Radiographic Position of Impacted Mandibular Third Molars and Their Association with Pathological Conditions

Permanent lingual nerve injury after dental procedures: a retrospective study of 228 patients

Lingual nerve injury (LNI) is a rare, serious complication and previous studies include limited numbers of cases. The aim of this retrospective study was to report the neurosensory outcomes for a large patient cohort with permanent LNI and correlate the mechanism of injury (surgical vs non-surgical) to neurosensory characteristics. Demographics, procedural parameters, mandibular third molar (M3) position, surgeon type, neurosensory test results, and symptoms were recorded for 228 patients and analysed. The majority were female (67.1%). Overall, 59.6% of LNIs were caused by M3 removal and 36.4% by local anaesthesia. Complete loss occurred more frequently in surgical LNIs (P = 0.013). The presence of pain did not differ significantly, however the burning type of pain was significantly more frequent in non-surgical LNIs (P = 0.008) along with altered gustation (P = 0.025). The most common M3 position related to LNI was distoangular (40.4%), class III (63.2%), level A (58.1%) (Winter/Pell and Gregory classifications). The majority of patients undergoing M3 removal were >24 years. A total of 71.7% showed no sign of recovery and 5.5% reported further impairment in their condition. Overall, nine patients underwent microsurgical repair. This study presents neurosensory characteristics potentially decisive for timely referral of operable LNIs.

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.

Pathologic conditions associated with impacted third molars: A retrospective study of panoramic radiographs in a Southern Brazilian population

Purpose

This study investigated the prevalence of developmental and acquired pathologic conditions associated with impacted third molars (3Ms) in a Southern Brazilian population and evaluated whether demographic and tooth characteristics were correlated with the presence of bone or tooth lesions.

Materials and Methods

Panoramic radiographs were assessed for developmental (bone-related) or acquired (tooth-related) pathoses associated with impacted upper or lower 3Ms. Data on tooth positioning, tooth development, and patient demographics were collected. A trained, calibrated postgraduate student evaluated all images. Binary and multivariate logistic regression models were used to assess associations between outcomes and the demographic and radiographic variables. The threshold for statistical significance was set at 5% (P<0.05).

Results

The sample comprised panoramic radiographs from 2054 patients, predominantly female (59.2%), with a mean age of 27.2 ± 11.5 years. Overall, 4066 impacted 3Ms were evaluated, revealing 471 (11.6%) developmental and 710 (17.5%) acquired pathoses. Among the developmental pathoses, 460 (95.2%) were indicative of dentigerous cysts. Male sex, lower 3M location, vertical or distoangular positioning, and incomplete root formation were associated with an elevated likelihood of developmental pathology. Lower tooth position, complete root formation, and partial eruption were linked to an increased probability of an acquired pathology in the third or second molar.

Conclusion

The prevalence of pathologic conditions associated with impacted 3Ms was low. Male sex, lower 3M placement, horizontal or distoangular positioning, and incomplete root formation were associated with developmental pathoses, while lower tooth position, complete root formation, and partial eruption were related to acquired pathoses.

Does the "Root Removal First" strategy prevent postoperative complications in the surgical removal of impacted mandibular third molars in the Pell and Gregory class C and horizontal position? - a randomized clinical trial

OBJECTIVE

To evaluate the clinical outcomes of the "Root Removal First" strategy in the surgical removal of impacted mandibular third molar (IMTM) in the class C and horizontal position.

MATERIALS AND METHODS

A total of 274 cases were finally included in the statistics. The positions of IMTM in the horizontal position were confirmed by cone-beam computed tomography (CBCT). Cases were randomly divided into two groups: the "Root Removal First" strategy was applied in the new method (NM) group, and the conventional "Crown Removal First" strategy was executed in the traditional method (TM) group. The clinical information and relevant data upon follow-up were recorded.

RESULTS

The duration of the surgical removal and the incidence rates of lower lip paresthesia in the NM group were significantly lower than those in the TM group. The degree of mobility of the adjacent mandibular second molar (M2) in the NM group was significantly lower than that in the TM group at 30 days and 3 months post-operation. The distal and buccal probing depth of the M2, as well as the exposed root length of M2 in the NM group, were significantly lower than those in the TM group 3 months post-operation.

CONCLUSIONS

The "Root Removal First" strategy can reduce the incidence rate of inferior alveolar nerve injury and periodontal complications of the M2 in the surgical removal of IMTM in class C and horizontal position with high efficiency.

TRIAL REGISTRATION

ChiCTR2000040063.

The pattern of mandibular third molar impaction and its relationship with the development of distal caries in adjacent second molars among Emiratis: a retrospective study

Objectives

The purpose of this study was to investigate the pattern of mandibular third molar (MTM) impaction and associated carious lesions in adjacent mandibular second molars (MSMs) in a sample of Emirati individuals.

Methods

This retrospective study assessed 2000 orthopantomograms of Emirati patients who visited the Specialized Fujairah Dental Center between 2015 and 2020. The depth, ramus relation and angulation of the impacted MTMs were assessed according to the Pell and Gregory classification and Winter’s classification. In addition, carious lesions in adjacent MSMs associated with the evaluated parameters were identified.

Results

A total of 461 (23.05%) of the patients had at least one impacted MTM. The mean age of the study population was 26.24 years. Mesioangular, level B, and class II impactions were the most common, at 47.37% (χ² = 382.134; p < 0.001), 45.48% (χ² = 56.889; p < 0.001), and 74.05% (χ² = 513.099; p < 0.001), respectively. There was a higher percentage of level C impaction among females than among males (χ² = 19.178; p < 0.001). A total of 126 impacted teeth (18.36%) had associated carious lesions. These carious lesions were predominantly found in teeth with mesioangular impactions (χ² = 59.430; p < 0.001), level A and B impactions (χ² = 23.301; p < 0.001), and class II and I impactions (χ² = 17.918; p = 0.006).

Conclusions

It is imperative to raise awareness of soft tissue mesioangular-impacted MTMs, as they are the most frequently associated with the development of carious lesions in adjacent MSMs. Approximately one quarter of evaluated Emiratis had at least one impacted MTM, with the most prevalent pattern being class II, level B, and mesioangular impactions. Furthermore, surgical removal is expected to be more challenging for females than for males.

Orthodontic traction of an impacted maxillary third molar through a miniscrew-anchored cantilever spring to substitute the adjacent second molar with severe root resorption

BACKGROUND

An orthodontic traction technique with a miniscrew-anchored cantilever spring was used for the traction of a deeply impacted maxillary third molar to substitute its adjacent second molar with severe root resorption.

CASE DESCRIPTION

A 30-year-old woman sought multidisciplinary treatment planning for a second molar with severe root resorption caused by a deeply impacted third molar. Panoramic radiographs and cone-beam computed tomographic images showed that the third molar was located on the apical and palatal side of the second molar and that the second molar had severe root resorption. The second molar was removed, and the impacted third molar was orthodontically tractioned occlusally with the aid of a miniscrew-anchored cantilever spring. After 12 months of orthodontic treatment, the maxillary left third molar was successfully tractioned occlusally and well aligned with adjacent teeth for the substitution of the second molar. The patient was satisfied with the treatment outcome.

PRACTICAL IMPLICATIONS

A palatal miniscrew-anchored cantilever spring is an effective and viable technique for the orthodontic traction of deeply impacted third molars to substitute second molars with severe root resorption.

Anatomical Positions of Mesially/Horizontally Impacted Mandibular Third Molars are Significant Predictors for Distal Caries in Adjacent Second Molars

Background

Prevalence of distal caries in mandibular second molars (M2Ms) and its relationship with impacted condition of the adjacent mandibular third molars (M3Ms) have been reported in some studies. The results, however, were ambiguous because of including all impaction types and using univariate analysis for statistics.

Aim

This study aimed to determine anatomical features of mesially/horizontally impacted mandibular third molars (M3Ms) that could predict distal caries in the adjacent mandibular second molars (M2Ms) using multivariable analysis.

Materials and Methods

The study sample consisted of 300 digital panoramic radiographs of patients who underwent impacted M3Ms extraction. Two independent researchers collected the following variables from 446 pairs of M2M-M3M: sex, age, status of distal caries in M2Ms, mesial angulation, and Pell–Gregory classification of M3Ms.

Results

The prevalence of distal caries was 50.67%. Multivariable Firth's logistic regression analysis showed that age (β = 0.066, 95% CI = 0.023–0.113), mesial angulation (<30°: β = −1.205, 95% CI = −1.955 to −0.499; >70°: β = −0.730, 95% CI = −1.184 to −0.282), vertical position (level B: β = 2.275; 95% CI = 0.015–7.175; level A: β = 3.008; 95% CI = 0.755–7.905), and horizontal position (level II: β = 1.515; 95% CI = 0.444–2.874; level I: β = 1.423; 95% CI = 0.283–2.825) were significant variables after adjusting for sex in the final model for predicting distal caries (p < 0.05).

Conclusions

In conclusion, anatomical positions of impacted M3Ms, such as mesial angulation and Pell–Gregory classification were significant predictors of distal caries in M2Ms.

Positive Predictive Value of Panoramic Radiography for Assessment of the Relationship of Impacted Mandibular Third Molars with the Mandibular Canal Based on Cone-Beam Computed Tomography: A Cross-Sectional Study

The aim of the present study was to assess the positive predictive value (PPV) of panoramic radiographic signs in the assessment of the relationship between impacted mandibular third molars (IMTMs) and the mandibular canal (MC). This cross-sectional study was conducted by reviewing 102 cone-beam computed tomography (CBCT) and panoramic radiographs of patients with IMTMs and radiographic signs of the contact of the IMTMs with the MC on panoramic radiographs (i.e., root apex darkening and interference with the white line). A positive relationship of the IMTM roots with the MC based on CBCT findings was recorded as the gold standard. The PPV of panoramic radiographic signs was calculated for the detection of the relationship of the IMTM root with the MC. The IMTMs were in contact with the MC on CBCT scans in 90.1% of the cases. The PPV of root apex darkening and the interference with the white line was found to be 89.09% (95% CI: (77.75, 95.88)) and 91.48% (95% CI: (79.62, 97.63)), respectively. The MC had a buccal position in 63.7%, and a lingual position in 35.2%, of the cases. The contact of IMTMs with the MC was more commonly seen in patients with a lingual position (100% of the samples). The IMTM root apex darkening and interference with the white line of the MC on panoramic radiographs had a high PPV for determination of the contact of IMTMs with the MC. Thus, presence of the above-mentioned risk factors indicates the need for subsequent 3D radiographic assessments.