RATIONALE:Obesity is a major risk factor towards the development of obstructive sleep apnea, while significant weight loss (both conservatively managed and surgically assisted) has a variable effect upon its severity. Differences in the effect of weight loss on obstructive sleep apnea may be due to underlying craniofacial characteristics. OBJECTIVES:To determine whether craniofacial characteristics can predict OSA treatment response to significant weight loss. METHODS:We analyzed craniofacial measurements from lateral cephalograms performed at baseline on 57 patients enrolled in a previously reported 2-year randomized clinical weight loss trial (laparoscopic adjustable gastric band surgery versus conservatively [dietician and very low calorie diet] treated). Group mean weight loss was ∼ 13% (mean weight loss 131 to 114 kg), with corresponding reduction in mean apnea-hypopnea index (AHI) from 61 to 41 events/h. Computer assisted lateral cephalogram analysis was undertaken by three trained staff blinded to treatment. We analyzed lateral cephalogram and demographic data at baseline (cross-sectional) and change over two years (interventional) in 54 patients. MEASUREMENTS AND MAIN RESULTS:Baseline cross-sectional analysis indicated no cephalometric measurement correlated significantly with baseline AHI when corrected for neck circumference. The percentage change in AHI over 2 years correlated with a shorter menton-gonion distance (i.e., mandibular body length). The % change in AHI correlated with the % weight change (R(2) = 0.25, p < 0.001) and mandibular body length (R(2) = 0.19, p = 0.002). The % change in AHI correlated with combined weight change and mandibular body length (combined R(2) = 0.31, p < 0.001). CONCLUSIONS:Weight loss as a therapeutic option for severe OSA with severe obesity may be predicted by shorter mandibular body length as measured by lateral cephalometry.

Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty-two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio-bucco-lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one-third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF.

AIM:To determine the influence of clinical experience on the accuracy and consistency of estimation of radiographic working length (WL) for the root canal treatment of single-rooted teeth.METHODOLOGY:Forty conventional WL periapical radiographs that included variations in file length were selected. They were digitally scanned and arranged in PowerPoint presentations on CDs. These were distributed to three assessor groups; fourth-year undergraduates at two stages of training (Groups 1 and 2) and endodontic postgraduates (Group 3). Participants were asked to determine the adjustment needed in millimetres to position the file tip at the correct WL for each image. A gold standard file position was provided by three experienced endodontists. For inter-group comparison of scores, the Kruskal-Wallis, ANOVA and post hoc Bonferroni tests were used. Evaluation of intra-examiner consistency was with the Kappa test. To evaluate intra-group consistency, the Wilcoxon signed rank test was used to compare the frequency of weighted correct scorings.RESULTS:File adjustments of Group 3 were significantly more accurate than those of Group 1 (P = 0.006). The scores of Group 3 were also better than those of Group 2, although the difference was not significant. When the scores of the undergraduate groups were compared, the difference was not statistically significant. The consistency of the groups was not affected by a 2-week pause between assessments, and no definite pattern could be detected across any of the groups with the Kappa test.CONCLUSION:Clinical experience after graduation influenced the accuracy of estimating the adjustments needed for correct radiographic WL of single-rooted teeth. The most experienced group was significantly more accurate than the other groups.

AIMS:To compare a monotherapy of Er:YAG laser debridement (ERL), wavelength 2940 nm, with mechanical scaling and root planing (SRP) for the treatment of chronic periodontitis using clinical and patient-centred outcomes.METHODS:Twenty-eight participants had two randomly assigned quadrants treated with ERL and two with SRP. Full-mouth plaque index, probing depth, bleeding on probing, clinical attachment level and gingival recession were recorded at baseline and 6- and 12-weeks post therapy. A questionnaire was used to assess pain, discomfort and satisfaction during and after treatment.RESULTS:Twenty-two participants completed treatment and had 6- and 12-week clinical re-evaluations. SRP provided greater mean pocket depth reduction at 6- and 12-weeks (p = 0.01 and p = 0.003 respectively), and a greater reduction in pockets ≥ 4 mm at 6 weeks only (p = 0.03) compared with ERL. SRP also resulted in a significant reduction in bleeding on probing (BOP) sites at 12 weeks compared with ERL and a statistically significant greater reduction in mean clinical attachment level (CAL) at 6- (p = 0.02) and 12-weeks (p = 0.03). Patients expressed greater satisfaction with SRP on the day of treatment but were equally satisfied subsequently.CONCLUSION:SRP resulted in a statistically significant greater short-term improvement in clinical parameters and patient satisfaction compared with ERL.

The purpose of the study was to determine the effect of removing or modifying the smear layer on the indication provided by the Prepometer pulp proximity-indicating instrument. Third molars were prepared to produce flat surfaces in the coronal dentine, and control Prepometer LED readings were made. Group E was treated with 18% EDTA and Group T with Tubulicid. Prepometer readings were repeated. Dentine was removed in 0.5 mm increments, and readings repeated until a red LED appeared, indicating a danger of pulp exposure. Distances to the pulp were measured. t test, Wilcoxon signed ranks test (WSR) and ordinal regression (OR) analysis were performed, together with SEM examination. There were significant differences between both test groups and their untreated controls. OR showed that a red LED appeared further from the pulp with EDTA treatment than with no treatment. A red LED appeared closer to the pulp with Tubulicid treatment than with no treatment. SEM showed smear removal in Group E and occlusion of tubules in Group T. Prepometer performance was significantly influenced by treatment with EDTA and Tubulicid. Practitioners would be required to learn to interpret the display of the Prepometer instrument in the context of the tooth under treatment and the surface condition of the cut dentine.

AIMTo: (i) compare laser Doppler pulpal blood flow (PBF) signals from restored and unrestored first molar teeth, (ii) investigate PBF in teeth with large and small restorations, and (iii) to relate PBF to pulp chamber dimensions on radiographs.METHODOLOGYBitewing radiographs of young adults with restored first molars were obtained and pulp chamber dimensions measured. Subjects were divided into 2 groups: group A with a restored tooth and an unrestored contralateral (43 subjects) and group B, those with a molar with a small (usually occlusal) restoration whilst the contralateral tooth had an extensive occlusal restoration (or restorations) or restored proximal surface(s) and/or cuspal overlay (31 subjects). The 148 teeth responded to electric pulp testing, and their PBF was recorded using a laser Doppler flowmeter. Data were analysed using Student's t-test.RESULTSIn group A the PBF in the restored teeth was significantly lower than in unrestored contralaterals (P = 0.028) and the total pulp chamber area and that in the clinical crown were smaller (P = 0.039 and 0.021 respectively). The group B molars with large restorations had significantly lower PBF than contralaterals with small restorations (P = 0.001), and their total pulp chamber area and pulp chamber width at cervix were reduced significantly (P = 0.003 and 0.032 respectively).CONCLUSIONSIn molars the size of the pulp chamber was influenced by the presence of restorations and the PBF was reduced when restorations were present. Size and extent of restorations had a significant effect on PBF.

The aim was to determine whether extracted teeth could be used to test the Prepometer instrument, which indicates pulp proximity with green/amber/red light emitting diodes. Third molars were reduced to a plane in dentine and Prepometer readings made. Dentine was removed in 0.5 mm increments and readings made until only lights 9 or 10 (red) showed. The teeth were sectioned and the dentine thickness measured. Analysis permitted construction of a highly significant predictor-model (p < 0.01), the red/amber light boundary coinciding with a dentine thickness of 2.4 mm. The Prepometer was consistent in predicting pulp proximity but was more sensitive than specified.

Twenty volunteers with first molars free of restorations and caries were recruited. One molar from each arch was selected, and rubber dam was applied. Seven sites on each crown were electric pulp tested 4 times with an Elements Diagnostic Unit, and lowest threshold responses were recorded. Data were analyzed with one-way analysis of variance and the Tukey test at the .01 level. The lowest response for both the maxillary and mandibular teeth was with the probe on the mesiobuccal cusp tip. Other sites showed an increase in level from the mesiobuccal cuspal surface, mesiobuccal gingival surface, and the center of the supporting cusps (palatal of maxillary molar, buccal of mandibular molar). No significant difference in responses was found between male and female subjects; however, male subjects responded at higher thresholds than female subjects on all test sites except the mesiobuccal cusp tip. The optimum site for pulp testing first molars is the mesiobuccal cusp tip.

The aims of this study were to evaluate the prevalence, risk and odds ratios of gingival recession defects associated with elective lip piercing and wearing of stud jewelry, and to attempt to identify risk factors that might permit the incidence of recession and its severity to be predicted, using Miller's classification. Ninety-one subjects with lip piercing and labrets were evaluated with regard to gender, age, smoking history, orthodontic history, and labret characteristics. An age-matched group of 54 individuals without peri-oral piercing provided the control. Gingival recession was recorded on teeth opposing a labret in 68.13% of pierced subjects. By contrast, only 22.2% of unpierced individuals demonstrated recession. The odds ratio between pierced and control groups indicates a likelihood of recession 7.5 times greater in a pierced individual wearing a labret than in an unpierced individual. Logistical regression analysis showed that age, gender, smoking and labret configuration did not significantly influence the development of recession. Furthermore, an illustrative example indicates that piercing and provision of a labret might typically increase the risk of recession occurring from 34.4% (pre-piercing) to 80.8 %. Recession severity was greater in the pierced group, with Miller's class 2 and 3 defects observed in 18.7% of the pierced but not at all in the unpierced group. Ordinal regression identified previous orthodontic treatment as the only significant predictor of Miller's grade. We concluded that a clear link exists between lip piercing, labret use and gingival recession. Belief that labret placement and configuration can be modified to provide protection is unfounded.

Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The aim of this study was to determine the prevalence of approximal caries in an educated young adult (New Zealand dental student) population, and to compare the diagnostic decisions of students and university teachers. A total of 123 students aged from 18 to 25 years (mean age 21 years) participated, having given their informed consent. Their bitewings were digitised and assessed for approximal carious lesions from the distal surface of the first premolars to the mesial surface of the second molars on the same computer screen. The following criteria were used: (0) no detectable radiolucency, (R1) lesion confined to the outer half of the enamel, (R2) lesion into the inner half of the enamel, (R3) lesion into the outer half of dentine along the amelodentinal junction, (R4) lesion beyond the outer part of the dentine. The views were assessed by two final-year dental students and two experienced university teachers, and results were compared. A total of 2710 surfaces were examined; restored and missing surfaces (tooth absent, off film or surface unreadable) were excluded. Carious lesions were found in 173 (6.38 percent) of the surfaces. Only 57 subjects presented with carious lesions radiographically, but 16 (13 percent) of subjects had 87 percent of all the lesions. Seventy-nine percent of the lesions were enamel lesions (R1 and R2), with 21 percent of the lesions having dentine involvement (R3 and R4). Inter-examiner agreement was high, Pearson's correlation coefficient r = 0.8237, and Cohen's kappa kappa = 0.76.

The aim was to determine whether radiographs provide a clinically useful indication of pulp size in diseased/restored human first molar teeth, and to investigate accessibility of pulp tissue for diagnostic testing using laser Doppler flowmetry (LDF). Extracted teeth of known age were collected. Restorative materials were removed and teeth with evidence of pulp exposures excluded. Fifty-six teeth were radiographed from buccal and mesial aspects, and then their crowns were sectioned axiobuccolingually and photographed. Images were digitally scanned and measurements made of the total pulp area (above a line across the most superior part of the pulpal floor) and the pulp area in the clinical crown (superior to a line between the amelocemental junctions). The pulp width at the cervix and the highest point of the pulp were also recorded. Data were analysed using Pearson correlations. Pulp areas within the clinical crowns were significantly larger than indicated by radiographs, by 23% in the case of the clinically attainable buccal view (P < 0.05). Pulps may be more accessible to flowmeter testing than they appear. Absence of pulp tissues in the crown was recorded in equal numbers of teeth on radiographs and sections, but with agreement for only one tooth. Sixteen per cent of the teeth had no pulp area in the clinical crown when sectioned, but might still be suitable for testing using LDF.

Purpose: Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships in individuals using mandibular advancement devices for obstructive sleep apnea are beginning to appear. This study sought cephalometric means of identifying such individuals before commencing therapy. Materials and Methods: Cephalograms of 34 obstructive sleep apnea sufferers who had worn mandibular advancement devices for 2 years were compared retrospectively with baseline films taken at commencement of therapy and analyzed for signs of morphologic changes in jaw position and occlusal relationship. In affected patients, two distinct morphologic species of mandibular reposturing became evident: (1) bilateral posterior open bite with destructive incisal attrition; and (2) less destructive intermediate open bite over the premolar and first molar regions. From the observed morphology patterns, gonial angle and maxillary-mandibular plane angle were analyzed as possible vertical cephalometric risk predictors, with newly defined pterygoid advancement proportion (PtAP) as a horizontal predictor. Results: Three patients displayed the posterior open bite pattern and had gonial angles less than or equal to 119 degrees and maxillary-mandibular plane angles less than or equal to 16 degrees, with PtAP values greater than or equal to 0.48. Prediction intervals for the five intermediate open bite cases were 118 degrees less than or equal to gonial angle less than or equal to 128 degrees, and 23 degrees less than or equal to maxillary-mandibular plane angle less than or equal to 32 degrees. PtAP values were greater than or equal to 0.52. Conclusion: Cephalometric analysis can help practitioners identify which apnea patients might be likely to develop irreversible mandibular postural changes from wearing a jaw-repositioning device.

Molar crown preparations, as described in the literature, have standard forms dictated by the demands of retention, resistance and the physical properties of materials. Standard designs may not be appropriate for all patients because of ethnic variations in tooth shape, pulp size and dentine thickness. Accurate data on these features could assist clinicians to minimize the risk of accidental pulpal injury. The aim of this study was to compare the first molar crown and pulp dimensions between Asian (Chinese, Korean, Malay) and other ethnic groups, using measurements from the bitewing radiographs of 121 subjects. Comparisons revealed the following significantly different features of Asian first molars: larger total pulp areas in uppers (P < 0.0005); shorter crowns (P < 0.0005); narrower upper teeth at the cervix (P < 0.0005); wider pulps at the cervix of lowers (P < 0.02); more bulbous crowns (P < 0.0005 for uppers; P < 0.01 for lowers), and finally significantly thinner dentine interproximally at the cervix (P=0.001 for uppers; P=0.011 for lowers). Preparations with wide shoulders could pose hazards to the pulps in Asian subjects. This study emphasizes the value of bitewing films in assessing crown and pulp size and shape before making crown preparations. The experienced practitioner may intuitively include tooth and pulp morphology in treatment planning, but this appears not to be taught or documented in textbooks.

AIM:To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of restorations on pulp size; (iii) determine differences in dimensions between teeth of Mongoloid patients and teeth of other ethnic groups; and (iv) record the presence of pulp stones.METHODOLOGY:Bitewing radiographs of 121 subjects (mean age, 20.9 years) were taken under standardized conditions. The films were digitally scanned and nine measurements were made from the image of each first molar. The data were analysed in terms of presence or absence of restorations and in terms of racial group. Differences were examined using Student's t-test, Pearson correlations and Levene's test.RESULTS:A total of 445 teeth were analysed. Large crowns were correlated to large pulps. Teeth restored with occlusal and proximal restorations had significantly smaller pulps (P = 0.044 and 0.004, respectively), but no difference was found in pulp area in the clinical crown between the restoration types. Mongoloid crowns were shorter and more bulbous. Pulp areas of maxillary molars and pulp widths at the cervix of mandibular molars were significantly larger in Mongoloids. The pulp area in the clinical crown correlated to pulp horn height for Mongoloids and others and for maxillary and mandibular teeth. No differences were found between the heights of pulp horns in the Mongoloid and other teeth. Four of the pulp measurements demonstrated sexual dimorphism. Stones were present in almost 10% of the subjects, representing 4% of the tooth pulps examined.CONCLUSION:Even teeth with shallow occlusal restorations had reduced pulp spaces. There were significant differences in pulp and crown dimensions between the teeth of Mongoloid patients and those of other patients.

STATEMENT OF PROBLEM:With the use of multimedia electronic knowledge as a tool in dental education, an overriding concern has centered on how to devise an organizational model that will accommodate the vast and diverse arrays of information involved, yet be sufficiently simple enough to provide students with a rational and consistent means of accessing the information they require. By adopting the natural history of the diseases dentists are called on to address as a common organizing principle, it becomes possible to link all concepts that relate to individual problem areas through a technique of retro-mapping. PURPOSE:The purpose of this article is to introduce learners to a cognitive "scaffolding" that will assist them in achieving a deeper cognitive dimension for problem solving.

STATEMENT OF PROBLEM:In using multimedia electronic knowledge-transfer as a tool in dental education, an overriding concern has centered on how to devise an organizational model that will accommodate the vast and diverse arrays of information involved, yet be sufficiently simple to provide students with a rational and consistent means of accessing the information they require.PURPOSE:This article presents a model that adopts the Natural History of Dental Diseases as the organizing principle. This article also encourages a mindset in prosthodontics that focuses on the dynamics of energy-dispersal through the supporting structures, in an attempt to provide learners with a deeper cognitive dimension for problem solving and to facilitate their empowerment as life-long learners.

UNLABELLED:Increasing life expectancy, age related reduction in adaptability and progressive severe mandibular resorption all add to the importance of any factor improving the prosthetic success.OBJECTIVE:To investigate the effect of two different lingual shapes of lower dentures on patients' ability to resist lifting forces.DESIGN:Tongue pressures on the lingual surface of complete mandibular experimental dentures were recorded from mid-line, premolar and molar transducers. Two experimental prostheses were fabricated for each subject: one conventionally contoured, the other formed by piezography.SETTING:A clinical research laboratory.SUBJECTS:Five experienced complete denture wearers between age 64 and 82 years.INTERVENTION:Lifting forces were applied at the midline, left and right premolar sites in random order.MAIN OUTCOME MEASURES:Peak resistance to lifting forces and lingual pressures used during these tests.RESULTS:Lingual pressures exerted anteriorly were dramatically higher than those on premolar and molar surfaces. Significantly higher pressures were used to resist lifting forces applied to piezographically than conventionally formed contours; correspondingly, significantly higher lifting peak forces were, on average, resisted.CONCLUSIONS:Providing a lower denture with a piezographically produced lingual surface was shown, in this preliminary study, to enhance tongue retentive ability over a conventional design. It seems reasonable to maximise retentive potential with oblique sublingual polished surfaces and minimise the adaptive demand, particularly for older patients, by using a piezographic technique which "customises" the contour and precludes over-extension.

Implant-supported prostheses must be able to withstand the load capabilities of individual patients to overload them. The gold alloy screw in the Brånemark system is by intention the weakest component. Therefore, if cantilever lengths can be designed so that occlusal forces distributed to individual fixtures are limited to the gold screws' ability to accept them, breakage-free performance may be assured. Models, such as that of Skalak, are capable of developing the required analytical processes to provide the information necessary to achieve this design. Unfortunately, the overt mathematical complexity of the Skalak model has militated against its routine use in the operatory. Its computational aspects are, however, eminently suited to computerization and indeed provide the basis for the computer program that is described in this article. This program is simple to apply clinically and, when used in conjunction with available load parameters of gold screw performance, can provide the clinician with a routine and scientific basis for rational implant prosthesis design.