ORAL TISSUE DIAGNOSTIC SERVICES: A REVIEW OF THELITERATURETan B.H., Sial' CH. Oral Tissue Diagnostic Services: AReview of the Literature. Annal Dent Univ Malaya 1999; 6:27 - 30.

ABSTRACTDiagnosis by histopathology remams as one of the mostimportant investigative methods used to establish adefinitive diagnosis of a lesion or disease state. Theprovision of oral tissue diagnostic services is therefore anessential function of an Oral Pathology unit. A review of theEnglish language literature disclosed that much of thedocumented information on the patterns of oral diagnosticservices were from the United States, Canada and the UnitedKingdom. This paper provides an overview of such surveyscarried out in these countries.

Keywords: Oral pathology, diagnostic services

INTRODUCTIONAcquaintance with patterns of utilisation of oral pathologydiagnostic services is a necessity for extrapolating thegrowth and development of this field in future( 1-12). Theother main reasons include the need to instil greaterawareness amongst dental and medical professionals ofOral Pathology as a dental speciality and also toemphasise the importance of histopathologicalconfirmation of all excised tissues.The three main purposes of establishing tissue diagnosticservices are:1. To make available such a facility to the local general

dental or medical practitioners, hospital health careprofessionals and other health care providers.

2. As a means to obtain material for teaching purposes.3. To act as a source of research material for the study of

oral diseases in the local population.The procurement of a biopsy is part of the oral healthservices. This procedure is carried out by all dentalprofessionals. Previously, it was mostly performed by thedental specialists in particular oral surgeons. Howevernowadays, general dental practitioners also do biopsies.

Literature review of surveys of oral tissue diagnosticservicesUnitedStates of AmericaSurveys of tissue diagnostic services first started in the1950's. The United States of America was amongst theearliest countries involved in this auditing programme.In 1960, Shafer et al.(1) compared various aspects ofdental school biopsy services by means of a questionnaire.Questions were asked concerning the tissue diagnosticservice's availability, administration, support, fees, numberof specimens, utilization, number of malignancies andwhether students were required to perform a biopsy beforegraduation.(1)

In 1971 Pullon and Miller(2) did a similar studyand compared their findings with those conducted earlierby Shafer et al.(1) i.e. for the years 1953 and 1958. Theyfound that there has been a modest increase in the

Tan BH*, Siar CH**Dental Faculty, University of Malaya,50603 Kuala Lumpur

* Final Year Dental Student

**Professor, Department of Oral Pathology,Oral Medicine and Periodontology,Dental Faculty,University of Malaya,50603 Kuala Lumpur

**Name and address of the author towhom requests for reprints should be addressed.

percentage of schools offering a tissue diagnostic serviceto outside practitioners, with the dental schools assumingat least partial control of almost all these services. Theadministrative responsibility for the tissue diagnosticservice has been centred most often in the departments ofpathology or oral pathology in the past 11 years(2).Support for the service continued to vary widely amongthe schools. In 1953, about half the schools charged a feeto outside practitioners; in 1969, all but one charged a feeranging from US$5 to US $18.

Utilisation of dental school tissue diagnosticservices has increased greatly with more than 45,000specimens processed in ]969(2). The average number ofspecimens per laboratory increased 482% and 240% in1969 as compared with 1953 and 1958 respectively(1,2).The range of the number of biopsy specimens alsoincreased with three schools each processing more than3,475 specimens in 1969. The largest number ofspecimens processed by any school in 1953 was 690. Thedental school tissue diagnostic services showed aremarkable increase in utilisation by outside practitionersin 1969; the ratio of numbers of specimens from the schoolto the number of specimens from outside practitioners wasreversed compared with the 1953 figures. There was asignificant increase in the number of malignant specimensprocessed in 1969 but a moderate decrease in thepercentage of malignant specimens among the totalnumber of specimens(2). This is seen not only in theincreased numbers of biopsy accessions, which increasedby 37% in 1990 compared with the last survey in 1985, butis also reflected in the diversity of services now offered byoral pathologists as well as in the utilization of the servicesby outside practitioners(3). Viewing the increasing use ofdiagnostic service by outside practitioners, the increasedemphasis on teaching biopsy techniques in dental schoolsand emphasis on their value to the practitioner seem tohave been most successful. It is deeply believed that thesignificant factor resulting in the increased utilization ofdental school tissue diagnostic services by outsidepractitioners has been the increasing number of schools

28 Annals af Dentistry, University af Malaya Val 6 1999

requiring each student to perform at least one biopsybefore graduation. The number of schools with thisrequirement has been grown significantly(2).

CanadaFew surveys regarding the oral pathology biopsy serviceswere conducted in Canada. These pursuedrecommendations made at the teaching conference in OralPathology. In 1982, delegates attending the CanadianDental Association Oral Pathology Teaching Conference4

concluded that an active diagnostic oral pathology biopsyservice is an integral component of an oral pathologydepartment. Such a service is necessary to provideteaching material, to encourage students in the applicationof basic biological sciences in clinical practice and tomaintain staff expertise. Conference participants alsostated that students should be taught, or be made aware of,diagnostic laboratory and surgical pathology proceduresand should be encouraged to participate actively in thediagnostic process. Similar concepts are embodied in theAmerican Association for Dental Schools CurricularGuidelines for Pathology(5).

A survey by Priddy et al.(6) in 1984 wasundertaken to investigate the various administrative,pedagogical, service aspects of oral pathology andavailability of oral pathology services in Canadian dentalschools. Their report covers the accessioning period 1977to 1981 and reflects the administrative and teaching statusof the various services as of July 1982. It documents theviability of oral pathology services in Canadian dentalschools and the significant advances that have been madein the last five years(6).

The significance of an active oral pathologyservice in a dental school and its interfacing with theundergraduate curriculum comes at a time of greateremphasis on the biological principles underlyingdentistry(6). During the next 20-25 years dentists willassume a greater degree of responsibility for the overallhealth of their patients(8-9). If the practitioner is to have afirm understanding of the patho-biology of oral, paraoraland systemic disease, then the foundation for thisknowledge and its application must be set in the dentalcurriculum. In this regard, didactic and clinical oralpathology courses are vital to the dental education process.

The Canadian Academy of Oral Pathologyconducted a survey of its active members to obtaininformation on their demographics, professional activitiesand university affiliations, update data regarding Canadianoral pathology diagnostic services, assess the specialty'smanpower needs and Canada's present and future oralpathology needs(10). Data were also collected onCanadian oral pathology diagnostic biopsy services. Thissurvey(10) revealed actual conditions of oral pathologydiagnostic biopsy service pertinent to administration orstaffing, funding and source of accessions. Collated fromthe Priddy's( 6) 1984 report, the basic concept of biopsyservices has changed very little. Most laboratories arebased at dental schools. Their funding has not changesignificantly, with only a modest increase in the averagefee. However, there has been a continuous growth in theuse of these services in Canada, particularly by dentists in

general practice. The average annual number ofaccessions from eight services was 845 between 1977 and1981, while the average annual number from five schoolsreached 1,930 between 1987 and 1989(10). The rate ofgrowth was down, however. From 1977 to 1981,accessions increased 15 to 16 per cent annually, but byonly six to eight per cent per year, approximately, from1987 to 1989. Priddy's( 6) figures are not directlycomparable with those obtained by Daley et al. 's(1 0)survey, since more biopsy services were included in hissurvey.

In another related work in 1988, the relativeincidence of odontogenic tumours and oral and jaw cyst ina Canadian population was carried out( 11). The resultsgive important data on assessing geographic differences inthe incidence of lesions and to allow clinicians to makerealistic judgments in counseling patients before biopsyabout the probability of diagnosis and risks associated withnon-specific clinical or radiographic lesions(ll). Thisimplicated that the establishment of oral pathologydiagnostic services boost the dental professionalsknowledge( 12).

United KingdomIn 1997, as part of an ongoing medical audit programme inthe Oral Pathology Unit at the Birmingham DentalHospital and School, Williams et al.(13) conducted asurvey to assess the use by general dental practitioners ofan oral pathology diagnostic service over a 20-year period.They carried out a retrospective analysis of the number ofcases received for histological examination in 1975, 1984and 1994. As far as these authors are aware, there hasbeen no previous study of the use of such kind of serviceby general dental .practitioners(13). In their study(13),1101, 2395 and 3366 specimens were accessedrespectively for the three years studied. The number andproportion of specimens received, number and proportionthat were hard or soft tissue specimens and the informationon the request form were recorded. A comparison wasmade between the provisional clinical and histologicaldiagnoses. They found that the number of specimensaccessed increased approximately 3-fold, but in reality thenumber of specimens accessed from general dentalpractitioners increased 5-fold. The variety of histologicalcategories increased by over 50%, most being soft tissuespecimens. The number of correct provisional diagnosesincreased steadily but the percentage with inappropriateprovisional diagnoses remained the same. Information onrequest forms steadily improved. Their survey showedthat the number of specimens received from general dentalpractitioners increased steadily over the 20-year period,which reflects increasing demand from this particulargroup of dental professionals for diagnostic histologicalservices, therefore confirming the need to provide thisspecialist service. Further, the range of diagnostic entitieshas widened. These trends indicate that general dentalpractitioners are treating a wider range of clinicalproblems than previously and presumably reflects thebetter training that is now available. However, while hardtissue lesions appear to present relatively little problem inclinical diagnosis, some oral mucosal lesions still present

difficulties. In view of the continuing dental educationandan increased knowledge of the differential diagnosis ofmucosal lesions these diagnostic difficulties shouldcontinueto decline(13).

Besides the above mentioned studies conductedon tissue diagnostic services, there were also severalrelated investigations notably those concerning oralsurgery services. Because trends and demands in oralsurgery services would directly or indirectly influencetissue diagnostic services it is felt that it would bepertinent to discuss this here. In 1994 Thomas et a1.(14), inCardiff carried out a survey on the provision of oralsurgeryservices in England and Wales from 1984 to 1991.A previous National Audit demonstrated a substantialincrease in demand for oral surgical services in Englandand Wales in the period 1979-1984. Despite a 32%increase in patient throughout and a 52% increase in minororal surgery carried out within the General Dental Serviceduring that period, a 66% increase in the numbers ofpeoplewaiting for in-patient surgery also occurred. Thesefindings suggested that demand for these services wasexceedingly high. This study, however, only investigatedchanges up to the end of 1984 and a second audit is nowneeded; particularly as the rate of change repOlted in theprevious study was rapid in,_many areas and currentactivity is the basis upon which contracts for the purchaseof care are being drawn up and policy concerningspecialist oral surgery practice is being developed( 15).

Data from the Department of Health and theDental Practice Board demonstrate substantial increases inthe volume of oral surgery performed in England andWales both in the General Dental and Hospital Servicesduring the period 1984-1991 (Dental EstimatesBoard/Dental practice Board Annual Report)(16). In theGeneral Dental Service(GDS), although the number ofroutine extractions decreased by 10%, the number ofsurgical procedures increased by 20%, with a substantialincrease (33%) in the number of third molar extractions inthe period 1988-1991. There have been no decreases inthe annual rate of extractions of permanent and deciduousteeth in the GDS since 1987. In at least one RegionalHealth Authority, there was a five-fold increase in thenumber of oral surgery patients aged 0-9 years treated inthe hospital service (1982-1991). Overall, although thisstudy takes no account of extractions carried out in theCommunity Service, these findings suggest that thenumbers of deciduous extractions may have actually risenin some areas, particularly after 1987. In the HospitalService there was a 55% increasc in numbers of day-cases,from 30,090 (1984) to 46,499 (1990); a 10% increase innumbers of in-patients and a 13% decrease in numbers ofpeoplewaiting for in-patient surgery. These changes werein the same direction as those in plastic and ENT surgery;though plastic surgery achieved a greater utilization ofday-care services. Through their study Thomas et a1.(14),demonstrated how the practice of oral surgery iscontinuing to evolve in the United Kingdom.Rationalisation in the provision of oral surgery services islikelyto occur in the next decade; with increasing numbersof patients requiring minor oral surgery being treated intheGDS. Such changes will have important implicationsfor manpower planning and education. These include

Oral Tissue Diagnostic Services: A Review a/the Literature 29

increasing emphasis on oral surgery training in the dentalundergraduate course and in vocational training and thedevelopment of training programmes for specialistpractitioners both for the GDS and for the hospital service.

In short, the review indicated that the provision oforal surgery increased during 1984-1991, and suggests thatmore will be carried out in general practice in the future.

In a simpler way, the provision of oral pathologydiagnostic services has a significant effect on the overall 'performance of dental services. This is not helped by thelimited research on the utilisation of such kinds of service.Over the years, considerable changes have been made notonly to improve and advance our system of education, butalso in the provision of health needs including dentalhealth services. In order to determine whether suchchanges affect the biopsy services or the use of laboratoryservices, auditing programmes should be devised to \monitor these changes more effectively.

For all years, periapical scar tissue wasconsistently incorrect diagnosed clinically because o~ itsrare occurrence. Hence the dental practitioners havedifficulty diagnosing them clinically. The dental folliClewas one of the consistently incorrect diagnosed lesionsdespite of its typical site of occurrence. Chronichyperplastic candidiasis as one of the consistentlyincorrectly diagnosed lesions is relatively uncommoncondition and only a small number of cases weresubmitted.

CommentIn modern day dentistry, the dentists will have to assume agreater degree of responsibility for the overall oral healthof their patients. The practitioners should have an in-depthknowledge and understanding of the pathobiology of oral,paraoral and systemic diseases. To achieve this aim, it is amust to set a foundation for this knowledge and itsapplication in clinical time. These could be set in theundergraduate dental curriculum. In this regard, didactic'and clinical oral pathology courses are vital to the dentaleducation process. This change of responsibility will haveimportant implication for manpower planning besides theaspect of education. More oral pathologists would beneeded in educational activities. They would probablydevote bigger portion of their time to teaching.

It is obvious right from the start that oralpathology diagnostic service is important both to dentalstudents and practitioners. The service acts as a source ofresearch material for the study of oral diseases andsubmission of surgical material for undergraduate andgraduate teaching purposes. Furthermore, it providesdiagnostic aid to the practitioners to reach a definitivediagnoses. With its significance, continuing efforts mustbe made to ensure that the service and teaching role remainin step and are responsive to the profession as it movestowards the next century.

ACKNOWLEDGEMENTSThis paper is part of an elective student project presentedat the First Dental Student Scientific Conference held herein Kuala Lumpur on 19-20 November 1999. The authorsgratefully acknowleged the assistance of all the staff of theDepartment of Oral Pathology, Oral Medicine &

30 Annals of Dentistry, University of Malaya Vol 6 1999

Periodontology; and the support and subsidy approved bythe Dean, Faculty of Dentistry to fund this study.

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