Identifying the Most Accurate Available Space Analysis Method for Predicting Mandibular Third Molar Eruption or Impaction by Means of Panoramic Radiographs

OBJECTIVE: To determine the frequency of mandibular third molar impaction in different vertical skeletal facial types. METHODOLOGY: Data was collected using pre-treatment records including orthodontic files, pre-treatment lateral cephalograms and OPGs of 90 orthodontic patients. Patients from both genders were included. The age group of selected patients was 18-30 years. Vertical skeletal malocclusion was measured using facial angle and mandibular plane angle on cephalogram to group the subjects into Mesiofacial, Brachyfacial and Dolichofacial patients. Third molar eruption status was assessed using OPG. RESULTS: Results showed that erupted third molars were mostly found in brachyfacial patients. Among 32 erupted mandibular third molars, 16 belong to brachyfacial, 11 belonged to mesiofacial and 5 belonged to dolichofacial group. Complete impaction of mandibular third molar was most common among dolichofacial patients. Among 29 completely impacted mandibular third molars, 14 belong to dolichofacial, 9 belonged to mesiofacial and 6 belonged to brachyfacial group. No significant difference was found for partially impacted third molars among the three groups of facial types. There was higher prevalence of mandibular third molar impaction in females as compared to males. CONCLUSION: Frequency of third molar impaction was found to be highest in dolichofacial patients and lowest in brachyfacial patients due to forward direction of mandibular growth contributing to greater resorption of the anterior border of ramus and the additional space required for third molar eruption.

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Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups

The Angle Orthodontist ◽

10.2319/062714-463.1 ◽

2014 ◽

Vol 85 (4) ◽

pp. 577-584 ◽

Cited By ~ 2

Author(s):

Aleksandar Jakovljevic ◽

Emira Lazic ◽

Ivan Soldatovic ◽

Nenad Nedeljkovic ◽

Miroslav Andric

Keyword(s):

Logistic Regression ◽

Age Groups ◽

Third Molar ◽

Width Ratio ◽

Class Iii ◽

Second Molar ◽

Age Related ◽

Mandibular Third Molar ◽

Lateral Cephalograms ◽

Third Molar Eruption

ABSTRACT Objective: To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups. Materials and Methods: In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors. Results: The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P < .001 and P < .015, respectively). The retromolar space was significantly increased in the adult subgroup for all skeletal classes. The lower third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P < .013). Conclusion: The most favorable values of linear and angular predictors of mandibular third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.

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

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17103716 ◽

2020 ◽

Vol 17 (10) ◽

pp. 3716 ◽

Cited By ~ 1

Author(s):

Myrthel Vranckx ◽

Adriaan Van Gerven ◽

Holger Willems ◽

Arne Vandemeulebroucke ◽

André Ferreira Leite ◽

...

Keyword(s):

Neural Network ◽

Artificial Intelligence ◽

Third Molar ◽

Automated Measurement ◽

Third Molars ◽

Panoramic Radiographs ◽

The Third ◽

Clinically Significant ◽

Reference Measurements ◽

Third Molar Eruption

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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An Analysis of Dentigerous Cysts Developed around a Mandibular Third Molar by Panoramic Radiographs

Dentistry Journal ◽

10.3390/dj7010013 ◽

2019 ◽

Vol 7 (1) ◽

pp. 13 ◽

Cited By ~ 4

Author(s):

Masahiko Terauchi ◽

Satoshi Akiya ◽

Junya Kumagai ◽

Yoshio Ohyama ◽

Satoshi Yamaguchi

Keyword(s):

Dentigerous Cyst ◽

Third Molar ◽

Odontogenic Cysts ◽

Third Molars ◽

Class Iii ◽

Panoramic Radiographs ◽

Mandibular Third Molar ◽

Dentigerous Cysts ◽

Panoramic Images ◽

Mandibular Third Molars

Dentigerous cysts are one of the most prevalent types of odontogenic cysts and are associated with the crown of an unerupted tooth, especially of the mandibular third molar. In this study, the characteristics of a dentigerous cyst developed around a mandibular third molar on panoramic radiographs were investigated. The panoramic images of 257 consecutive dentigerous cyst cases associated with a mandibular third molar were analyzed. The mean age of the patients was 45.9 ± 13.3 years. The size of the cyst did not significantly correlate to the age of the patient. The unilocular type (89.1%) and the crown side type (68.5%) were significant. The associated mandibular third molars had a high frequency of class III (64.6%) and position B (48.3%) in Pell and Gregory classification and of horizontal position (36.3%) in angulation. Dentigerous cysts were thought to originate and grow commonly around deeply impacted third molars. The associated third molar with dentigerous cyst tends to have a mesial inclination. Dentigerous cysts do not appear to develop gradually after the crown formation has finished, but arise at various periods randomly.

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Pattern of Impacted Mandibular Third Molar Teeth in Rangpur Region, Bangladesh: A Radiological Evaluation

KYAMC Journal ◽

10.3329/kyamcj.v12i1.53360 ◽

2021 ◽

Vol 12 (1) ◽

pp. 8-13

Author(s):

Md Rubayet Alam Prodhan ◽

Md Shahidul Islam ◽

Rifat Rezwana ◽

Md Moynul Hasan

Keyword(s):

Third Molar ◽

Third Molars ◽

Radiographic Assessment ◽

Impacted Tooth ◽

Panoramic Radiographs ◽

Impacted Mandibular Third Molar ◽

Mandibular Third Molar ◽

Molar Teeth ◽

Impacted Mandibular Third Molars ◽

Mandibular Third Molars

Background: Third molar is the most commonly impacted tooth in the oral cavity and accounts for large of all impactions. The most common complication in the extraction of the third mandibular molars is nerve and vessels damage. Therefore, thorough radiographic assessment is a necessary to avoid these surgical complications. Objective: The purpose of this study was to evaluate the frequency, angulation, depth of the impacted mandibular third molars and its relationship with ramus on radiographs. Materials and Methods: This study comprised 800 orthopantomograms (OPGs) of patients attending different dental clinics and hospitals in Rangpur region, Bangladesh between June 2014 to May 2015. Panoromic Radiographic assessment was carried out to evaluate the pattern of third molar impaction in terms of age, gender, angulation of impaction, level of eruption and available retromolar space using panoramic radiographs and Pell & Gregory classification. Results: A total of 314 radiographic third molar areas were found in this study, out of them 137 belong to male patients and 177 belong to the female patients. The mesio angular types of angulation was most prevalent (46%) whereas distoangular was rare (5%) in our study. In relation to anterior border of the ramus of mandible Level B 52% and Class II 59% were the most common pattern of impaction. The female tends to be dominant as compared to male & the maximum number (35%) of impacted third molars are found in an age group of 38 years and above. Conclusion: Panoramic radiographs can be used as reliable investigation for evaluation of impacted mandibular third molar. KYAMC Journal.2021;12(01): 08-13

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Orthodontic treatment with passive eruption and mesialization of semi-impacted mandibular third molar in an adult with multiple dental losses

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.24.6.036-047.oar ◽

2019 ◽

Vol 24 (6) ◽

pp. 36-47

Author(s):

Armando Yukio Saga ◽

Ariane Ximenes Graciano Parra ◽

Isteicy Cortêz Silva ◽

Cayana Dória ◽

Elisa Souza Camargo

Keyword(s):

Case Report ◽

Adult Patient ◽

Female Patient ◽

Dental Implant ◽

Orthodontic Treatment ◽

Third Molar ◽

Impacted Tooth ◽

Impacted Mandibular Third Molar ◽

Mandibular Third Molar ◽

Third Molar Eruption

ABSTRACT Objective: This article describes the orthodontic treatment performed on an adult patient with multiple dental losses. Case report: A female patient, 20 years and 4 months old, presented with the following conditions: absence of teeth #26, #35, #36 and #46; semi-impacted tooth #48; inclined molars adjacent to an edentulous space; canines and premolars in a Class II relationship; a convex profile; biprotrusion; and forced lip sealing. Results: Space in the region of tooth #26 was closed, as well the space of tooth #46; tooth #48 erupted and followed mesial movement passively; space of the region of tooth #35 was maintained for the placement of a dental implant; uprighting of tooth #37 was obtained. Aesthetic and functional goals of the treatment were achieved. Results remained stable 10 years after the end of the treatment. Conclusion: The modified helical loop could be effectively used in orthodontic mechanics to close edentulous spaces. Passive semi-impacted mandibular third molar eruption and mesialization can occur in adults when proper space is provided.

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