Artificial Intelligence (AI)-Driven Molar Angulation Measurements to Predict Third Molar Eruption on Panoramic Radiographs

The purpose of the presented Artificial Intelligence (AI)-tool was to automatically segment the mandibular molars on panoramic radiographs and extract the molar orientations in order to predict the third molars’ eruption potential. In total, 838 panoramic radiographs were used for training (n = 588) and validation (n = 250) of the network. A fully convolutional neural network with ResNet-101 backbone jointly predicted the molar segmentation maps and an estimate of the orientation lines, which was then iteratively refined by regression on the mesial and distal sides of the segmentation contours. Accuracy was quantified as the fraction of correct angulations (with predefined error intervals) compared to human reference measurements. Performance differences between the network and reference measurements were visually assessed using Bland−Altman plots. The quantitative analysis for automatic molar segmentation resulted in mean IoUs approximating 90%. Mean Hausdorff distances were lowest for first and second molars. The network angulation measurements reached accuracies of 79.7% [−2.5°; 2.5°] and 98.1% [−5°; 5°], combined with a clinically significant reduction in user-time of >53%. In conclusion, this study validated a new and unique AI-driven tool for fast, accurate, and consistent automated measurement of molar angulations on panoramic radiographs. Complementing the dental practitioner with accurate AI-tools will facilitate and optimize dental care and synergistically lead to ever-increasing diagnostic accuracies.

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Evaluation of Panoramic Radiographs in Relation to the Mandibular Third Molar and to Incidental Findings in an Adult Population

European Journal of Dentistry ◽

10.1055/s-0040-1721294 ◽

2020 ◽

Author(s):

Josefine Cederhag ◽

Nina Lundegren ◽

Per Alstergren ◽

Xie-Qi Shi ◽

Kristina Hellén-Halme

Keyword(s):

Incidental Findings ◽

Adult Population ◽

Inferior Alveolar Nerve ◽

Third Molar ◽

Patient Positioning ◽

Vertical Position ◽

Surgical Removal ◽

Third Molars ◽

Panoramic Radiographs ◽

The Third

Abstract Objectives The aim was to evaluate the characteristics of the mandibular third molars, especially in relation to the inferior alveolar nerve. Further aims were to investigate incidental findings in panoramic radiographs in an adult population, and to investigate image quality related to patient positioning. Materials and Methods From a previous study with 451 randomly selected adult participants who lived in Sweden, 442 panoramic radiographs from four dental public health clinics were used. The third molars’ characteristics and relation to inferior alveolar nerve were evaluated. Incidental findings and patient positioning were recorded. Statistical Analysis Frequency analysis was used to investigate the occurrence of all findings and their possible interconnections. Whether the patients’ age or gender had an impact or not was also analyzed. Results The third molars were erupted in vertical position among 73% regardless of age. When retained or semi-retained, they were most commonly in mesioangular positions. The inferior alveolar nerve was located inferior to the roots in 52%, whereas an overlapped position was most common if the third molar was retained (90%), semi-retained (83%) or the age was less than 30 years (66%). Common incidental findings were apical radiolucencies, idiopathic osteosclerosis, and tooth fragments. Suboptimal patient positioning was found in one-third of the radiographs. Conclusions Panoramic radiography is a useful method to evaluate third molar prior to surgical removal and may be the only image required. Most incidental findings on panoramic radiographs does not seem to require any further odontological management.

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Third Molar Eruption Mechanisms and Patterns

Dentistry 3000 ◽

10.5195/d3000.2016.49 ◽

2016 ◽

Vol 4 (1) ◽

pp. 11-16

Author(s):

Winnie Zhang

Keyword(s):

Molecular Mechanisms ◽

Third Molar ◽

Radiographic Examination ◽

Third Molars ◽

The Third ◽

Occlusal Surfaces ◽

Surgical Extraction ◽

Incipient Caries ◽

The Moment ◽

Third Molar Eruption

Third molars are highly variable in their presence and form. This report focuses on a horizontally impacted third molar and analyzes the potential etiology of this situation. Upon a clinical and radiographic examination, it was noted that the patient had four third molars present. The patient’s third molars began erupting around the age of 19. Currently, they are asymptomatic with incipient caries on the occlusal surfaces. While three of the third molars erupted in a normal orientation, one of the third molars (mandibular left) erupted in an orientation that would be classified as horizontal and/or mesio-angular. No treatment has been undertaken at the moment, however surgical extraction can be recommended with the prognosis being very good. For the clinician that has to treat dental complications that arise from abnormal tooth eruption, as seen in numerous genetic and acquired disorders, knowledge about the basic molecular mechanisms involved may become extremely important.

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Prevalence of third molar impaction in patient with mandibular anterior teeth crowding

Padjadjaran Journal of Dentistry ◽

10.24198/pjd.vol28no3.13673 ◽

2016 ◽

Vol 28 (3) ◽

Author(s):

Tan Chun Wei ◽

Eky Setiawan Soeria Soemantri ◽

Iwa Rahmat Sunaryo

Keyword(s):

Third Molar ◽

Horizontal Position ◽

Third Molars ◽

Probability Sampling ◽

Panoramic Radiographs ◽

Descriptive Research ◽

The Third ◽

Anterior Teeth ◽

Controversial Topic ◽

Sample Range

Introduction: Third molar impaction has been a controversial topic among clinician when it comes to mandibular anterior teeth crowding. The aim is to know the prevalence of third molar impaction in patient with mandibular anterior teeth crowding in Orthodontic Department, RSGM UNPAD, Indonesia. Methods: This was a descriptive research, with non-probability sampling obtained from a population with full arch 32 teeth. Totaling 54 samples from year 2011 to 2014 were obtained. The age of sample range from 15 to 25 years old. Also all panoramic radiographs taken from the year 2011 to 2014 were examined using a computer. The position of third molars were determined by Winter’s classification using angle formed between the intersected longitudinal axes of the second and third molars and anterior teeth status by using Little’s irregularities index. Results: This study obtained data that as much as 68.52% mesioangular third molar, 19.44% distoangular, 4.63% horizontal, 1.85% buccolingual and 0% others. In mesioangular impaction condition there was crowding 83.78%, in distoangular condition there was 100% crowding, in horizontal position crowding found 100%, while at buccolingual crowding found 100%.Conclusion: In all positions the third molar impaction was accompanied by crowding of the mandible anterior teeth, with the largest percentage of impaction was the mesioangular position

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Possibilty of the lower third molar eruption: Radiographic analysis

Vojnosanitetski pregled ◽

10.2298/vsp0602159n ◽

2006 ◽

Vol 63 (2) ◽

pp. 159-162

Author(s):

Nenad Nedeljkovic ◽

Zorana Stamenkovic ◽

Zoran Tatic ◽

Alek Racic

Keyword(s):

Third Molar ◽

Occlusal Plane ◽

Third Molars ◽

The Third ◽

Crown Width ◽

Significant Difference ◽

Mutual Relations ◽

The Right ◽

B Lines ◽

Third Molar Eruption

Backgraund/Aim. To assess the possibility of the eruption of the lower third molar on the basis of the measured parameters: retromolar space, mesiodistal crown width of a molar and the third molar angulation. Methods. The investigation included 104 patients both sexes (43 boys, and 61 girls), 16 to 25 years old (meanage, 18 years). It was performed using the orthopanthomographic radiographs analysis of those patients. Each radiograph was covered by tracing paper, and the contoures of the followiny anatomic details were drawn: a) the crown and root contours of third molars, upper and lower central incisors, distal molars in occlusion, anterior edge of ramus mandible, b) lines: 1. the occlusal plane, 2. the line of retromolar space, 3. the mesiodistal crown width of third molar, 4. the axial shaft of the third molar and the distal angle between occlusal plane and the axial shaft of the third molar. The values were measured with an orthodontic caliper: the diameter of retromolar space, diameter of mesiodistal width, the value of distal angle between occlusal plane and axial shaft of molar. Results. A favourable angulation of the lower third molar (more than 60?) was found in, boys (left 27.90%, right 32.55%), girls (left 39.34%, right 37.77%). A favourable relationship between the diameters of mesiodistal width of the third molar and retromolar space was found in, boys, (left 13.59%, right 16.27%), girls, (left 8.19%, right 14.75%). A favorable relationship between the diameters of mesiodistal width of the third molar and the retromolar space and the angulation was found in boys, (left 9.30%, right 11.62%), girls, (left 6.56%, right 9.83%). Conclusion. There was not any statistically significant difference found between the relation of the retromolar value, third molar mesiodistal diameter, or of the third molar angulation to the left and the right side nor of their mutual relations in comparing boys and girls. A favorable prognosis was found in 9.33% of the patients.

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Age estimation from developing third molars

Medico-Legal Journal ◽

10.1177/00258172211052930 ◽

2021 ◽

pp. 002581722110529

Author(s):

Yvonne Padmini Wilson ◽

Phrabhakaran Nambiar ◽

Hashim Yaacob ◽

Muhammad Khan Asif

Keyword(s):

Root Development ◽

Age Estimation ◽

Third Molar ◽

Growth Patterns ◽

Third Molars ◽

Panoramic Radiographs ◽

The Third ◽

The Subject ◽

Congenitally Missing ◽

Demirjian’S Method

We investigated the development of third molars among Malaysians (including variations between jaws and genders) using Demirjian’s method. Dental panoramic radiographs of 1224 subjects aged 8 to 24 years were examined, and the molars were assigned Demirjian et al.’s development grades (A–H). Results indicated that 18.8% had congenitally missing or extracted third molars. Development of molars begins earlier in females (also in the mandible), but by age 9, male children's molar development speeds up with more advanced grades in their middle teens than females. Grade C indicates the subject is a juvenile, while initiation of root development (Grade E), was observed from 13 years on. Grade H can occur in a child aged 18 years who technically is still a juvenile. We compared the development and growth patterns of the third molar from both the maxilla and the mandible.

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Dental caries on distal surface of mandibular second molars

Brazilian Dental Science ◽

10.14295/bds.2015.v18i1.1063 ◽

2015 ◽

Vol 18 (1) ◽

pp. 51 ◽

Cited By ~ 5

Author(s):

Hudson Oliveira Silva ◽

Antonione Santos Bezerra Pinto ◽

Moara E Silva Conceição Pinto ◽

Marconi Raphael de Siqueira Rego ◽

Jamyra Ferreira Gois ◽

...

Keyword(s):

Third Molar ◽

Dental Radiology ◽

Third Molars ◽

Inclusion Criteria ◽

Panoramic Radiographs ◽

Second Molar ◽

The Third ◽

Mandibular Third Molar ◽

Distal Surface ◽

Sliding Scale

Objective: The aim of the study was to evaluate the frequency of distal caries in the second molar influenced by the angulation of the third molar adjacent on panoramic radiographs in a clinical dental radiology. Material and Methods: A descriptive and quantitative study that examined 750 panoramic radiographs, of this total, 120 were in accordance with the inclusion criteria of the study was conducted. Results: 157 seconds and third molars analyzed the prevalence of caries in the distal of the second molar was 25.5%. The most prevalent angle position of the third molar was 57.3% with the vertical, but the position with the highest percentage of decayed molar second distal mesioangular was 50% of the cases. The elements listed, males obtained 40% of second molar distal caries versus 17% for females. People aged 35 or older had the highest incidence with 50% distal caries while other bands obtained 16.21% in the group 18-24 years, and 23.52% in 25-34 years. Conclusion: It was possible to establish a sliding scale on the indication for prophylactic removal of mandibular third molar according to the angulation of Winter: horizontal, mesioangular, vertical and distoangular. One can also see a greater relevance to the indication of prophylactic removal of male individuals aged over 35 years.

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Prevalence of impacted mandibular third molars among patients attending the dentomaxillofacial radiology clinic

Padjadjaran Journal of Dentistry ◽

10.24198/pjd.vol25no1.26784 ◽

2013 ◽

Vol 25 (1) ◽

Author(s):

Sanjit Singh Munjit Singh ◽

Suhardjo Sitam ◽

Belly Sam

Keyword(s):

Third Molar ◽

Dental Arch ◽

Third Molars ◽

Panoramic Radiographs ◽

Descriptive Research ◽

The Third ◽

Mandibular Third Molar ◽

Impacted Mandibular Third Molars ◽

Mandibular Third Molars

Introduction: The third molar is undoubtedly the most variable tooth in the human dentition, and also the most common tooth to become impacted due to it being the last tooth to erupt into the dental arch The aim of research is to obtain the prevalence of the mandibular third molar (M3) impaction among the patients attending the Radiology Clinic. Methods: The type of research conducted was a descriptive research. The sampling was purposive, drawn from a population of 1451 digital panoramic radiographs taken from January – December in the year 2010, of which 392 samples were included in the survey, with patient ages ranging between 18 – 59 years at time of exposure. The position of the M3’s was assessed using the Pell and Gregory and, Winter’s impaction classification. Results: The prevalence of impacted mandibular M3’s in this study is 76.8% overall. Of the impacted mandibular M3’s present, 76.1% were bilateral impactions and of these bilateral impactions 50.7% are similar in impaction classification. Of the mandibular M3’s examined, 40.1% are in a vertical angulation, 33.3% mesioangular, 23.5% horizontal and 3.1% distoangular. The three most common types of impaction according to the Pell and Gregory classification are IIB at 38.5%, IA at 36.8% and IIA at 18.8%. Conclusion: Prevalence of mandibular third molar of the patients attending the Radiology Clinic is 76.8%.

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Size of the lower third molar space in relation to age in Serbian population

Vojnosanitetski pregled ◽

10.2298/vsp110509017z ◽

2013 ◽

Vol 70 (10) ◽

pp. 923-928 ◽

Cited By ~ 2

Author(s):

Ksenija Zelic ◽

Nenad Nedeljkovic

Keyword(s):

Age Groups ◽

Third Molar ◽

Adult Patients ◽

Width Ratio ◽

Third Molars ◽

Gonial Angle ◽

Angle Size ◽

The Third ◽

Crown Width ◽

Third Molar Eruption

Background/Aim. It is considered that the shortage of space is the major cause of the third molar impaction. The aim of this study was to establish the frequency of insufficient lower third molar eruption space in Serbian population, to question the differences in this frequency in the subjects of different age, to determine the influence of the lower third molar space (retromolar space) size on third molar eruption, and to investigate a possible correlation between the size of gonial angle and the space/third molar width ratio. Methods. Digital orthopantomograms were taken from 93 patients divided into two groups: early adult (16-18 years of age) and adult (18-26) patients. Retromolar space, mesiodistal third molar crown width, gonial angle and eruption levels were measured. Results. The space/third molar width in early adult subjects was smaller (p < 0.0001) and insufficient space was significantly more frequent (p = 0.0003) than in adult patients. Considerably more third molars erupted in case of enough space in both age groups (p < 0.0001). There was no difference between the means of gonial angle size in relations to the available space. Conclusions. The retromolar space/third molar width ratio is more favorable in adult subjects. Gonial angle is not in correlation with the retromolar space/third molar width ratio.

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Panoramic Radiographic Analysis of Signs of Proximity to the Third Molar Roots of the Mandibular Canal in Yemen

Journal of Medical Clinical Case Reports ◽

10.47485/2767-5416.1017 ◽

2020 ◽

Keyword(s):

Third Molar ◽

Mandibular Canal ◽

Cross Sectional Study ◽

Third Molars ◽

Cross Sectional ◽

Panoramic Radiographs ◽

Second Molar ◽

Female Patients ◽

The Third ◽

Dental Clinics

Objectives: The objectives of this study were to assess the relationship between the third molar and the mandibular canal, to identify the radiographic markers most prevalent in predicting connectivity between these structures, and to associate these signs and proximity with the position of the third molar according to Bell, Gregory’s and Winter’s classifications. Subjects and methods: A retrospective cross-sectional study was conducted in the city of Sana’a on a sample of Yemeni patients in Ammar Dental Clinics who underwent panoramic radiography in the year 2019 until September 2020. The study consisted of panoramic radiographs of 597 patients with third molars with a total of 1017 third molars; the number of males was 216 (36.2%) and 381 females (63.8%). The panoramic radiographs were evaluated for proximity signs. Inclusion criteria were patients of both sexes who had at least a fully formed third molar of the mandible that was adjacent to the second molar. The radiographs were excluded if evidence of cystic, neoplastic, or extensive caries processes was detected. Seven radiological signs were used to determine if there was contact between the third molar and the mandibular canal. Results: A proximity to the mandibular canal was verified for 620 (61%) of 1017 third molars. The most frequent radiographic signs of proximity were darkened roots (315 teeth [31%]) and discontinuity of the mandibular canal (267 teeth [26.3%]). Third molar/mandibular canal proximity was found significantly more frequently in female patients and in patients aged 24 years and younger (P < 0.001). The tooth positions most frequently associated with proximity between the third molar and the mandibular canal were position C (highest point of the third molar located at or below the cervical margin of the second molar) and the mesioangular position (long axis of the third molar angled mesially toward the second molar). Conclusions: The frequency of third molar/ mandibular canal proximity was greater in female patients and patients aged 24 years or younger. The most frequently observed signs of proximity were darkening of the roots and discontinuity of the mandibular canal. The tooth positions most frequently associated with proximity of the third molar to the mandibular canal were position C and the mesioangular position.

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Effect of Genetic and Environmental Factors on the Impaction of Lower Third Molars

Applied Sciences ◽

10.3390/app11041824 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1824

Author(s):

Giedrė Trakinienė ◽

Dalia Smailienė ◽

Kristina Lopatienė ◽

Tomas Trakinis ◽

Antanas Šidlauskas

Keyword(s):

Environmental Factors ◽

Environmental Effect ◽

Third Molar ◽

Considerable Proportion ◽

Third Molars ◽

Common Environment ◽

The Third ◽

The Common ◽

Genetic And Environmental Factors ◽

Third Molar Eruption

The aim of this retrospective study was to evaluate the impact of genetic and environmental factors on the impaction of lower third molars using a classical twin study by evaluation of the third molar eruption space and M3 angulation. The study group consisted of 212 twins: 80 dizygotic and 132 monozygotic twins with digital panoramic radiograms and lateral cephalograms. The zygosity of twins was determined using 15 highly polymorphic DNA regions from the venous blood of twins. The results showed that differences between siblings in the dizygotic and monozygotic twin pairs were not statistically significant. The most fitting model for the angulations of lower third molars was AE (additive genetic and specific environmental effect), where the additive genetic factors had up to 88% influence and the specific environment up to 27%. Therefore, the ACE( additive genetic, common and specific environmental effect), model showed higher significance for the lower third molar eruption level where additive genetic estimates reached 71%, a specific environment contributed up to 15% and the common environment reached 32%. The conclusion was that a considerable proportion of the third molar impaction could be attributed to additive genetic effects and the common environment, whereas the specific environment had a lower, but significant impact.

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