The ability of orthodontists and maxillofacial surgeons in predicting spontaneous eruption of mandibular third molar using panoramic serial radiographs

Assessing position changes of impacted third molars in treatment of class II malocclusion with premolars extraction

INTRODUCTION

Third molars (M3) remaining impacted in Class II malocclusion characterised with sagittal mandibular deficiency is a high probability. The null hypothesis of this study is that mesioangular M3s changes position through the eruption way in Class II malocclusion treatment requiring moderate anchorage with four first premolars extraction. The aim of this study is to reconsider the decision to surgically extract impacted third molars in four premolars extraction treatment of Class II malocclusion.

MATERIAL AND METHODS

The materials consisted of the pre-treatment and post-treatment lateral cephalograms and orthopantomographs of 30 individuals with skeletal and dental Class II malocclusion with a mean chronological age of 13.48 years, who were treated by the same clinician (H.G.) with four first premolar extractions via the straight wire technique at the Ankara University Faculty of Dentistry Department of Orthodontics, Ankara, Turkey. The sagittal position of the upper and lower incisors and molars, M3 position and M3 space were evaluated with the paired-t test; the relationship between the sagittal position of the upper and lower incisors and molars and the change in M3 position were evaluated with correlation analysis.  Results: The study found the retroclination and mesial movement of the upper incisors and molars, and an increase in the M3 space by the fixed orthodontic treatment. An insignificant steepening of both the upper right M3 position and the lower right M3 position was found. A statistically significant increase in the lower right and left side M3 spaces was found. Positive correlations between lower right M3 angulation and the sagittal position of the lower incisors and first molars were found.

CONCLUSION

Improvement in the mesioangulation of the M3s and an increase in the M3 space were achieved in this study. Based on the findings, it is useful to review the decision for prophylactic surgical extraction of the M3s before orthodontic treatment in such cases, taking into account the risks of postoperative complications.

Oral maxillofacial surgeons and Orthodontists' perceptions about anterior inferior crowding and indications of mandibular third molar extraction

BACKGROUND

There are still many doubts about anterior inferior crowding and indications of mandibular third molar extraction, although it is very studied subject in the literature. The aim of this study was to evaluate the perceptions of oral maxillofacial surgeons (OMFSs) and orthodontists about anterior inferior crowding and indications of mandibular third molar extraction.

MATERIAL AND METHODS

A web-based survey was developed and sent to professionals in order to collect their opinion about the fact that third lower molars cause crowding and questions about the indication of third molars for orthodontic treatment. Descriptive analysis was performed and Chi-square or G tests were applied with a 95% confidence interval.

RESULTS

The study included a total of 218 participants, of whom 115 were OMFSs and 103 were orthodontists. The results showed that 56.5% of OMFSs and 35.0% of orthodontists believe that the lower third molars cause anterior inferior crowding (p<0.001). A total of 91.3% of OMFSs and 70.9% of orthodontists indicate the extraction of lower third molars to aid orthodontic treatment (p<0.001).

CONCLUSIONS

It can be concluded that in being an oral maxillofacial surgeon, a higher odds ratio is observed to consider that lower third molars cause dental crowding compared to those who are orthodontist. The indication of exodontia of lower third molars for orthodontic treatment was more frequent among OMFSs when compared to orthodontists.

Factors associated with indication of prophylactic extraction of the lower third molar in orthodontic practice

Background

To date, there is no consensus on the factors that influence on indication for prophylactic extraction of the third molar, however it is a common indication in orthodontics. Aim: To determine the factors associated with indication of prophylactic extraction of the lower third molar in orthodontic practice.

Material and Methods

This cross-sectional analytical study used an online survey to obtain responses from 100 professionals with clinical practice in orthodontics. The Survey Monkey software was used to enter a valid and reliable questionnaire of 11 questions to obtain demographic and clinical information of the professional, as well as some patient conditions that could be considered in a possible indication for prophylactic extraction. The questionnaire was sent through social networks and instant messaging applications. Chi Square test was used to evaluate associated factors and binomial logistic regression to identify risk or protective factors.

Results

Factors significantly associated with indication of prophylactic extraction of the lower third molar were experience in orthodontics (p-value = 0.060; OR=0.325), characteristics of impaction (p-value = 0.012; OR=3.689), prevention of pericoronitis (p-value = 0.014; OR=3.769) and help stability of treatment results (p-value = 0.002; OR=6.074).

Conclusions

The risk factors to indication for prophylactic extraction of the lower third molar were impaction of the third molar, prevention of pericoronitis and helping the stability of the results after treatment. Furthermore, experience in orthodontics was identified as a protective factor for this indication. Key words:Orthodontics, risk factors, third molar, tooth extraction.

Improvement of the Impacted Level of Lower Third Molars After Orthodontic Treatment

OBJECTIVES

The early or delayed surgical removal of an asymptomatic lower third molar (M3) in orthodontic patients remains controversial. This study aimed to determine the changes in the impacted level of M3 such as angulation, vertical position, and eruption space, after orthodontic treatment in 3 groups, namely non-extraction (NE), first premolar (P1) extraction, and second premolar (P2) extraction.

METHODS

Relevant angles and distances related to 334 M3s from 180 orthodontic patients were assessed pre- and posttreatment. Angle between lower second molar (M2) and M3 (M3-M2) was used for evaluating M3 angulation. For M3 vertical position, distances from occlusal plane to the highest cuspid (Cus-OP) and fissure (Fis-OP) of M3 were used. Distances from the distal surface of M2 to anterior border (J-DM2) and centre (Xi-DM2) of the ramus were used for assessing M3 eruption space. Pre- and posttreatment values of the angle and distance in each group were compared using a paired-sample t test. Measurements of the 3 groups were compared using analysis of variance. Hence, multiple linear regression (MLR) analysis was used to determine significant factors that impacted changes in M3s' related measurements. Independent factors used for MLR analysis included sex, treatment starting age, pretreatment respective angle/distance, and premolar extraction (NE/P1/P2).

RESULTS

M3 angulation, vertical position, and eruption space at posttreatment were significantly different from those at pretreatment in all 3 groups. MLR analysis showed that P2 extraction significantly improved M3 vertical position (P < .05) and eruption space (P < .001). P1 extraction significantly decreased Cus-OP (P = .014) and eruption space (P < .001). Treatment starting age was significant factor that affected Cus-OP (P = .001) and M3 eruption space (P < .001).

CONCLUSIONS

After orthodontic treatment, M3 angulation, vertical position, and eruption space changed in favour of the impacted level. These changes in the 3 groups were clearer in order: NE, P1, and P2, respectively.

Eruption Pattern of Third Molars in Orthodontic Patients Treated with First Permanent Molar Extraction: A Longitudinal Retrospective Evaluation

The aim of this study was to evaluate angular and positional changes in the second (M2) and third molars (M3) of orthodontically treated patients undergoing a first molar (M1) extraction. A retrospective longitudinal study with a sample of 152 pre- and post-treatment panoramic radiographs was conducted. Thirty-nine patients (51.3%) were orthodontically treated with M1 extraction and thirty-seven (48.7%) were treated without extraction. Angulations of M2 and M3 relative to the infraorbital (IOP) and the palatal planes (PP) were measured and compared between the groups before orthodontic treatment (T1) and after the completion of orthodontic space closure (T2). The prognosis of M3 eruptions was evaluated by assessing their horizontal and vertical position (inclination) using different classification systems. The angular (p < 0.001) and inclination improvement (p < 0.01) of the maxillary M3 was significant for the M1 extraction group. The mandibular M3 inclination significantly improved (p < 0.01), whereas the groups' angulation and vertical position were not significantly different. These findings suggest that extraction therapy has a favorable effect on the maxillary M2 and M3 angulation, but not on the mandibular. M1 extraction showed a signi- ficant effect on the horizontal position of M3 and thus may improve the eruption space and prognosis.

Midfacial development and the wisdom of teeth: A case series

The alignment of third molars has largely been overlooked by orthodontists. Since difficulties arise during their eruption, a plethora of surgical procedures is advocated for their management, including prophylactic extraction. This case series describes the use of midfacial development in 4 patients and illustrates successful patterns of third molar eruption.

The prediction of impacted versus spontaneously erupted mandibular third molars

Background

To evaluate the predictive capacity of orthodontists and oral maxillofacial surgeons (OMFSs) in anticipating the process of impaction or eruption of lower third molars (L3Ms) through the examination of serial panoramic radiographs.

Methods

Sixty-eight lower third molars (L3Ms) were analyzed in 34 orthodontically treated patients without extraction. Twenty-seven OMFSs and 27 orthodontists were randomized in order to analyze the radiographs. Initially, the evaluators issued the prognosis for the L3Ms in XR1, a posterior for the XR1 + XR2. Concordance of the diagnosis was examined using Kappa statistics, and the differences between the groups of evaluators were examined using the chi-square test at p<0.05.

Results

When examining XR1 in cases where the teeth erupted spontaneously, the prognostic accuracy rate for OMFSs and orthodontists was similar, 63 and 65.7%, respectively (p=0.19). When evaluating XR1 + XR2, the accuracy among orthodontists (60%) was similar to that reported for XR1 (p=0.19), while OMFSs presented a reduction in the accuracy (55.3%, p<0.0001). When the L3Ms remained impacted, accuracy in XR1 was lower than in spontaneously erupting L3Ms, although similar between OMFSs (50.1%) and orthodontists (49.1%). Furthermore, for impacted L3Ms, when examining XR1 + XR2, the OMFSs presented a significant higher accuracy (71.8%, p <0.0001).

Conclusions

Orthodontists and OMFSs seem unable to predict spontaneous eruption or impaction of the lower third molars from single or longitudinal x-rays. When adding a second longitudinal x-ray, orthodontists and more significantly OMFSs tend to indicate more extractions.