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.

Double vs single primary tooth extraction in interceptive treatment of palatally displaced canines.

OBJECTIVES: To compare the impact of primary canine and primary first molar extractions with extractions of only the primary canine regarding correction of palatally displaced canines (PDCs). MATERIALS AND METHODS: Thirty-two children aged 9.5-13.5 years with 48 PDCs were randomly allocated to either the double-extraction group (DEG) or single-extraction group (SEG). Clinical and radiographic examinations were performed at baseline and at 6-month intervals until the canine emerged or orthodontic treatment was started. Outcome measures were: emergence of maxillary canine (yes/no), emergence of maxillary canine into a favorable position (yes/no), and maxillary canine positional change (angulation and sector). Factors influencing PDC emergence were analyzed using logistic regression. RESULTS: In the DEG, 64% (16/25) of canines emerged into the oral cavity vs 78% (18/23) in the SEG (P = .283). Favorable PDC position at trial end was seen in 64% (16/25) of the DEG vs 57% (13/23) of the SEG (P = .600). Significant distal movement of PDCs was recorded in the DEG and SEG, though no significant difference was observed between groups. Significant predictors of canine emergence were initial canine angulation (Angle A) (P = .008) and space conditions at T0 (P = .030). CONCLUSIONS: Double or single primary tooth extraction procedures are equivalent in supporting PDC eruption into the oral cavity and into a favorable position in the dental arch. Initial canine angulation and space assessments may be used as predictors of successful PDC eruption.

Perceived Stress and Associated Factors in Russian Medical and Dental Students: A Cross-Sectional Study in North-West Russia.

The aim was to assess perceived stress (PS) and factors associated with PS in Russian medical and dental students. A total of 406 medical and 283 dental students aged 18-25 years that attended the Northern State Medical University in Arkhangelsk, North-West Russia participated in this cross-sectional study. A structured, self-administered questionnaire was used to collect information on socio-demographic and socioeconomic factors, oral health (OH) behavior, and self-reported OH. All students were clinically examined to assess dental caries, oral hygiene, and gingiva. PS was measured by the Perceived Stress Scale 10 (PSS-10). Of the students, 26.0%, 69.1%, and 4.9% reported low, moderate, and high PS, respectively. Female sex (b = 2.28, 95% confidence interval (CI): 1.38-3.18), dental faculty (b = 1.74, 95% CI: 0.94-2.54), low subjective socioeconomic status (SES) (b = 1.71, 95% CI: 0.91-2.51), and irregular dental visits (b = 1.65, 95% CI: 0.72-2.58) were associated with higher PSS-10 score. These factors were assumed to be clinical meaningful, given that minimal clinically important difference of PSS-10 fell between 2.19 and 2.66 points. The majority of the medical and dental students reported moderate PS. Based on statistical significance and clinical meaningfulness, socio-demographic factors (sex, faculty), subjective SES, and OH behavior (regularity of dental visits) were associated with PS.

Deep carious lesions and other consequences of caries among 18-year-olds at Public Dental Health Service in Northern Norway: A cross-sectional age cohort study.

OBJECTIVES: To document deep carious lesions and other consequences of caries (DCL-CC) in molars of 18-year olds leaving the free-of-charge Public Dental Health Service (PDHS). To explore the association between background factors and DCL-CC. MATERIALS AND METHODS: The final study sample (n=1876) comprised 95% of individuals born in 1993 and registered in the PDHS in Troms County, Northern Norway. The most recent digital bitewing radiographs of each subject were examined for DCL-CC (deep untreated carious lesions, deep restorations, root canal obturations or extractions due to caries). Inter- and intra-observer kappa scores were 0.62 and 0.87, respectively. Information on background factors (gender, clinic location, history of medical problems, bitewing examination interval, DMFT score and planned recalls) were retrieved from dental records. RESULTS: About one-quarter of subjects (488) had at least one molar with DCL-CC. There were 848 molars in total with DCL-CC; the majority were deep restorations (70%), but 4% were deep untreated carious lesions. More than a quarter of DCL-CC were either root canal obturations (14%) or extractions (12%). Multivariable logistic regression analyses showed that a 1-unit increase in DMFT score was associated with deep untreated carious lesions and extractions due to caries. There was no association between urban/rural clinic location, which indicated socio-economic status, and either DMFT score or DCL-CC. CONCLUSIONS: Despite the existence of a free-of-charge dental service, more than one-quarter of the subjects in the present study had at least one molar with DCL-CC.