Three-dimensional position of mandibular third molars and its association with distal caries in mandibular second molars: a cone beam computed tomographic study

The influence of arch shape on the incidence of third molar impaction: A cross-sectional study

Introduction

Impaction of third molar is a pathological problem that reduces the chance of normal eruption of tooth. The main reason for impaction is inadequate space in the maxillary and mandibular arch. The aim of this study is to investigate the relationship between arch shape and the prevalence of third molar impaction.

Methods

This cross‑sectional study was performed on patients referring to the Department of Oral and Maxillofacial Surgery between December 2023 and February 2024 to obtain an orthopantomogram (OPG). Convenience sampling was employed, and orthopantomograms were analyzed to determine impaction types. Dental arch shape variables were assessed using Budiman's analysis, with a Chi-square test employed to evaluate any significant association between arch shape and impaction type at a significance level of 0.05.

Results

Among the 185 maxilla and 185 mandibles studied, 154 were male patients, and 216 were female patients, with a mean age of 26.75 years. A statistically significant difference was found in impacted teeth, among females having more impacted molars than males (p-value = 0.002*). However, no significant differences were found in the type of impaction, Gregory classification, or position based on the shape of the mandible on both the right and left sides (p-value > 0.05). Similarly, no significant differences were observed in Gregory's classification based on the shape of the maxilla on both the right and left sides. However, there is a statistically significant difference in the occurrence impaction based on the maxilla's shape (p-value < 0.05).

Conclusion

The study suggests a significant correlation between maxillary arch shape and the occurrence of third molar impaction, with a higher prevalence among females.

The relationship of the position of mandibular third molar impaction with the development of dental and periodontal lesions in adjacent second molars

OBJECTIVE

The aim of this study was to evaluate the effect of different positions of Mandibular third molar impaction teeth on dental and periodontal lesions of mandibular second molars and correlate the lesion severity with patient age.

MATERIALS AND METHODS

This retrospective study assessed 212 CBCT images of patients who visited the department of Oral and Maxillofacial radiology of XX university between 2017 and 2021. Periodontal and dental lesion effects of impacted third molars on mandibular second molars were evaluated. While dental lesions were classified as mild, moderate, and severe, periodontal lesions were classified as mild in cases not exceeding 2/3 of the root, and severe in cases exceeding 2/3 of the root. Pearson's chi-square tests, Mann-Whitney U or Kruskal-Wallis test were used for data analsis. A multivariate logistic regression model was constructed for further analysis.

RESULTS

Periodontal lesions were frequently observed in the second molar adjacent to the third molar (157 teeth, 74.1%), dental lesions were observed in 10%. Among the third molar positions, the mesioangular position was associated with a high (88%) prevalence of periodontal lesions (p<0.001), followed by the horizontal position (71%). The periodontal lesion was more severe in cases 30-39 years old and over 40 years old than in cases under 20 years old and 21-24 years old. Distoangular, horizontal and vertical/inverse positions are less likely to increase the severity of the periodontal lesion than the mesioangular position. (OR = 0.02; p <0.001, OR = 0.28; p =0.008, OR = 0.14; p <0.001,respectively).

CONCLUSIONS

The third molars are often impacted in the mesioangular position, and this position most increases the risk of periodontal infection in the second molars. Accurate diagnosis and evaluation can minimize complications, and CBCT is a reliable imaging technique in which the position of the third molars and their relationship with the 2nd molars can be evaluated.

Mandibular Second Molars and Their Pathologies Related to the Position of the Mandibular Third Molar: A Radiographic Study

Objective

The aim of this study was to determine the prevalence of mandibular third molar malposition and its impact in relation to the lower second molar using panoramic radiography.

Methods and Materials

This was a cross-sectional descriptive study of 353 panoramic images of patients who visited the Dental Clinic of the International University of Rabat. Panoramic images were analyzed in order to determine the number of second molar pathologies associated with the positions of third molars. The following radiographic lesions on the second molar were recorded: caries, root resorption and distal alveolysis. The Chi-square test was used to assess the association between different variables.

Results

Of these 353 radiographies, 169 were males, ie, 48%, and 184 were females, ie, 52%. The age range was from 18 to 63 years. The prevalence of the impacted position of the lower third molar was noted in 60%. Distal caries on the second mandibular molar was present in 47.5% of instances having an impacted third molar. Caries was present in 65.5% of wisdom teeth in a normal position and was also present in 79.6% of the impacted teeth. This difference was statistically significant with p = 0.01. The angulation of the third molar is a factor of caries of the second molar: 58.56% of them were carious. Of all the teeth in association with an angulation, 72.03% showed distal alveolysis in the second molar. In addition, root resorption was found in 20.4% of second molars linked to a wisdom tooth in all angulation occurrences.

Conclusion

It has been noted that among the pathologies seen on the mandibular second molar, distal alveolysis accounts for the majority of cases (58%), followed by caries (47.5%) and root resorption (13.3%). This study illustrated the importance of performing Orthopantomogram X-rays at each new consultation in patients over the age of 18.

The Association Between Skeletal Facial Types and Third Molars Impaction in a Saudi Arabian Subpopulation: A CBCT Study

Purpose

To assess the state of mandibular and maxillary third molars in relation to different facial types in a Saudi population using cone-beam computed tomography (CBCT) records.

Patients and Methods

A retrospective study was performed on CBCTs. Statistical analysis determined the relationship between impacted maxillary and mandibular third molars and different skeletal facial types. The degree of third molar impaction was evaluated.

Results

A total of 198 CBCTs from subjects were evaluated, with a mean age of 34.2 years. Archer II classification was found to be significantly associated with all skeletal profiles. The incidence of mesioangular impactions in lower third molar showed a notable increase in the brachyfacial group, which was statistically significant.

Conclusion

In conclusion, this study demonstrates that different facial types are associated with the angulation of third molar impactions.

Cone-beam computed tomography-based radiographic considerations in impacted lower third molars: Think outside the box

Purpose

This study aimed to evaluate the anatomic circle around the impacted lower third molar to show, document, and correlate essential findings that should be included in the routine radiographic assessment protocol as clinically meaningful factors in overall case evaluation and treatment planning.

Materials and Methods

Cone-beam computed tomographic images of impacted lower third molars were selected according to specific inclusion criteria. Impacted teeth were classified according to their position before assessment. The adjacent second molars were assessed for distal caries, distal bone loss, and root resorption. The fourth finding was the presence of a retromolar canal distal to the impaction. Communication with the dentist responsible for each case was done to determine whether these findings were detected or undetected by them before communication.

Results

Statistically significant correlations were found between impaction position, distal bone loss, and detected distal caries associated with the adjacent second molar. The greatest percentage of undetected findings was found in the evaluation of distal bone status, followed by missed detection of the retromolar canal.

Conclusion

The radiographic assessment protocol for impacted third molars should consider a step-by-step evaluation for second molars, and clinicians should be aware of the high prevalence of second molar affection in horizontal and mesioangular impactions. They also should search for the retromolar canal due to its associated clinical considerations.

Can the Position of the Impacted Third Molars Be an Early Risk Indicator of Pathological Conditions? A Retrospective Cone-Beam Computed Tomography Study

Objectives

The aim of this retrospective study was to evaluate the prevalence of pathologies associated with impacted third molars in relation to tooth position on cone-beam computed tomography images.

Material and Methods

In 348 cone-beam computed tomography images, the position of 640 impacted third molars (mesiodistal angulation, buccolingual inclination, impaction depth, and contact point localization) and the presence of pathologies (distal caries, external root resorption, marginal bone loss, and pathological follicular space) were evaluated. The data were analysed statistically with a significance level set at P < 0.05.

Results

Distal caries was mostly detected in relation to Class A (20.4%) and contact point at (12.5%) and above (10.5%) the cementoenamel junction (CEJ) (P = 0.000; P < 0.05). External root resorption and marginal bone loss were more common in mesioangular angulation (52.3% and 80.1%, respectively), Class C (53% and 73.8%, respectively), and contact point below the CEJ (53.2% and 73.3%, respectively) (P = 0.000; P < 0.05). Lingual inclination was identified as a new risk factor for associated pathologies (P < 0.05). Pathological follicular space was significantly more likely to occur in those with inverted angulation (100%) and absence of contact (31.5%) (P = 0.000 and P = 0.010, respectively; P < 0.05).

Conclusions

Pathologies arising in second molars in relation to impacted third molars are significantly associated with the three-dimensional position of impacted third molars, and watchful monitoring or prophylactic removal of impacted third molars should be considered, taking into account the relevant risk parameters for the related pathologies.

Parameters associated with radiographic distal surface caries in the mandibular second molar adjacent to an impacted third molar

BACKGROUND

To determine the risk factors for the development of radiographic distal surface caries (rDSC) in patients who attend routine dental check-ups during an era of National Institute for Health Care Excellence third molar surgery guidelines.

METHODS

Radiographs taken during routine dental examinations involving 1012 patients from Manchester, UK were accessed. Clinical parameters, oral health, patient demographics, and socioeconomic factors were assessed. Risk factors were identified by multivariate logistic regression analysis.

RESULTS

The detected rate of rDSC was 63.9% and rDSC was distributed homogenously across all five socioeconomic groups (p = 0.425). Risk factors associated with rDSC (p < 0.001) were identified as partially erupted mesio-angularly impacted mandibular third molars, third molars with compromised molar to molar contact points, loss of lamina dura of ≥ 2 mm, male gender, increasing age, and a higher modified Decayed Missing Filled Tooth score.

CONCLUSION

rDSC was significantly associated with the angulation of third molars, the compromised contact position of the adjacent third molar, the periodontal status of the distal aspect of the second molar and the cumulative history of oral health in a population governed by specific third molar guidelines. An active approach to third molar surgical management could reduce rDSC and serve this population, irrespective of patients' socioeconomic or deprivation status.

Computer-aided three-dimensional assessment of periodontal healing distal to the mandibular second molar after coronectomy of the mandibular third molar: a prospective study

Background

The periodontal healing distal to the mandibular second molar (M2M) after coronectomy of the M3M has shown controversial results. We aimed to combine a digital method with cone-beam computed tomography (CBCT) and estimate periodontal healing of M2M after M3M coronectomy. An accurate and stable indicator in three dimensions was also explored tentatively.

Methods

Patients with a M3M in contact with the inferior alveolar canal were included. CBCT was applied immediately after coronectomy (baseline) and 6-months later. Data were investigated with digital software for registration. Previously reported and coronectomy-related factors were included for univariate and multivariate analyses.

Results

A total of 181 patients (213 M3Ms) completed 6-month follow-up. Significant reduction in the distal intra-bony defect (DBD) depth of the M2M was shown (1.28 ± 1.24 mm, P < 0.001). DBD depth of the M2M at baseline was the most influential factor (r = 0.59), followed by preoperative M3M condition, age, rotation and migration of the root complex. Remaining enamel (OR = 6.93) and small retromolar space (0.67) contributed to re-contact of the root complex and M2M. Bone volume regenerated in the distal 2 mm was associated significantly with DBD-depth reduction (r = 0.74, P < 0.001).

Conclusions

Bone volume regenerated in the distal 2 mm of the M2M denoted stability of distal periodontal healing of the M2M. DBD depth at baseline was the most influential factor for healing of a DBD of the M2M after M3M coronectomy. The remaining enamel and a small retromolar space could contribute to re-contact of the root complex and the M2M.

Trial registration

China Clinical Trial Center, ChiCTR1800014862. Registered 10 February 2018,