absorbed by proteins and nucleic acids and kills microorganisms by the chemical reactions it sets up in the bacterial cell. It has low penetrating capacity and its main application is purification of air in operating rooms; viz, to reduce the bacteria in air, water and on the contaminated surfaces. All forms of bacteria and viruses are vulnerable to ultraviolet rays below 3000 atmospheric pressure. Excessive exposure of skin can produce serious burns. Care must be taken to protect the eyes while using U-V radiation for sterilization.

Infrared

It is another form of dry heat sterilization. It is most commonly used to purify air, such as in the operating room. Infrared is effective, however, it has no penetrating ability.

ULTRASONIC CLEANING

Several studies have shown that, when performed correctly, ultrasonic cleaning will remove dried serum, whole blood, plaque, zinc phosphate cement, and polycarboxylate cement from instruments, metal surfaces and dentures. It has been found to be more effective than manual cleaning.

Ultrasonic cleaning minimizes the handling of contaminated instruments by the nurse and reduces the chance of injuries from sharp, contaminated instruments.

Instruments are loaded into a metal basket, which is then placed into the ultrasonic bath. The unit is activated for the time recommended by the manufacturer (usually about 6 minutes). Instruments, which are contained in cassettes, are cleaned for 12 minutes.

After the cleaning cycle is complete, the basket is taken to the sink and the instruments are carefully and thoroughly rinsed under tap water. The instruments are checked for residual debris, which may be safely removed manually.

Instruments are taken to the packaging area, where they are unloaded from the baskets onto a thick disposable paper towel. The instruments are thoroughly ‘pat’ dried using strong paper towels. Drying is important.

Small rotary and Endodontic instruments should be held in beakers of ultrasonic cleaning solution which are suspended in the cleaning bath

ULTRASONIC CLEANERS AND SOLUTIONS

The Clinical Research Associates (CRA) recommended the following ultrasonic cleaners:

BIOSONIC – Whaledent

T33C – Health Sonics Group

CLOSTER 3 – Provides ultrasonic clean, rinse and dry, but is noisy

Details of these cleaners are given in the report.

PROCEDURE

Ensure bath is 3/4 full as per manufacturer’s instructions.
Ensure lid is well fitting to avoid creating aerosols.
Instruments should always be placed in a basket within the bath to ensure that they are kept a proper distance from the bottom of the bath. Burs should be placed in the beakers provided.
Never overload the basket. Overloading the basket with instruments causes ‘wave shadows’ – inactive zones within the bath.
Choose cycles as per manufacturer’s instructions. Currently the counter top ultrasonic baths in use operate at <40 C. At this temperature a cycle of 15 minutes is recommended. Alkazyme is currently considered an appropriate solution to use in this manner. (If the throughput is very large and instruments are heavily contaminated it is currently recommended to change the solution twice daily after the a.m. and p.m. sessions respectively).
On removal of instruments rinse thoroughly (in basket) under running water, inspect for any residual cement etc., dry and pack.

Notes

Ultrasonic units should be tested on a regular basis. Place a piece of tinfoil in the solution and run the unit. If the foil shows uniform pitting after 5 minutes this indicates that the submerged items received adequate ultrasonic cleaning during the cycle. No holes or an uneven pattern may indicate that the machine is not functioning properly.
Every new solution must be ‘degassed’ by running the ultrasonic bath free of instruments for 15 minutes.
Ultrasonic cleaning is not suitable for hand pieces.
Amalgam carriers should not be placed in the ultrasonic bath

CHEMICAL METHODS

They are used to disinfect the skin of a patient prior to surgery, and to disinfect the hands of the operator. No available chemical solution will sterilize instruments immersed in it. Secondly, there is a risk of producing tissue damage if residual solution is carried over into the wound while it is being used. The chemicals used are

ALDEHYDE COMPOUNDS

Aqueous solution of formaldehyde (formalin) and
Glutaraldehyde (cidex) are effective disinfectants.

i. Formaldehyde: This is a broad-spectrum antimicrobial agent, which is used for disinfection. It is a hazardous substance, inflammable and irritant to the eye, skin and respiratory tract. This is used to upto 50⁰c and has limited sporicidal activity. It is used for large heat-sensitive equipment such as ventilators and suction pumps excluding rubber and some plastics.

ii. Glutaraldehyde: It is toxic, irritant and allergenic. It is a high level disinfectant. It is applicable where heat cannot be used. It is active against most vegetative bacteria (including M. Tuberculosis) and some viruses (including HIV and HBV), fungi and bacterial spores. It is frequently used for heat sensitive material. A solution of 2 percent glutaraldehyde (Cidex), requires immersion of 20 minutes for disinfection; and 6 to 10 hours of immersion for sterilization. Stonehill et al (1963) reported that glutaraldehyde kills vegetative bacteria, spores, fungi and virus by alkylation on a 10-hour contact. The Centre for Disease Control includes it in the list of effective agents against hepatitis viruses. It is also toxic and irritating, and hence, not used on certain surfaces such as furniture, walls and floors. It can be safely used on metal instruments (for less than 24 hours), rubber, plastics and porcelain. It is activated by addition of sodium bicarbonate, but in its activated form in remains potent only for 14 days

ALCOHOLS

Ethanol and isopropyl alcohols are frequently used as antiseptic. Alcohols possess some antibacterial activity, against some Gram-positive and negative bacteria, and especially against M tuberculosis. Alcohols act by denaturing proteins. They are not effective against spores and viruses.

The alcohol must have a 10 minute contact with the organisms. Solutions of 70 percent alcohol are more effective than higher concentrations, as the presence of water speeds up the process of protein denaturation as reported by Lawrence and Block (1968). The alcohols do not function as disinfectants when instruments, hand pieces, or other equipment are simply wiped with them, since they evaporate quickly. Alcohols can dissolve cements holding instruments together, and plastics may harden and swell in their presence.

They are frequently used for skin antisepsis prior to needle puncture. They are good organic solvents. Their benefit is derived primarily in their cleansing action. The alcohols must have a prolonged contact with the organisms to have an antibacterial effect. This contact is prevented due to its rapid evaporation. Alcohol is sometimes used as a rinse following a surgical scrub. Its effectiveness lies in the solvent action and not in its antibacterial properties. Ethanol (Ethyl alcohol) is employed in the concentration of 70 percent as a skin antiseptic. It has poor activity against bacterial spores, fungi, and viruses. It is used in the concentration of 60 to 70 percent v/v, for disinfection of skin. The alcohols do not have reliable sporicidal, virucidal, or fungicidal action; hence, they are not useful for sterilizing surgical instruments.

PHENOLIC COMPOUNDS

Phenol itself toxic to skin and bone marrow. The phenolic compounds were developed to reduce their side effects but are still toxic to living tissues. These compounds, in high concentration, are protoplasmic poison, and act by precipitating the proteins and destroy the cell wall.

Lawrence and Block (1968) reported that their spectrum of activity includes lipophilic viruses, fungi and bacteria but not spores. Hence these are approved by ADA for use as surface or immersion disinfectant.These compounds are used for disinfection of in animate objects such as walls, floors and furniture. They may cause damage to some plastics, and they do not corrode certain metals, such as brass, aluminium and carbon steel.

AQUEOUS QUARTERNARY AMMONIUM COMPOUNDS

Benzalkonium chloride (Zephiran) is the most commonly used antiseptic. Its spectrum of activity is primarily Gram-positive bacteria. It is well tolerated by living tissues. It is not widely used because of its narrow spectrum of activity.

IODOPHOR COMPOUNDS

Many studies have shown, that, iodophor compounds are the most effective antiseptics,. Iodine is complexed with organic surface-active agents, such as, polyvinylpyrrolidone (Betadine, Isodine). Their activity is dependent on the release of iodine from the complex. The surface agent is film forming; this prevents the solution form staining clothes or skin.

These compounds are effective against most bacteria, spores, viruses, and fungi. These are the most commonly used surface disinfectants along with hypochlorite. Concentrated solutions have less free ioidine. Iodine is released as the solution is diluted. An appropriate dilution is 1 : 2 : 3 parts of iodophor and distilled water, respectively.

Advantages are

Low toxicity.
Prolonged residual effect
Inexpensive and
Odorless.

Geraci (1963) reported that these compounds build up on the skin after successive scrubs, and that this provides long la

STORAGE OF STERILE GOODS

Literature reported that the storage of instruments is also a problem. The pattern of storage varies from place to place. They are either stored in drawers, or in containers, in packs or sterilized trays. The maintenance of sterility during transportation and storage is of utmost importance.

Packs should be stored with the following considerations

Instruments are kept wrapped until ready for use.
To reduce the risk of contamination, sterile packs must be handled as little as possible.
Sterilized packs should be allowed to cool before storage; otherwise condensation will occur inside the packs.
To prevent contamination from rodents, ants, and cockroaches, the store must be subjected to adequate pest control.
Materials should be stored at least 8” off the floor and 18” from the ceiling.
Sterile packs must be stored and issued in correct date order. The packs, preferably, are stored in drums which can be locked. Preset trays and cassettes, are useful as, the instruments can be organized as per the procedure