Dental students' perception of their approaches to learning in a PBL programme

AIM

To compare dental students' perceptions of their learning approaches between different years of a problem-based learning (PBL) programme. The hypothesis was that in a comparison between senior and junior students, the senior students would perceive themselves as having a higher level of deep learning approach and a lower level of surface learning approach than junior students would. This hypothesis was based on the fact that senior students have longer experience of a student-centred educational context, which is supposed to underpin student learning.

PARTICIPANTS AND METHODS

Students of three cohorts (first year, third year and fifth year) of a PBL-based dental programme were asked to respond to a questionnaire (R-SPQ-2F) developed to analyse students' learning approaches, that is deep approach and surface approach, using four subscales including deep strategy, surface strategy, deep motive and surface motive. The results of the three cohorts were compared using a one-way analysis of variance (ANOVA). A P-value was set at <0.05 for statistical significance.

RESULTS

The fifth-year students demonstrated a lower surface approach than the first-year students (P = 0.020). There was a significant decrease in surface strategy from the first to the fifth year (P = 0.003). No differences were found concerning deep approach or its subscales (deep strategy and deep motive) between the mean scores of the three cohorts.

CONCLUSIONS

The results did not show the expected increased depth in learning approaches over the programme years.

A predictive model for alternative admission to dental education

AIM

To compare academic progress and performance of students admitted through two admission systems and to analyse the predictive power of different components in an alternative admission.

SAMPLE AND METHODS

The subjects were students admitted to the dental programme at Malmö University, Sweden. The grade admission group was admitted on grades from secondary school (n = 126) and the alternative admission group via an alternative admission procedure (n = 157). The alternative admission procedure consisted of the following components: problem-solving matrices, spatial capacity tested with folding and tin models, manual dexterity, capacity for empathy and interview. Comparisons were made for academic progress (dropouts from the programme and study rate) and academic performance (examinations failed and outcomes of a comprehensive clinical examination). Spearman correlation was calculated for each component of the alternative admission procedure and academic progress as well as academic performance. Multivariate analyses were also carried out.

RESULTS

Compared to the grade admission group, the alternative admission group presented lower rate of dropouts (3% vs. 20%, P < 0.001) and a larger proportion graduated within the expected time (88% vs. 60%, P < 0.01). There was no difference between the groups concerning academic performance. Capacity of empathy was correlated with study rate and outcomes of the clinical examination. The matrices predicted low proportion failed examinations and high students' self-assessments in the clinical examination. Predictive power of folding was limited and so was that of the interview. Manual dexterity was not correlated with academic progress or performance.

CONCLUSIONS

Results support further development of admission selection criteria, particularly emphatic capacity that predicts important student academic achievements.

Effective dose of cone beam CT (CBCT) of the facial skeleton: a systematic review

OBJECTIVE

To estimate effective dose of cone beam CT (CBCT) of the facial skeleton with focus on measurement methods and scanning protocols.

METHODS

A systematic review, which adhered to the preferred reporting items for systematic reviews (PRISMA) Statement, of the literature up to April 2014 was conducted. Data sources included MEDLINE®, The Cochrane Library and Web of Science. A model was developed to underpin data extraction from 38 included studies.

RESULTS

Technical specifications of the CBCT units were insufficiently described. Heterogeneity in measurement methods and scanning protocols between studies made comparisons of effective doses of different CBCT units and scanning protocols difficult. Few studies related doses to image quality. Reported effective dose varied across studies, ranging between 9.7 and 197.0 μSv for field of views (FOVs) with height ≤5 cm, between 3.9 and 674.0 μSv for FOVs of heights 5.1-10.0 cm and between 8.8 and 1073.0 μSv for FOVs >10 cm. There was an inconsistency regarding reported effective dose of studies of the same CBCT unit with the same FOV dimensions.

CONCLUSION

The review reveals a need for studies on radiation dosages related to image quality. Reporting quality of future studies has to be improved to facilitate comparison of effective doses obtained from examinations with different CBCT units and scanning protocols. A model with minimum data set on important parameters based on this observation is proposed.

ADVANCES IN KNOWLEDGE

Data important when estimating effective dose were insufficiently reported in most studies. A model with minimum data based on this observation is proposed. Few studies related effective dose to image quality.

Variation in costs of cone beam CT examinations among healthcare systems

OBJECTIVES

To analyse the costs of cone beam CT (CBCT) in different healthcare systems for patients with different clinical conditions.

METHODS

Costs were calculated for CBCT performed in Cluj (Romania), Leuven (Belgium), Malmö (Sweden) and Vilnius (Lithuania) on patients with (i) a maxillary canine with eruption disturbance, (ii) an area with tooth loss prior to implant treatment or (iii) a lower wisdom tooth planned for removal. The costs were calculated using an approach based on the identification, measurement and valuation of all resources used in the delivery of the service that combined direct costs (capital equipment, accommodation, labour) with indirect costs (patients' and accompanying persons' time, "out of pocket" costs for examination fee and visits).

RESULTS

The estimates for direct and indirect costs varied among the healthcare systems, being highest in Malmö and lowest in Leuven. Variation in direct costs was mainly owing to different capital costs for the CBCT equipment arising from differences in purchase prices (range €148 000-227 000). Variation in indirect costs were mainly owing to examination fees (range €0-102.02).

CONCLUSIONS

Cost analysis provides an important input for economic evaluations of diagnostic methods in different healthcare systems and for planning of service delivery. Additionally, it enables decision-makers to separate variations in costs between systems into those due to external influences and those due to policy decisions. A cost evaluation of a dental radiographic method cannot be generalized from one healthcare system to another, but must take into account these specific circumstances.

Dentists reflect on their problem-based education and professional satisfaction

AIM

To determine the way in which Malmö University dental graduates perceive their problem-based dental education and evaluate their professional satisfaction.

METHOD

The first five cohorts (graduating in years 1995-1999) of the problem-based curriculum were invited to participate. Of 166 graduates, 77% responded to a questionnaire comprising 20 questions on aspects of their dental education, professional situations and interest in postgraduate education. They were asked to rank their perception of their dental education and satisfaction with their professional situation on a visual analogue scale (VAS) with endpoints ranging from 'Not at all' (1) to 'Very well' (10). For other statements, the markings were made on a Likert scale from 1 (not important/not satisfied) to 5 (very important/very satisfied). There were also open-ended questions.

RESULTS

Most respondents perceived their education to prepare them well for a career in dentistry (median score VAS 8), and 90% rated above six on a VAS for their professional satisfaction as dentists. Importance and satisfaction were highly correlated with principles of the curriculum: holistic view, oral health, lifelong learning, integration between theory and clinic, and clinical competence. Forty-five per cent of the graduates noted the problem-based learning approach as the most valuable asset of their education, and 19% cited training in oral surgery as a deficit. Of the respondents, 77% expressed interest in specialist training and 55% in research education.

CONCLUSION

Problem-based education was perceived to prepare graduates well for their profession, and their professional satisfaction was high.

Evidence-based care and the curriculum

An evidence-based (EB) approach has been a significant driver in reforming healthcare over the past two decades. This change has extended across a broad range of health professions, including oral healthcare. A key element in achieving an EB approach to oral healthcare is educating our practitioners, both current and future. This involves providing opportunities integrated within simulated and actual clinical settings for practitioners to learn and apply the principles and processes of evidence-based oral healthcare (EBOHC). Therefore, the focus of this discussion will be on ways in which EBOHC and associated research activities can be implemented into curricula, with the aim of improving patient care. This paper will initially define the scope of EBOHC and research, what these involve, why they are important, and issues that we need to manage when implementing EBOHC. This will be followed by a discussion of factors that enable successful implementation of EBOHC and research into curricula. The paper concludes with suggestions on the future of EBOHC and research in curricula. Key recommendations related to curricula include strengthening of the culture of a scientific approach to education and oral healthcare provision; complete integration of EBOHC into the curriculum at all levels; and faculty development to implement EBOHC based on their needs and evidence of effective approaches. Key recommendations to support implementation and maintenance of EBOHC include recognition and funding for high-quality systematic reviews and development of associated methodologies relevant for global environments; building global capacity of EBOHC researchers; research into improving translation of effective interventions into education and healthcare practice, including patient-reported outcomes, safety and harms, understanding and incorporation of patient values into EB decision-making, economic evaluation research specific to oral healthcare and effective methods for changing practitioner (faculty) behaviours; and extend access to synthesized research in 'user friendly' formats and languages tailored to meet users' needs. Realizing these recommendations may help to improve access to effective healthcare as a basic human right.

The oral ecosystem: implications for education

We propose a model that is applicable to oral health education. The model describes the oral cavity in a complexity-based ecological context. This concept includes the premise that factors from different organisational levels (biological, individual, community, society) interact in a complex way with the potential to 'stress' the ecosystem and thereby provoke changes. This mode of action complies with the understanding of the oral cavity as a complex adaptive system. An ecological model is actively used in the undergraduate problem-based curriculum at the Faculty of Odontology, Malmö University, Sweden and has recently been applied as a conceptual basis for the new dental curriculum being established at the University of Tromsø in Northern Norway. The purpose is to encourage and promote an ecological, health-oriented view and to stimulate reflections on premises for oral health and diseases in an integrated context.

Formation of a hard tissue barrier after pulp cappings in humans. A systematic review

AIM

To evaluate the evidence on the formation of a hard tissue barrier after pulp capping in humans.

METHODOLOGY

A PubMed and CENTRAL literature search with specific indexing terms and a hand search were made. The authors assessed the level of evidence of each publication as high, moderate or low. Based on this, the evidence grade of the conclusions was rated as strong, moderately strong, limited or insufficient.

RESULTS

The initial search process resulted in a total of 171 publications. After reading the abstracts and hand searching the reference lists of the retrieved publications, 107 studies were retrieved in full-text and interpreted. After the interpretation, 21 studies remained and were included in the systematic review and given a level of evidence. No study had a high level of evidence, one study had moderate and 20 studies had a low level of evidence. There was heterogeneity between the studies; therefore, no meta-analysis was performed. The majority of studies on pulp capping using calcium hydroxide based materials reported formation of hard tissue bridging, studies on other pulp capping materials such as bonding agents presented inferior results. The evidence grade was insufficient.

CONCLUSIONS

Insufficient evidence grade does not necessarily imply that there is no effect of a pulp capping procedure or that it should not be used. Rather, the insufficient evidence underpins the need for high-quality studies.

Third molar treatment outcome: a comparison of patients' preferences in Sweden and Wales

AIM

To elucidate and compare patients' outcome preferences for removal and retention of mandibular third molars in Sweden and Wales.

SUBJECTS AND METHOD

The subjects comprised patients referred and scheduled for removal of one or both mandibular third molars in Sweden and Wales. The multi-attribute utility (MAU) methodology was applied to study patients' preferences for outcomes of removal and retention of the mandibular third molar.

RESULTS

Relative weighting of domains was similar in the two countries. "Home and social life" received the highest relative weighting in Sweden and "general health and wellbeing" in Wales. "Your appearance" received the lowest relative weighting in both countries. In both Sweden and Wales operative jaw fracture was considered to be the outcome with most impact, and dentigerous cyst and imbricated incisors the least impact. Outcome ranking was similar in both countries and operative outcomes were considered by patients to be more detrimental to health than retention outcomes.

CONCLUSIONS

This comparison showed that patients' preferences in Sweden and Wales were similar and that the outcomes of surgery were considered worse after third molar removal than retention. Patient-orientated treatment decisions were less subject to variation than clinician-orientated decisions.

Continuing professional development--global perspectives: synopsis of a workshop held during the International Association of Dental Research meeting in Gothenburg, Sweden, 2003. Part 2: regulatory and accreditation systems and evidence for improving the performance of the dental team

This paper is the second in a series of two that report on continuing professional development (CPD). Details of the informants and the methodologies used were reported in the first paper. This paper reports the data and information presented on the topics of regulatory and accreditation systems for CPD and evidence that CPD improves the performance of the oral health team. By June 2003, participation in CPD was mandatory in most of the states of the USA, all Canadian Provinces, the UK and Latvia and was likely to become mandatory in a number of other countries in the near future. A variety of accreditation systems were reported including collecting CPD points, which in some countries were weighted depending on the type of CPD activity, and re-certification examinations. Very few studies for the effectiveness of dental CPD were identified. However, in general it was concluded that there is little evidence for the effectiveness of CPD for the oral health team. The main recommendation from this study is that a systematic review of the effectiveness of CPD in improving the performance of the oral health team and patient based outcomes be undertaken. A range of other research questions was also identified including: how can CPD be best matched to clinicians' needs rather than demands?

Continuing professional development--global perspectives: synopsis of a workshop held during the International Association of Dental Research meeting in Gothenburg, Sweden, 2003. Part 1: access, funding and participation patterns

There appears to have been little previous research interest in continuing professional development (CPD) of dentists and the oral health team. This paper presents data and information on the following aspects of CPD in 17 countries in Asia, Australasia, Europe and North America: availability of different types of CPD, its providers, data on uptake of CPD courses and activities, and funding of CPD. The results indicate that lectures and hands-on skills courses were held in all 17 countries but the use of the Internet to deliver CPD was by no means universal. CPD was funded from a variety of sources including universities, governments and commercial companies. However, the only universal source of funding for CPD was dentists themselves. Data on participation were available from only three countries. Research issues based on these results will be listed in a second paper.

Dentists' decisions on prophylactic removal of mandibular third molars: a 10-year follow-up study

OBJECTIVES

In recent years, several critical outcome studies concerning the prophylactic removal of mandibular third molars have been published. These would appear to motivate a more restrictive approach today as compared with 10 years ago. The aim of the present study was to examine dentists' decisions on the prophylactic removal of impacted mandibular third molars over a 10-year period.

METHODS

Thirty-six cases were selected so as to represent an equal distribution of males and females, ages, angular position and degree of impaction of the molar. Twenty-six general dental practitioners (GDPs) and 10 oral surgeons judged the same cases on two occasions 10 years apart.

RESULTS

Calculated for each category of dentists, there was no significant difference in the mean number of molars designated for removal between the two occasions. Two GDPs and three oral surgeons presented a higher removal rate, whereas five GDPs presented a lower removal rate on the second occasion as compared to the first one. The dentists presented a considerable interindividual variation in removal rate, between 0 and 22 molars on the first occasion and between 0 and 25 molars on the second occasion.

CONCLUSION

In the decisions on prophylactic removal of mandibular third molars, there has been no change over the last 10 years towards a more noninterventionist attitude. Thus, the dentists seem not to have been influenced by the evidence that this intervention is not cost-effective.

Comparison of decisions regarding prophylactic removal of mandibular third molars in Sweden and Wales

OBJECTIVE

To test the hypothesis that Swedish dentists schedule more mandibular third molars for prophylactic removal compared with UK dentists and oral surgeons.

DESIGN

Clinical and radiographic information relating to a stratified sample of 36 disease-free mandibular third molars (equal distribution of males and females, patients' age, angular position and degree of impaction) was presented to 26 general dental practitioners (GDPs) and 10 oral surgeons in Sweden and 18 GDPs and 10 oral surgeons in Wales who were asked to decide whether or not the third molars should be removed.

RESULTS

There was no evidence of any difference in mean number of molars scheduled for removal by the GDPs, but the Swedish oral surgeons scheduled significantly more third molars for removal than oral surgeons in Wales.

CONCLUSION

The less interventionist approach among oral surgeons in the UK may reflect the development and application of authoritative guidelines in the UK and an extensive debate concerning appropriateness of prophylactic removal there.

The outcomes of mandibular third molar removal and non-removal: a study of patients' preferences using a multi-attribute method

The aim was to study patients' preferences about outcomes of mandibular third molar removal and non-removal using multi-attribute utility (MAU) methodology. The study comprised three stages. Stage 1: Elicitation of domains, i.e. main areas of patients' lives which could be affected by third molar removal and non-removal. Stage 2a: Interdomain weighting was obtained by relative weighting of the domains elicited in Stage 1. Stage 2b: Intradomain weighting obtained by patients' designation of values for different health states of each domain. Stage 3: Rating of outcomes. The patients were asked to imagine experiencing a variety of outcomes of mandibular third molar removal and non-removal, described in 19 short vignettes. The numbers of patients interviewed for the three stages were 30, 78, and 55, respectively. Five domains were identified. The mean relative weightings were approximately equal for the domains "Home and social life" and "General health and well-being", followed in order of importance by 'Job and studies" and "Health and comfort of mouth, teeth and gums". "Your appearance" received the lowest mean relative weighting. The vignette, which described the presence of a fluid-filled sac and suggested that this tooth must be removed, received the highest mean preference (least effect on patients' lives). The lowest mean preference (most effect on patients' lives) was generated by the vignette, which stated that the jaw was broken and that the teeth must be wired together for 6 weeks. We conclude that, from the patient's perspective, outcomes of non-removal were preferable to outcomes of mandibular third molar removal.

Dentists' judgment strategies on prophylactic removal of mandibular third molars

The number of molars selected for prophylactic removal varies widely among general dental practitioners and oral surgeons. To understand the basis for such variations, we investigated two hypotheses: (1) Individual judgment strategies will differ concerning the use of cues (items of information), and (2) few dentists will integrate the cues according to evidence in the literature. To analyze 30 general dental practitioners' (GDPs) and 10 oral surgeons' use of cues in the judgment preceding the treatment decision, we used the Brunwik's lens as a conceptual model. The cues were the patient's age, and the angular position and the degree of impaction of the molar. The clinical situation was simulated by written case descriptions. The proportion of variation explained by the cues and their combinations (total model) varied between 61% and 100% and between 4% and 76% as main effects. Two GDPs and one oral surgeon integrated the cues additively, i.e., any of the cues is independent of the other cues in the judgment. In general, the dentists integrated the cues interactively, i.e., the impact of one cue depends on the levels of some other cues. Even though most variations in judgments were accounted for by the cues, the dentists did not integrate the cues according to evidence in the literature and lacked insight into their decision-making thought processes.

Case challenge: the case of the missing root tip

A 43-year old female had her left maxillary first molar removed by her dentist. Upon examining the tooth following the extraction, he discovered the distobuccal root was fractured. Inspection of the extraction site revealed the missing root remained in its alveolus. When attempts were made to remove the root, it suddenly disappeared. To our knowledge, no further efforts were made to locate the root. In the ensuing weeks, the patient's dentist inserted a three-unit bridge to fill the space created by the removal of the first molar. Two months after the extraction, the patient was referred to the Department of Oral Radiology at the University of Lund, Sweden, with a request for help in locating the lost root.

Decision analysis in dentistry--the last 30 years

OBJECTIVES

To review publications in dentistry of decision analyses during the last 30 years.

METHODS

A systematic review of the English literature from 1969 to 1998 was performed using specified indexing terms. The number of retrieved articles in dentistry was compared with the number of articles in medicine. The quality of articles in dentistry presenting a decision tree with utilities and a sensitivity analysis was judged using a published peer review process. We report weaknesses of the analyses together with selected applications.

RESULTS

Sixty-seven articles were published on decision analysis in dentistry. Whilst the number of articles published in medicine has accelerated there has been a decline in the last four years in dental publications. Only 22 of the articles in dentistry presented a decision analysis with utilities and a sensitivity analysis.

CONCLUSIONS

Current weaknesses of the decision analyses reported were: opaque basic assumptions in the description of the analysis, lack of data on patient preferences and of reliable data on the chances of the long-term effects and side effects of intervention together with an absence of sensitivity analyses. The decision analysis approach complements that of "evidence-based health care" by enabling the best empirical evidence to be used in clinical practice. Formal methods such as decision analysis will promote the rational use of existing knowledge. For it to do this the quality of research data will have to improve in dentistry. Furthermore decision analysis is important in education to demonstrate explicitly how decisions might be arrived at and improved.

Case challenge. Chronic maxillary inflammation

A 30-year old male was referred by a dental practitioner to the Department of Oral Radiology at the University of Lund, Sweden, for a radiological evaluation of chronic symptoms of inflammation on the right side of the maxilla. According to the patient, at age 12 he had surgery to remove a non-erupted maxillary right second premolar. Postoperatively, a draining sinus tract appeared on the buccal aspect of the alveolar process. Thirteen years later, at age 25, surgery was again performed and the sinus tract reappeared. Intermittent discharge of exudate from the sinus tract occurred since the second surgery. Clinical and radiological examinations were conducted prior to a third surgery. The clinical examination revealed pus draining from the tract located on the buccal aspect of the alveolar process between the right maxillary first molar and first premolar. The radiological examination included periapical radiographs of the right maxillary first premolar and canine, a panoramic radiograph, and frontal tomograms of the maxillary right premolar area.

Mandibular third molars: oral surgeons' assessment of the indications for removal

The aim was to examine oral surgeons' assessment of the indications for removal of mandibular third molars. Questionnaires were distributed to seven oral and maxillofacial surgery clinics. The oral surgeons were asked to record whether or not there was associated disease. Three other factors were recorded: patient's age, and angular position and extent of eruption of the molars. The strength of the indication for removal was rated on a visual analogue scale (VAS) where 0= weakest and 100= strongest indication for removal. The results were based on data from 666 molars: 118 (18%) had no disease, 465 (70%) had one associated disease, 77 (11%) had two and 6 (1%) had three. The indication for removal as expressed by the mean VAS for molars with no disease was assessed to be weaker (P<0.05) than that for molars with one, two, or three diseases. The only factor that influenced the indication for removal in molars with no disease was the patient's age.

Effects of collimator size of a dental X-ray unit on image contrast

OBJECTIVES

To examine the effect of collimator size on image contrast in dental radiography.

METHODS

Two conventional collimators, one circular (53 mm in diameter) and one rectangular (35x45 mm2), were compared with a small rectangular collimator (26x39 mm2). Low-contrast and high-contrast resolution was assessed with the aid of contrast-detail and line-pair phantoms.

RESULTS

Shallower holes were observed with the small rectangular collimator. Two-thirds of 17 observers assessing high-contrast resolution considered the small collimator to result in a clearer image than the conventional collimators. The same effect was demonstrated with the line-pair phantom and by microdensitometry. With the small collimator the energy imparted is estimated to be reduced by 54 and 36% compared with the conventional circular and rectangular collimators respectively.

CONCLUSIONS

Decrease of the collimator size to fit the film size used for children will result in improved low-contrast and, under some conditions, improved high-contrast resolution. This improvement might have implications for caries diagnosis and monitoring.

The Malmö model: a problem-based learning curriculum in undergraduate dental education

A new undergraduate dental curriculum was introduced in Malmö in 1990 which is based on problem-based learning (PBL). The principles of PBL are strongly influenced by evidence from cognitive psychology and they form the educational strategy throughout the whole curriculum. Two further essential principles underpin the curriculum: a holistic attitude to patient care, and the promotion of oral health. Basic sciences and clinical dentistry are integrated within a structure based on oral conditions prevalent in the community. Students are encouraged to build their new knowledge, understanding and skills into the context of what they have already learned. This approach is facilitated by the presentation of conceptual models, one of which, The Oral Ecosystem is described in detail. The educational programme also gives students opportunities to learn in the clinical context from an early stage, and we endeavour to promote a scientific attitude from the very beginning of the programme. This paper describes the curriculum at three organisational levels (whole curriculum, single course, individual week).

Intra-observer reliability regarding removal of asymptomatic third molars

OBJECTIVE

To investigate reliability of practitioners' removal decisions and judgements of risk of pathology associated with asymptomatic third molars.

SUBJECTS

10 oral surgeons and 18 family dentists from South Wales with experience ranging from 5 to 28 years.

METHOD

Participants were presented with periapical radiographs of 36 asymptomatic, mandibular third molars and were informed of the age and sex of the patients and the degree of eruption of the third molars. Participants were asked to assess, using visual analogue scales, the likelihood of future pathology if the third molars were left in situ and to indicate if they should be removed or not. To assess intra-observer reliability, the 36 cases were duplicated and presented to the participants on a different occasion, a month later. The same questions were asked as on the first occasion.

RESULTS

Significant correlations (Pearsons correlation coefficients) were found between initial and repeat assessments of all measures but there was little agreement about the need for removal (Kappa values: 0.54 for oral surgeons and 0.41 for the family dentists). For every item studied, changes in position on the visual analogue scale of two-thirds or more of the total length occurred from the first to the second assessment.

CONCLUSION

Treatment decisions about whether or not to remove asymptomatic third molars were not made on a rational basis. Since similar conclusions were recorded in a previous Swedish study, it is inferred that until further high quality evidence of disease prediction is published, decisions to remove third molars prophylactically cannot be made reliably.

Mandibular third molars as mediated by three cues. Dentists' treatment decisions on asymptomatic molars compared with molars associated with pathologic conditions

The aim was to study how three cues (patient's age and angular position and degree of impaction of the molar) were distributed among removed mandibular third molars associated with pathologic conditions and to compare these results with dentists' treatment decisions in another group of molars consisting of asymptomatic mandibular third molars, as mediated by the same cues. The overall agreement was fairly high between the dentists' treatment decisions and the removal rate among the molars subjected to removal. Thus, molars partially covered by soft tissue in patients aged 19 to 40 years had a high removal rate, and molars totally covered by bone tissue had the lowest removal rate in accordance with the dentists' treatment decisions. There were some exceptions. For example, molars partially covered by soft tissue in horizontal and mesioangular positions were rated higher by the dentists than the removal rates indicated. Distoangular molars in patients aged 26 to 40 years had the highest removal rate but a considerably lower order according to the dentists' decisions. Scientific evidence indicates that molars in mesioangular and horizontal positions present a low risk and molars in distoangular position present the highest risk of developing pathologic conditions, compared with other angular positions.

Agreement between practitioners concerning removal of asymptomatic third molars

OBJECTIVE

To investigate and compare agreement within two groups of dental practitioners, family dentists and oral surgeons, in their decisions regarding removal of asymptomatic mandibular third molars.

SUBJECTS

Ten oral surgeons and 18 family dentists from South Wales with experience ranging from 5 to 28 years.

METHODOLOGY

Participants were presented with periapical radiographs of 36 asymptomatic, mandibular third molars and were informed of the age and gender of the patients and the degree of eruption of the third molars. Participants were asked to indicate whether they thought that the third molar should be removed or not. The degree of agreement between participants was measured by kappa indices for multiple raters.

RESULTS

The kappa indices were 0.14 for the oral surgeons and 0.09 for the family dentists, indicating poor agreement beyond chance. Although in most cases the participants decided not to remove the third molar, they did so inconsistently, that is, they did not make this decision on the same cases. There were also differences in the inclination of the participants to suggest removal of the 36 third molars.

CONCLUSION

Poor inter-observer agreement suggested that treatment decisions regarding asymptomatic third molars are based more on subjective beliefs and habitual practices than on rational decision making.

Clinical guidelines and self-assessment in dental education

This paper describes an educational programme where clinical guidelines are used in dental education and assesses the value of these guidelines as perceived by undergraduate students. It presents a comparison of students' own assessments of their performance with those of their instructors, according to such guidelines. The educational programme at the Faculty of Odontology, Lund University, is described through 3 main principles: problem-based learning, adoption of a holistic attitude to patient care and the promotion of oral health. The dental curriculum occupies 5 years comprising 10 semesters. 41, 5th semester students (16 male and 25 female) participated in the study. Students were introduced to guidelines in group discussions at the beginning of the semester. At the completion of a patient's planned course of treatment, the outcome was formally assessed both by students and clinical instructors. Performance was scored in various categories as "excellent", "acceptable" or "unacceptable" according to the standards defined. A total of 1373 scores were made by both students and instructors. 88% cent of students used the guidelines often or almost always and found them useful. Overall, no students received an "unacceptable" score and 40% of students achieved a score of "excellent". Female students tended towards a higher score, but this was not significant. Instructors' and students' scores agreed in almost 90% of instances. Students under-scored their performance more frequently than they over-scored it. It appears that the use of clinical guidelines may encourage an increased awareness of the decision-making processes involved in clinical practice, but it must be acknowledged that these guidelines are complex both in derivation and application.

Cartilage matrix macromolecules in lavage fluid of temporomandibular joints before and 6 months after diskectomy

The purpose was to investigate if antigenic fragments of aggrecan and cartilage oligomeric matrix protein (COMP) are detectable by enzyme-linked immunosorbent assay in lavage fluids from the temporomandibular joint (TMJ) and to examine if the relative content of these cartilage markers changes during development of osteoarthrosis (OA) after diskectomy. Lavage fluid was obtained at surgery and 6 months postoperatively in 13 patients. Computed tomography or magnetic resonance imaging was without evidence of hard-tissue changes prior to surgery in all patients. In 9 of the patients, sufficient material for analysis was obtained at both examinations. Aggrecan and COMP were detectable in all but 2 fluids, in which the COMP levels were below detection limit. The aggrecan/COMP ratio increased in all 9 patients during the 6-month period, indicating increased release of aggrecan relative to COMP fragments. The changed aggrecan/COMP ratio possibly reflects increased cartilage turnover during development of OA. Changes compatible with OA were present on computed tomography in all cases at the 6-month follow-up. This study shows that the lavage procedure is feasible for obtaining synovial fluid from the TMJ for immunochemical analyses of tissue-derived macromolecules.

Direct digital radiography for the detection of periapical bone lesions: a clinical study

The aim was to compare the observer performance of direct digital radiography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 patients, a conventional periapical radiograph using E-speed film was taken. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by seven observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightness set by the computer system. Following this, the observers were allowed to use the processing facilities for greyscale treatment. The results for original and processed direct digital images and for conventional radiographs were compared by Receiver Operating Characteristic (ROC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0.78 for processed images. Corresponding Az values were slightly higher, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Comparison between Az values showed no significant differences between conventional radiographs and original digital images, whereas the difference between Az values for original and processed digital images was still significant. It was concluded that conventional film radiography performed slightly better for the detection of periapical bone lesions than direct digital radiography and that image processing did not improve the observer performance.

Bone volume in human temporomandibular autopsy joints with and without erosive changes

The aim was to compare the trabecular bone volume (TBV) and the total bone volume (TOBV) of human temporomandibular joints (TMJ) with erosive changes with those of joints without erosive changes. We examined 35 TMJ autopsy specimens from 19 individuals aged 66 88 years. Sagittal sections of the joints were analyzed microscopically for erosive hard-tissue changes. The TBV and the TOBV of the sections were assessed with the aid of computerized image analysis. A significant increase in trabecular and total bone volume was found in condyles with erosive changes (TBV = 21%, TOBV = 54%) as compared with condyles without erosive changes (TBV = 15%, TOBV = 40%). The trabecular bone volume of the temporal component was also increased (TBV = 24%) in joints with erosive changes in the condyle as compared with joints with unaffected condyles (TBV = 16%). The findings indicate that the relative bone mass may play a role in the development of erosive changes in the TMJ.

Clinical and magnetic resonance imaging findings in temporomandibular joint disc displacement

OBJECTIVES

To describe the clinical and MRI findings in patients with disc displacement of the temporomandibular joint.

METHODS

Eighty-eight joints in 51 patients referred for suspected TMJ disc displacement were examined by MRI. Two oral radiologists assessed the images. The clinical findings were obtained by retrospective review of the patients' records.

RESULTS

Clicking was the most common clinical finding, present in 47 joints. Pain was reported for only 30 joints. Anterior disc displacement with reduction was found in 39 joints, anterior disc displacement without reduction in 31 joints, compound dislocations (anterolateral or anteromedial) in 13 joints and sideways displacement in 5 joints respectively. In about one-fourth of the joints, MRI revealed abnormal configuration of both disc and condyle. The osseous changes were subtle. Only 9% of the joints exhibited an osteophyte. Joint effusion in either the upper or the lower joint compartment was found in 19 joints. Out of 14 patients with joint effusion, six patients complained of pain from the TMJ region.

CONCLUSION

The most extensive soft and hard tissue changes were found in patients with anterior disc displacement without reduction. Pain was not a characteristic symptom for any type of disc displacement.

Trabecular bone pattern of the mandible. Comparison of panoramic radiography with computed tomography

OBJECTIVES

To analyse the possible correlation between the trabecular bone pattern of the edentulous mandible visualized by panoramic radiography and the bone mineral density (BMD) measured by computed tomography (CT).

METHODS

Panoramic radiography and CT were performed on 28 patients with edentulous mandibles. The trabecular bone pattern of 47 regions on the panoramic radiographs was classified into one of five grades. BMD was measured within circular regions of interest on the axial CT images in the corresponding trabecular area. The gradings were correlated with the CT values using one-way analysis of variance.

RESULTS

There was a significant correlation between the grade of the trabecular bone pattern and the BMD (P < 0.0001).

CONCLUSION

The proposed classification for the trabecular bone pattern on panoramic radiographs might be a useful aid for the evaluation of the edentulous mandible prior to implant placement.

Observer agreement in the assessment of mandibular trabecular bone pattern from panoramic radiographs

OBJECTIVES

To study the observer agreement in the assessment of trabecular pattern of the mandible from panoramic radiographs.

METHODS

Seven observers were asked to classify the trabecular pattern of 100 edentulous regions of the mandible in 80 randomly selected panoramic radiographs into one of five grades with the aid of a written description and reference images. Intra- and interobserver agreement was calculated as overall agreement and Kappa index.

RESULTS

The intra-observer agreement varied between 65% and 79%. The Kappa index for intra-observer agreement was moderate for three observers and substantial for four. For all seven observers, it varied according to the grade of trabecular bone pattern, but the majority deviated from each other by only one grade.

CONCLUSION

The relatively high rates of observer agreement indicate that panoramic radiography can be used for the clinical assessment of the trabecular pattern of the mandible.

Bone histomorphometry using interactive image analysis. A methodological study with application on the human temporomandibular joint

The aim was to develop a reproducible method for bone histomorphometry with the aid of a computerized image analysis program, and to examine the variation when assessing the total and the trabecular bone volume. Histologic sections of 18 temporomandibular joint autopsy specimens were read interactively using a cursor. The two parameters total bone volume and trabecular bone volume, of the condyle and the temporal component respectively, were estimated 2 x by 1 observer using 3 different threshold settings: an automatic, a semi-automatic and a manual technique. The threshold was based on the gray-scale distribution of the image. 2 observers read the same sections with the aid of the semi-automatic technique. The intra-observer variation expressed as coefficient of variation ranged between 1.9% and 7.1% for the different parameters, when the automatic threshold setting technique was employed, and between 2.8% and 8.7% with the semi-automatic technique. The manual technique resulted in a high intra-observer variation with a coefficient of variation between 5.2% and 19.9%. There was a systematic difference between the estimates of the 2 observers. In general, intra- and inter-observer variation was higher in the temporal component than in the condyle. The inter-section variation was moderate, the coefficient of variation ranging from 3.8% to 11.1%. The automatic and semi-automatic techniques resulted in comparable intra-observer variation, with a lower bias in the estimates of the semi-automatic technique. By letting one observer apply the semi-automatic technique, it was possible to achieve fast and reproducible analysis of the total and trabecular bone volume.

Judgement of removal of asymptomatic mandibular third molars: influence of position, degree of impaction, and patient's age

Our aim was to study general dental practitioners' (GDPs') and oral surgeons' judgement of the need for removal of asymptomatic mandibular third molars, described by three cues. The judges were also asked to estimate the development of pathologic conditions. There was considerable variance with regard to the individual judgements. As a group, GDPs estimated the need for removal to be higher for patients less than 40 years than those more than 40 years old. The oral surgeons estimated the need to differ for three different age groups. The GDPs estimated the need to be highest for distoangular molars and lowest for vertical molars, whereas the oral surgeons estimated these positions to be equal. Molars partially covered by soft tissue were given the highest priority for removal by both groups of judges. The mean proportion of variation explained by the three cues was high, except for tumor development, indicating that the judges used the cues and the combination of them to a great extent in their judgement of the risk for development of pathologic conditions.

Concavity of the posterior surface of the temporomandibular condyle: clinical cases and autopsy correlation

OBJECTIVES

To elucidate the significance of the radiographic finding of a concavity of the posterior surface of the temporomandibular condyle.

METHODS

Three clinical cases with a concavity were followed up clinically and radiographically. A total of 39 temporomandibular joint (TMJ) autopsy specimens were examined by corrected sagittal tomography and seven condyles with a concavity of the posterior surface found. They were analysed microscopically together with three joints with a normal, rounded condyle.

RESULTS

At follow-up tomography, two of the clinical cases revealed no change while the third patient had erosive changes after 7 months. The microscopic findings of the autopsy specimens varied. The articular cartilage in three of the seven joints with a concavity was similar to that in the normal condyles. The outer surface of the articular cartilage was sometimes uneven and the cartilage thickened, with an irregular junction between the articular cartilage and subchondral bone. In three joints the cartilage in the concavity had been replaced by granulation tissue. All seven joints had increased cellular activity in the concavity.

CONCLUSIONS

The radiographic finding of a concavity in the posterior surface of the condyle is not specific. When small and well-defined it is indicative of remodelling and of osteoarthrosis when larger and with a diffuse outline.

Evidence-based evaluation of three imaging methods for the temporomandibular disc

OBJECTIVES

To review the literature and evaluate the evidence for the diagnostic outcome of arthrography, computed tomography (CT) and magnetic resonance imaging (MRI) in the assessment of temporomandibular joint (TMJ) disc position.

METHODS

A literature search from 1978 to 1994 was conducted. Data on sensitivity, specificity, predictive values and likelihood ratios were collected and, if not available, calculated for each imaging method. Measures of observer performance were also recorded.

RESULTS

In total, more than 400 publications were retrieved on imaging of TMJ disc position, 219 on arthrography, 99 on CT and 147 on MRI, with a marked decrease in recent years. The majority of the publications (54%) presented series of patients. The diagnostic outcome cold be obtained from only 7% of the studies and the observer performance from only two of these. Arthrography had the highest diagnostic outcome for the diagnosis of anterior disc position; sensitivity 0.90, specificity 0.80, positive predictive value 0.88 and negative predictive value 0.82. Corresponding figures for CT were 0.66, 0.68, 0.66 and 0.74 and for MRI 0.86, 0.63, 0.67 and 0.83. The diagnostic outcomes expressed as the likelihood ratios for positive test outcome were 4.5 for arthrography, 2.3 for MRI and 2.1 for CT. The outcomes in diagnosing sideways and rotational displacements were higher for MRI (sensitivity 0.81, specificity 0.87, positive predictive value 0.82, negative predictive value 0.88) than for arthrography (0.64, 0.83, 0.70, 0.79). The likelihood ratios were 6.2 for MRI and 3.8 for arthrography. The interobserver performance ranged between moderate to substantial for arthrography and was almost perfect for MRI.

CONCLUSIONS

Based on current evidence on the diagnostic outcome, MRI seems to be the method of choice for diagnosing TMJ disc position. Arthrography has a higher diagnostic outcome for anterior disc position but the disadvantage of being an invasive method. We suggest that the quality of the evidence should be improved and that an analysis of the impact of the imaging methods on patient treatment should be performed.

Diagnostic accuracy of direct digital dental radiography for the detection of periapical bone lesions: overall comparison between conventional and direct digital radiography

OBJECTIVES

The diagnostic accuracy of direct digital radiography for the detection of small, experimentally made, periapical lesions was compared with that of E speed film. The high- and low-contrast resolutions of the imaging systems were also compared.

STUDY DESIGN

The high-contrast resolution was evaluated with a line pair plate. The low-contrast resolution was determined with a contrast-detail plexiglass phantom. To evaluate the diagnostic accuracy, the periapical region of dry human mandibles was examined. Receiver operating characteristic based on the readings of seven observers were generated.

RESULTS

The high-contrast resolution of the digital system was inferior, but the low-contrast resolution was comparable to that of E-speed film. For diagnostic accuracy no significant difference was seen between the areas under the receiver operating characteristic curves.

CONCLUSIONS

The quality of the direct digital images is comparable to that of E-speed film for the detection of periapical bone lesions.

Assessment of the trabecular pattern before endosseous implant treatment: diagnostic outcome of periapical radiography in the mandible

OBJECTIVES

To study the diagnostic outcome of periapical radiography in the assessment of the bone trabecular pattern of the mandible.

STUDY DESIGN

Mandibular autopsy specimens were radiographed. Seven observers assessed the radiographs with the aid of a proposed classification with and without reference images and the classification presented by Lekholm and Zarb. Accuracy was estimated on the basis of morphometric measurements of trabecular bone volume. Observer agreement was calculated as the estimated probability of agreement between and within observers and as kappa index.

RESULTS

With the classification proposed by us, the overall accuracy was 58% with and 50% without reference images. The accuracy for assessing dense trabeculation was higher (78%) than that for sparse trabeculation (28%). The accuracy of the proposed classification by Lekholm and Zarb was not possible to evaluate. The interobserver agreement varied between 49% and 64% and the intraobserver agreement between 75% and 86%.

CONCLUSION

A new classification with reference images is recommended to assess the trabecular pattern in periapical radiographs before implant treatment.

Pathoses associated with mandibular third molars subjected to removal

OBJECTIVES

To measure the prevalence of disease of mandibular third molars referred for removal and to estimate the risk for development of pathoses for two cues.

STUDY DESIGN

A prospective cohort study on molars subjected to removal was performed. The prevalence of different diseases and the patient's age, angular position, and degree of impaction of the molars were registered. Odds ratio for molars with different positions and impaction states were estimated.

RESULTS

Pericoronitis was found in 64% of cases, caries in the third molar in 31%, periodontitis in association with 8%, caries in the second molar in 5%, and root resorption of the second molar with 1% of the molars with pathoses. Odds ratio was highest for distoangular molars (5.8) and for molars partially covered by soft tissue (6.7).

CONCLUSIONS

The odds ratio is about 22 and 34 times higher for molars partially covered by soft tissue than for molars completely covered by soft or bone tissue. For distoangular molars the odds ratio is 5 to 12 times higher than for molars in other positions.

Global trends in oral and maxillofacial radiology education

Although the content of the undergraduate dental curriculum has evolved alongside the changes in dental practice, the methods and structure of the course have remained remarkably constant. In this article the recent developments in higher education are reviewed in depth and some changes in the pattern and setting of oral health outlined. Global trends in education in oral and maxillofacial radiology, with particular reference to undergraduate, postgraduate, and continuing professional education, are described against this background.

Temporomandibular joint disc position in arthrography. A descriptive analysis of the observer performance

OBJECTIVES

To explore the relationship between the use of diagnostic cues and observer performance in the diagnosis of the temporomandibular joint (TMJ) disc position.

METHODS

Thirty arthrographic examinations using fluoroscopy alone and combined with either transcranial radiography or tomography were selected. Seven observers assessed the examinations with the aid of reference images and written diagnostic cues for three disc diagnoses. After one month three of the observers repeated the assessments and noted how they applied the diagnostic cues. Later, they made a consensus report on how the cues were applied to each joint.

RESULTS

The seven observers agreed unanimously with the reference diagnosis by fluoroscopy alone in 11 joints and in 14 when supplemented with transcranial radiography or tomography. Seven joints were given three different diagnoses by the seven observers when fluoroscopy was used alone and five when supplemented with transcranial radiography or tomography. The cues were applied with confidence in those joints where the observers were unanimous but in those with three different diagnoses, the anatomical features described in the cues were difficult to identify or the findings were ambiguous as they did not match the cues.

CONCLUSIONS

It appears difficult to define radiographic cues applicable to all TMJ disc positions.

Microscopy and tomography of erosive changes in the temporomandibular joint. An autopsy study

Thirty-nine temporomandibular joint autopsy specimens were examined by microscopy and tomography for erosive changes. We found two types of erosive changes, an extensive type with complete loss of cartilage and a local type with retained articular cartilage. On microscopic examination nearly twice as many temporal components as condyles were eroded. The erosions were generally more extensive in the condyle. Erosions in the condyle were evenly distributed. In the temporal component there was a slight predominance of erosions located to the lateral part of the tubercle. The radiologic investigation underestimated both the presence and the extent of the erosions. Positive predictive values and negative predictive values were 0.70 and 0.83, respectively, for erosions in the condyle and 0.91 and 0.68 for erosions in the temporal component. It is suggested that the initial event in osteoarthrosis of the TMJ can occur as a subarticular hard-tissue change. The need for more accurate diagnostic tools than radiography should be stressed.

Corrected sagittal tomography of the temporomandibular joint. Influence of errors in film and patient positioning on linear and angular measurements

The aim of this study was to assess the variation in film and patient positioning in horizontally corrected sagittal tomography of the temporomandibular joint (TMJ). The influence of this variation on linear and angular measurements of some anatomic structures of the TMJ was also studied. There was no significant variation in film positioning in the tomograph, using a multi-film cassette. The variation in positioning the patient in the tomograph was significant when four dental assistants were asked to place the Frankfort plane parallel to the horizontal plane. The measurements with the film in a straight position were compared with the measurements with the film angulated, to simulate the mean variation in film and patient positioning. Linear and angular measurements of anatomic structures were performed in arthrotomograms of 58 joints, representing joints with superior disk position and joints with anterior disk position with and without reduction. There was a difference between the two measurements for four different distances and one angle independent of diagnosis. No differences could be found between patients belonging to the different diagnostic groups. The results indicate that variation in patient positioning influences linear and angular measurements of anatomic structures in TMJ arthrotomograms.

Follow-up examination of the temporomandibular joint disk after splint therapy by magnetic resonance imaging--a case report

A 38-year-old female patient presented with temporomandibular joint (TMJ) pain, bilateral clicking and intermittent locking. The patient was treated with a splint in order to decrease the symptoms and to obtain a proper disk-condyle relationship. The effect of the splint therapy was investigated after one month and after one year and five months using magnetic resonance imaging (MRI) with splints in place. After treatment for one year and six months, the clicking sound of the right TMJ disappeared, and she became free from locking. With the aid of MRI, it was found that the disk of the right TMJ had changed from an anterior position with reduction to a superior position. In the left TMJ, the disk changed from an anterior position without reduction to an anterior position with reduction. MRI gave important information on the disk position and the efficacy of the splint therapy.