General and local predictors of mandibular cortical bone morphology in adult females and males: the seventh survey of the Tromsø Study

Objectives To analyze factors predicting mandibular cortical width (MCW) and mandibular cortical index (MCI) in adult females and males. Material and methods Data on 427 females and 335 males aged 40–84 from The Tromsø study: Tromsø7 were used. T-score, age, menopausal status (for females), remaining teeth, and periodontal status were analyzed in linear and logistic regression analyses as predictors of MCW and MCI, respectively. Results T-score, age, and the number of remaining teeth significantly predicted MCW in females but not males. Standardized β coefficients were 0.286, −0.231, and 0.131, respectively. The linear regression model explained 24% of MCW variation in females. MCI in females was significantly predicted by T-score, age, and remaining teeth with the Wald values of 9.65, 6.17, and 5.83, respectively. The logistic regression model explained 16.3−23% of the variation in MCI in females. In males, T-score was the only significant predictor of the eroded cortex, and the logistic model explained only 4.3–5.8% of the variation in MCI. Conclusions The T-score demonstrated a stronger relationship with MCW and MCI than other factors in females, which supports the usefulness of those indices for osteoporosis screening. Conversely, the T-score exhibited no association with MCW and remained the only significant predictor of MCI in males, yet to a lesser extent than in females. Clinical relevance Understanding factors affecting mandibular cortical morphology is essential for further investigations of MCW and MCI usefulness for osteoporosis screening in females and males

Automatic detection of the mental foramen for estimating mandibular cortical width in dental panoramic radiographs: the seventh survey of the Tromsø Study (Tromsø7) in 2015-2016

Objective To apply deep learning to a data set of dental panoramic radiographs to detect the mental foramen for automatic assessment of the mandibular cortical width. Methods Data from the seventh survey of the Tromsø Study (Tromsø7) were used. The data set contained 5197 randomly chosen dental panoramic radiographs. Four pretrained object detectors were tested. We randomly chose 80% of the data for training and 20% for testing. Models were trained using GeForce RTX 2080 Ti with 11 GB GPU memory (NVIDIA Corporation, Santa Clara, CA, USA). Python programming language version 3.7 was used for analysis. Results The EfficientDet-D0 model showed the highest average precision of 0.30. When the threshold to regard a prediction as correct (intersection over union) was set to 0.5, the average precision was 0.79. The RetinaNet model achieved the lowest average precision of 0.23, and the precision was 0.64 when the intersection over union was set to 0.5. The procedure to estimate mandibular cortical width showed acceptable results. Of 100 random images, the algorithm produced an output 93 times, 20 of which were not visually satisfactory. Conclusions EfficientDet-D0 effectively detected the mental foramen. Methods for estimating bone quality are important in radiology and require further development

Procedure time and filling quality for bulk-fill base and conventional incremental composite techniques—A randomised controlled in vitro trial

Objectives: The aims of this randomised controlled laboratory trial were to determine the procedure time and immediate quality (surface porosity and marginal gaps) of fillings placed using the bulk-fill base technique and the conventional incremental technique in simulated clinical settings. Methods: Forty-two dentists and dental students were randomly allocated to use either the bulk-fill base technique or the conventional incremental technique to fill an identical class II disto-occlusal cavity in a maxillary left first molar typodont tooth. We recorded the time the participants used to fill the cavity and evaluated the surface porosity and marginal gaps on the approximal surfaces of the fillings using a stereomicroscope and specific probes according to the FDI criteria for restoration evaluation. Data were analysed using the Mann–Whitney U, Kruskal–Wallis, and chi-square tests. Results: The median time ± interquartile range was 186 ± 80 s for the bulk-fill base technique and 463 ± 156 s for the conventional incremental technique (p < 0.001). The quality of the fillings was better for the bulk-fill base technique than for the conventional incremental technique (X2 = 9.5, p = 0.002). Neither operator experience nor the usual technique of choice were associated with the procedure time or the quality of the fillings. Conclusions: Compared to the conventional incremental technique, the use of the bulk-fill base technique shortened the time to fill a cavity by 59.8 % or 4 min and 36 s, and it improved the immediate surface and marginal quality of the fillings, regardless of the operator’s experience or technique preference. Clinical significance: The use of the bulk-fill base technique instead of the conventional incremental technique leads to significant time-savings when placing large class II composite fillings. Additionally, the use of the bulkfill base technique instead of the conventional incremental technique improves the immediate quality of large class II composite fillings

Magnetic resonance imaging in patients with temporomandibular disorders and pain

Magnetic resonance imaging (MRI) is the method of choice for imaging disorders of the temporomandibular joint (TMJ) in patients with temporomandibular disorders (TMD) and pain. But the method is expensive, and wait times for MRI exams of the TMJ are long. So an evaluation of the diagnostic and therapeutic efficacy of MRI of the TMJ is valuable when estimating the imaging method’s use in treatment decisions and prognosis. To reduce cost to society, individual selection criteria for MRI of the TMJ need to be defined. The aim must be to minimize unnecessary examinations and to restrict use of MRI to patients who will benefit from the examination. To evaluate evidence for the efficacy of MRI in patients with TMD and pain, a systematic review of the literature was done (article I). The search yielded 494 titles, of which 22 were relevant. No publication had a high level of evidence; 12 and 10 publications had moderate and low levels of evidence, respectively. The evidence grade for diagnostic efficacy expressed as sensitivity, specificity, and predictive values was insufficient. No publication on diagnostic thinking efficacy or therapeutic efficacy met the inclusion criteria. The TMJs of 60 TMD patients were examined with MRI (article II). The patients were placed in one of two clinical diagnostic groups—(1) myofascial pain or (2) arthralgia/osteoarthritis—per the Research Diagnostic Criteria for TMD (RDC/TMD), a diagnostic classification system. This classification is widely used internationally, but further validation and development is needed. The most common MRI findings were various kinds of disc displacements; structural bone changes; and joint fluid, which occurred in both pain groups. The MRI findings did not support the RDC/TMD clinical diagnoses. In a randomized controlled trial of 80 patients suffering from TMD pain (article III), the short-term efficacy of a resilient appliance was compared with a control appliance consisting of a non-occlusal hard acrylic palatal appliance. After 10 weeks of treatment, 61% in the treatment group and 46% in the control group had at least a 30% reduction in TMD pain. Differences between groups were nonsignificant. Changes in condyle and disc position could be factors that are affected by appliance therapy and influence treatment outcome of TMD patients. MRI of the TMJ was performed in 48 of the 80 patients (article IV). The results showed that treatment outcome was not related to MRI-determined changes in condyle and disc position

The efficacy of magnetic resonance imaging in the diagnosis of degenerative and inflammatory temporomandibular joint disorders : a systematic literature review

Objective. To evaluate the evidence for the efficacy of magnetic resonance imaging (MRI) in the diagnosis of disk position and configuration, disk perforation, joint effusion, and osseous and bone marrow changes in the temporomandibular joint. Study design. A PubMed literature search with specific indexing terms and a hand search were made. Two reviewers assessed the level of evidence of relevant publications as high, moderate, or low. Based on this, the evidence grade for diagnostic efficacy was rated as strong, moderately strong, limited, or insufficient. Results. The literature search yielded 494 titles, of which 22 were relevant. No publication had a high level of evidence, and 12 had moderate and 10 low levels of evidence. The evidence grade for diagnostic efficacy expressed as sensitivity, specificity, and predictive values was insufficient. Conclusion. That evidence is insufficient emphasizes the need for high-quality studies on the diagnostic efficacy of MRI, incorporating accepted methodologic criteria

Resilient appliance-therapy treatment outcome in patients with TMD pain correlated to MRI-determined changes in condyle position

The aim of this research was to study if changes in condyle position in temporomandibular disorders (TMD) patients could be a factor that is affected by resilient appliance therapy and if it influences the treatment outcome. The study investigated 48 patients randomly assigned to a treatment group (T group = 21 patients, using resilient appliance) or a control group (C group = 27 patients, using nonoccluding appliance). Changes in the condyle-fossa relationship (with and without the appliance) were determined in an MRI examination. Ten weeks after treatment, the treatment outcome was measured. The results showed that with the appliance, change in condyle position occurred in 76% of the T group and 22% of the C group (p < 0.001). Sixty-seven percent (67%) of the T group and 44% of the C group experienced a successful treatment outcome. Treatment outcome was not related to changes in condyle position in patients with TMD pain

Short-term treatment of a resilient appliance in TMD pain patients : a randomized controlled trial

To investigate the short-term efficacy of a resilient appliance in patients with temporomandibular disorders (TMD) suffering from pain, a randomized, controlled trial was performed in 80 recruited TMD pain patients. They were randomly allocated to one of two groups: treatment with a resilient appliance or treatment with a hard, palatal, non-occluding appliance. The primary treatment outcome measure was judged positive when patients' TMD pain at worst, according to the Visual Analog Scale (VAS), decreased by at least 30%. One additional treatment outcome was reduction of characteristic pain intensity. Number needed to treat was measured on the basis of primary treatment outcome at 10 weeks. At baseline, patient characteristics and TMD pain did not differ between the groups. There were no significant differences between groups regarding a 30% reduction in VAS-reported TMD pain at worst at 10 weeks' follow-up; 61% in the treatment group and 46% in the control group. After 6 and 10 weeks of treatment, CPI decreased in both groups. Number needed to treat was 9.1 for both the resilient and the control appliance therapy during 10 weeks. There was no statistically significant difference between the resilient appliance and the non-occluding control appliance in reducing TMD pain from a short-term perspective

Clinical diagnoses and MRI findings in patients with TMD pain

The aim of this study was to correlate clinical diagnoses in temporomandibular disorders patients suffering from pain diagnosed as arthralgia/osteoarthritis or myofascial pain according to the Research Diagnostic Criteria for temporomandibular disorders with findings made on magnetic resonance imaging. The temporomandibular joints of 60 consecutive patients, 41 with arthralgia/osteoarthritis and 19 with myofascial pain, were examined clinically and with magnetic resonance imaging. The most common magnetic resonance imaging findings were disc displacements and structural bone changes, which were found in both pain groups. However, disc displacements were found significantly (p = 0.002) more often in the arthralgia/osteoarthritis group. 104 joints were found to have no clinical diagnosis of disc displacements, but 64 of these joints had findings of disc displacements on magnetic resonance imaging. Joint fluid was found both in the arthralgia/osteoarthritis group (20 patients) and in the myofascial pain group (5 patients). Patients having a combination of disc displacement and joint fluid were significantly (p = 0.047) more common in the arthralgia/osteoarthritis group. In conclusion, the magnetic resonance imaging findings of disc displacement and structural bone changes were common in temporomandibular disorders patients with pain of both myogenous and arthrogenous origin. The clinical diagnoses for subdivision into myogenous and arthrogenous pain groups were not confirmed by magnetic resonance imaging