Does an Association Exist Between the Presence of Lower Third Molar and Mandibular Angle Fractures?: A Meta-Analysis.

PURPOSE: The current data suggest that the presence of lower third molars predisposes the patient to a greater risk of mandibular angle fracture. Thus, the present review sought to determine whether an association exists between the presence of a lower third molar and the occurrence of a mandibular angle fracture in adults and to assess the influence of third molar position according to the Pell and Gregory classification. MATERIALS AND METHODS: The present study was a systematic review and meta-analysis of analytical observational studies. The present review included all reports of the relationship between mandibular angle fractures and lower third molars. No restriction regarding year, language, or publication status was used. The review protocol was registered at the PROSPERO database (registration no. CRD42016047057). Electronic searches unrestricted for publication period and language were performed in the PubMed, Scopus, SciELO, and Latin American and Caribbean Health Sciences databases. Google Scholar and OpenGrey databases were used to search the "gray literature," avoiding selection and publication biases. The entire search was performed by 2 eligibility reviewers. Association and proportion meta-analyses were planned for the studies with sufficient data. The primary predictor variable was the relationship between the presence of a lower third molar and the development of mandibular angle fractures. The secondary outcome variables were the vertical and horizontal positions of the lower third molar, according to the Pell and Gregory classification and their relationship to the susceptibility to developing a mandibular angle fracture. RESULTS: The search strategies resulted in 411 studies, from which 16 were selected for qualitative and quantitative review. The association meta-analysis included all the selected studies and showed that patients with lower third molars are 3.16 times more likely to develop mandibular angle fractures. The proportion meta-analysis included 5 studies and showed that the overall rate of mandibular angle fractures was 51.58% and that positions III and C are more likely to result in fracture, with a rate of 59.84 and 63.67%, respectively. CONCLUSIONS: The results of the present study have shown that the presence of impacted third molars increases by 3.16 times the risk of mandibular angle fractures in adults, with the greatest risk present when third molars are classified as IIIC according to Pell and Gregory. The available evidence is not sufficiently robust to determine whether third molar presence or the level of impaction is the main causative factor for the occurrence of mandibular angle fractures.

Influence of third molars in mandibular fractures. Part 2: mandibular condyle-a meta-analysis.

The aim of this systematic review was to investigate the influence of the presence and position of mandibular third molars in mandibular condyle fractures. An electronic search was conducted in PubMed, Scopus, Web of Science, Cochrane Library, and VHL, through January 2016. The eligibility criteria included observational studies. The search strategy resulted in 704 articles. Following the selection process, 13 studies were included in the systematic review and 11 in the meta-analysis. In terms of the risk of bias analysis, six studies presented ≤6 stars in the Newcastle-Ottawa scale assessment. The presence of a mandibular third molar decreased the probability of condylar fracture (cross-sectional and case-control studies: odds ratio (OR) 0.26, 95% confidence interval (CI) 0.17-0.40, I2=87.8%; case-control studies: OR 0.30, 95% CI 0.16-0.58, I2=91.6%). The third molar positions most favourable to condylar fracture according to the Pell and Gregory classification are class A (OR 1.32, 95% CI 1.09-1.61, I2=0%) and class I (OR 1.37, 95% CI 1.05-1.77, I2=32.8%). Class B (OR 0.69, 95% CI 0.49-0.97, I2=56.0%) and class II (OR 0.71, 95% CI 0.57-0.87, I2=0%) act as protective factors for condylar fracture. The results suggest that the presence of a mandibular third molar decreases the chance of condylar fracture and that the positions of the third molar most favourable for condylar fracture are classes A and I, with classes B and II acting as protective factors.

Influence of third molars in mandibular fractures. Part 1: mandibular angle-a meta-analysis.

The aim of this systematic review was to investigate the influence of the presence and position of mandibular third molars on angle fractures. An electronic search was conducted in the PubMed, Scopus, Web of Science, Cochrane Library, and VHL databases, through January 2016. The eligibility criteria included observational studies. The search strategy resulted in 704 articles. Following the selection process, 35 studies were included in the systematic review and 28 in the meta-analysis. Twenty studies presented a score of ≤6 stars in the Newcastle-Ottawa scale assessment, indicating a risk of bias in the analysis. The presence of a mandibular third molar increases the chance of an angle fracture (case-control and cross-sectional studies: odds ratio (OR) 3.83, 95% confidence interval (CI) 3.02-4.85, I2=83.1%; case-control studies: OR 3.27, 95% CI 2.57-4.16, I2=81.3%). The third molar positions most favourable to angle fracture according to the Pell and Gregory classification are class B (OR 1.44, 95% CI 1.06-1.96, I2=87.2%) and class II (OR 1.67, 95% CI 1.36-2.04, I2=72.4%). Class A (OR 0.60, 95% CI 0.45-0.81, I2=87.1%) and class I (OR 0.51, 95% CI 0.37-0.71, I2=89.4%) act as protective factors for angle fracture. The results suggest that the presence of the third molar increases the chance of angle fracture by 3.27 times and that the most favourable positions of the third molar for angle fracture are classes B and II, whilst classes A and I act as protective factors.

Impact of the lower third molar presence and position on the fragility of mandibular angle and condyle: A Three-dimensional finite element study.

The aim of the present study was to investigate the influences of the presence and position of a lower third molar (M3) on the fragility of mandibular angle and condyle, using finite element analysis. From computed tomographic scans of a human mandible with normally erupted M3, two additional virtual models were generated: a mandibular model with partially impacted M3 and a model without M3. Two cases of impact were considered: a frontal and a lateral blow. The results are based on the chromatic analysis of the distributed von Mises and principal stresses, and calculation of their failure indices. In the frontal blow, the angle region showed the highest stress in the case with partially impacted M3, and the condylar region in the case without M3. Compressive stresses were dominant but caused no failure. Tensile stresses were recorded in the retromolar areas, but caused failure only in the case with partially impacted M3. In the lateral blow, the stress concentrated at the point of impact, in the ipsilateral and contralateral angle and condylar regions. The highest stresses were recorded in the case with partially impacted M3. Tensile stresses caused the failure on the ipsilateral side, whereas compressive stresses on the contralateral side.

Evaluation of dental age and associated developmental anomalies in subjects with impacted mandibular canines.

OBJECTIVES: To assess the null hypothesis that there is no difference in the rate of dental development and the occurrence of selected developmental anomalies related to shape, number, structure, and position of teeth between subjects with impacted mandibular canines and those with normally erupted canines. MATERIALS AND METHODS: Pretreatment records of 42 subjects diagnosed with mandibular canines impaction (impaction group: IG) were compared with those of 84 subjects serving as a control reference sample (control group: CG). Independent t-tests were used to compare mean dental ages between the groups. Intergroup differences in distribution of subjects based on the rate of dental development and occurrence of selected dental anomalies were assessed using χ(2) tests. Odds of late, normal, and early developers and various categories of developmental anomalies between the IG and the CG were evaluated in terms of odds ratios. RESULTS: Mean dental age for the IG was lower than that for the CG in general. Specifically, this was true for girls (P < .05). Differences in the distribution of the subjects based on the rate of dental development and occurrence of positional anomalies also reached statistical significance (P < .05). The IG showed a higher frequency of late developers and positional anomalies compared with controls (odds ratios 3.00 and 2.82, respectively; P < .05). CONCLUSIONS: The null hypothesis was rejected. We identified close association of female subjects in the IG with retarded dental development compared with the female orthodontic patients. Increased frequency of positional developmental anomalies was also remarkable in the IG.

Tooth in the line of angle fractures: the impact in the healing process. A retrospective study of 112 patients.

BACKGROUND: There is no consensus regarding the prophylactic removal of mandibular third molars (TM) in fracture lines to facilitate healing. Recent evidence suggests that poor healing is attributed to the limited use of antimicrobials, delayed care and semi-rigid fixation as a treatment method, favoring retention of TM. STUDY DESIGN: A retrospective cohort study of all patients presenting with mandibular angle fractures at the Hippokration General Hospital of Athens (2006-2011) was designed to examine the association between the presence versus absence of TMs in the line of mandibular fractures and the fracture healing process. Development of complications during the healing process was the outcome of interest. Additional factors considered were patient age, sex, and fracture etiology. MATERIALS AND METHODS: Data were extracted from a retrospective chart review, including information from clinical and radiological examinations. The analytical sample included 112 patients with 121 angle fractures. Bivariate methods including Fisher's exact and chi-square tests were used to test the association between TM presence in the fracture line and healing complications. CONCLUSION: This study found no association between the presence of mandibular TM in the fracture line and postoperative complications and the healing process when combined with light intermaxillary fixation for 15 days.

First case of bimaxillary transmigration of impactedcanines: report of a rare case and review of literature / Primeiro caso de transmigração bimaxilar de caninosimpactados: relato de um caso raro e revisão da literatura

Objective: To present a rare case of bimaxillary transmigration of impacted canines. Discussion: Preeruptivemigration of a tooth across the midline is termed transmigration. Transmigration typically affectsthe mandibular canines, but occurs rarely in maxillary canines as well. Transmigration of mandibular canineacross the midline is rare. An even less common finding is transmigration of maxillary canine acrossthe midline. The least common finding is bimaxillary occurrence of canines transmigration. Conclusion:Migration of both upper and lower canine teeth on the same side across the midline is called bimaxillarytransmigration, which is a very rare phenomenon of oral and maxillofacial complex, often undetected inroutine dental examination, neither clinical, nor periapical radiographic examination.

Objetivo: Apresentar um caso raro de transmigração bimaxilar de caninos impactados. Discussão: A migraçãopré-eruptiva de um dente através da linha média é denominado transmigração. A transmigraçãotipicamente afeta os caninos inferiores, mas pode ocorrer raramente em caninos superiores também. Transmigraçãode canino inferior através da linha média é rara, porém um achado ainda menos comum é a ocorrênciade transmigração bimaxilar de caninos. Conclusão: A migração de caninos superiores e inferiores nomesmo lado e cruzando a linha média é chamada de transmigração bimaxilar, um fenômeno raro de sistema bucal e maxilofacial, frequentemente diagnosticado em exame clínico odontológico de rotina ou exame radiográficoperiapical.

Effect of lower third molars on the incidence of mandibular angle and condylar fractures.

PURPOSE: Numerous previous studies already have proven that mandibles with a third molar are significantly more susceptible to angle fracture by external force. Similarly, other data suggest that the absence of a third molar increases the risk of condylar fracture, while concurrently decreasing the risk of angular fracture. We attempt to characterize the effect of a third molar on the incidence of mandibular angle and condylar fractures. METHODS: This retrospective study reviews data from 385 patients, all of whom were seen in our clinics between February 2006 and November 2009. All data were collected from clinical examination notes and panoramic radiographs, with third-molar state evaluated by the Pell and Gregory classification system. RESULTS: Our results mirror those of previous studies. The incidence of mandibular angle fracture was significantly greater on sides with a third molar, whereas the condylar fracture rate significantly increased in mandibles lacking a third molar or without a fully erupted third molar. The rate of symphysis and mandibular angle fracture was also high in cases of multiple comorbid fractures. CONCLUSIONS: Both the presence and the state of the lower third molar affect the risk of future mandibular angle and condylar fracture.

The value of the dental impaction pain model in drug development.

The modern version of the Dental Impaction Pain Model (DIPM) was developed in the mid-1970s. Since that time, several hundred studies have been conducted by numerous investigators. Today it is arguably the most utilized of all the acute pain models. Its popularity is due to the success rate of the studies, fast subject entry, and cost effectiveness. The surgical procedure is extremely standardized, and the surgery requires either minimal or no use of CNS depressant anesthetics. The methodology is similar to that utilized in other acute pain models; however, the DIPM is much more versatile than most other models. The model can be easily adapted to perform multiple-dose studies, pharmacokinetics/pharmacodynamics (PK/PD) correlations, preemptive interventions, and sleep-pain studies. A few investigators have even developed microdialysis techniques, wherein they insert probes into extraction sockets to collect exudates for measuring biochemical mediators of pain or drug levels at the site of injury. In many instances, an accomplished site can complete a study of several hundred subjects in approximately 3 months. There are studies in the literature that have incorporated up to six treatment arms in one study and clearly separated the drugs from each other. The exquisite assay sensitivity is due to the homogeneity of the study population, the predictable level and appropriate intensity of the postsurgical pain, and the minimizing of variability by using only one or two study centers. The DIPM has been employed to evaluate NSAIDs (both nonselective and selective Cox inhibitors), opioids and combination analgesics, as well as some investigational drugs with unique mechanisms of action. The model is particularly useful for proof-of-concept studies that require dose-ranging and profiling the time-effect curve for efficacy including onset, peak effect, and duration of analgesic activity.

Eruption prediction of mandibular premolars associated with dentigerous cysts.

OBJECTIVE: A tooth with a dentigerous cyst (DC) does not always erupt by marsupialization. The eruption duration and conditions of DC-associated premolars were examined to predict such eruption following marsupialization. STUDY DESIGN: The eruption and conditions including depth, root formation, inclination, and eruption space were examined retrospectively in 21 DC-associated mandibular premolars using dental and panoramic radiograms. RESULTS: Fifteen of 21 premolars erupted half within 3 months and all 15 erupted completely within 10 months after marsupialization, without orthodontic traction. The age of the patients, tooth depth, and inclination were significantly different between the erupted and non-erupted groups, whereas there was no significant difference in the root formation or the eruption space between the 2 groups. CONCLUSIONS: The successful eruption of a DC-associated premolar can be predicted within 3 months after marsupialization. Furthermore, the eruption may be affected by the patient's age, tooth depth, and tooth inclination.

Radiographic study of the positional changes and eruption of impacted third molars in young adults of an Asian Indian population.

PURPOSE: The aim of the study was to assess changes in the angular position and eruption status of third molars in students of an Asian Indian population during a 4-year follow-up period. PATIENTS AND METHODS: The series consisted of 43 students (11 males, 32 females). Standardized panoramic radiographs were taken at baseline (mean age, 19.1 +/- 0.7 years) and at the end of study (mean age 23.1 +/- 0.7 years). Angulation and degree of impaction of third molars were determined by their sagittal relationship to the adjacent second molar and eruption to the occlusal plane. Root formation was also assessed. RESULTS: During the 4-year follow-up period, 11 of 72 of the mandibular teeth (15%) and 17 of 74 of the maxillary teeth (23%) changed their sagittal inclination. Thirty-one of 118 impacted teeth (26%; level B + C) achieved level A eruption more so in the mandible, ie, 15 of 52 (29%), than in the maxilla, ie, 16 of 66 (24%). In the mandible, 9 of 24 impacted vertical teeth (37.5%), 3 of 6 distoangular teeth (50%), and 3 of 22 mesioangular impacted teeth (13.6%) erupted to the occlusal plane. In the maxilla, 9 of 36 impacted vertical teeth (25%) and 7 of 27 distoangular teeth (26%) erupted to the occlusal plane during the follow-up. The number of teeth with complete root formation increased in mandible from 61% to 93% and in maxilla from 62% to 94.5%. CONCLUSIONS: Unpredictable changes in the position and angulation of teeth continued to occur even after the age of 19 years, more so in vertical and distoangular teeth than in mesioangular teeth.

Panoramic findings for predicting eruption of mandibular premolars associated with dentigerous cyst after marsupialization.

PURPOSE: The purpose of this study was to investigate the eruption of mandibular premolar teeth associated with dentigerous cysts. PATIENTS AND METHODS: A total of 60 cyst-associated teeth in the mandibular premolars were examined retrospectively by using normalized panoramic radiographs. The subjects were divided into 2 groups: the erupted group, in which the teeth had erupted spontaneously after marsupialization, and the nonerupted group. Patient age, as well as impacted premolar angulation to the adjacent teeth axes, the cusp depth, space/tooth size, eruption period and cyst size, as measured on initial images, were used as parameters. RESULTS: Using a logistic model of our data, we found that patient age less than 10 years, cusp depth less than 5.1 mm, angulations less than 25 degrees, and space/tooth size greater than 1.0 enhanced the success of eruption. CONCLUSION: Our findings present predictors of successful eruption of impacted mandibular premolars associated with dentigerous cysts after marsupialization.

Management of ameloblastic fibro-odontoma in a 6-year-old girl preserving the associated impacted permanent tooth.

The ameloblastic fibro-odontoma (AFO) is a rare odontogenic tumor that occurs predominantly in children and is generally associated with unerupted teeth. The choice of treatment for this entity is conservative surgery with enucleation and its prognosis is excellent. However, preserving the associated impacted teeth may make complete removal of the lesion difficult and may explain some cases of recurrence. A case of AFO in a 6-year-old girl treated with enucleation and preservation of an impacted lower left first permanent molar is reported. After two years of follow-up, there were no signs of recurrence and complete spontaneous eruption of the preserved tooth was observed. The present report indicates that the degree of involvement of the impacted tooth by AFO is a fundamental aspect to be considered during radiological analysis and surgical assessment. We concluded that preservation of the impacted permanent teeth associated with this tumor should always be considered and carried out with caution, since they are clearly not included in the surgical cavity.

Assessing oral health-related quality of life in general dental practice in Scotland: validation of the OHIP-14.

OBJECTIVES: To validate the Oral Health Impact Profile (OHIP)-14 in a sample of patients attending general dental practice. METHODS: Patients with pathology-free impacted wisdom teeth were recruited from six general dental practices in Tayside, Scotland, and followed for a year to assess the development of problems related to impaction. The OHIP-14 was completed at baseline and at 1-year follow-up, and analysed using three different scoring methods: a summary score, a weighted and standardized score and the total number of problems reported. Instrument reliability was measured by assessing internal consistency and test-retest reliability. Construct validity was assessed using a number of variables. Linear regression was then used to model the relationship between OHIP-14 and all significantly correlated variables. Responsiveness was measured using the standardized response mean (SRM). Adjusted R(2)s and SRMs were calculated for each of the three scoring methods. Estimates for the differences between adjusted R(2)s and the differences between SRMs were obtained with 95% confidence intervals. RESULTS: A total of 278 and 169 patients completed the questionnaire at baseline and follow-up, respectively. Reliability - Cronbach's alpha coefficients ranged from 0.30 to 0.75. Alpha coefficients for all 14 items were 0.88 and 0.87 for baseline and follow-up, respectively. Test-retest coefficients ranged from 0.72 to 0.78. Validity - OHIP-14 scores were significantly correlated with number of teeth, education, main activity, the use of mouthwash, frequency of seeing a dentist, the reason for the last dental appointment, smoking, alcohol intake, pain and symptoms. Adjusted R(2)s ranged from 0.123 to 0.202 and there were no statistically significant differences between those for the three different scoring methods. Responsiveness - The SRMs ranged from 0.37 to 0.56 and there was a statistically significant difference between the summary scores method and the total number of problems method for symptomatic patients. CONCLUSIONS: The OHIP-14 is a valid and reliable measure of oral health-related quality of life in general dental practice and is responsive to third molar clinical change. The summary score method demonstrated performance as good as, or better than, the other methods studied.

Impacted tooth in mandibular fracture line: treatment with closed reduction.

PURPOSE: Most mandibular fractures occur because of blunt trauma. In some cases, the mandible can be weakened by the presence of an unerupted or impacted tooth. The fate of this tooth in the fracture line and its effects on bone healing remain an important outcome event. MATERIALS AND METHODS: In this study, we analyzed the records of 117 patients with a total of 121 fractures having an unerupted tooth remaining in the fracture line who were treated and followed by the Dental Faculty of Ankara University between 1986 and 1996. All were open fractures, and none of the patients had a history of an acute inflammatory episode related to the unerupted tooth before the injury. Intermaxillary fixation was used in all cases. RESULTS: Three of the patients subsequently required open reduction with internal fixation. The unerupted tooth was not extracted in any patient. The fixation was maintained for an average of 45 days and followed up for 3 months. No complications were encountered. CONCLUSION: According to these results, we suggest that asymptomatic impacted teeth in the fracture line of uncomplicated mandible fractures do not cause delayed healing when treated with closed reduction.

Clinical conditions for eruption of maxillary canines and mandibular premolars associated with dentigerous cysts.

The aim of this study was to investigate the eruption of teeth associated with dentigerous cysts in the mandibular premolar and maxillary canine regions in preadolescents. Fifty-eight cyst-associated teeth, including 47 mandibular premolars and 11 maxillary canines, were examined retrospectively by using normalized panoramic radiographs and histological materials. The subjects were divided into 2 groups: the erupted group, in which the teeth had erupted successfully after marsupialization, and the nonerupted group, in which the teeth had undergone orthodontic traction or cystectomy with removal of the cyst-associated tooth. Eighty-one percent of the mandibular premolars and 36% of the maxillary canines in the cysts erupted successfully about 100 days after marsupialization without traction. The eruption of a mandibular premolar was significantly related to a shallow position in the alveolar bone, shallow angulation of the tooth, and young age of the patient but not to cyst size and dental space for the eruption. The eruption of the maxillary canine was significantly related to the small size of the cyst and the patient's age. The cyst walls of the erupted group showed severe inflammatory cellular infiltration. These findings present a treatment guideline for dentigerous cysts associated with mandibular premolars and maxillary canines in preadolescents.