Molar Angulation Research Articles

Expansión rápida maxilar en pacientes adultos jóvenes: comparación de aparatos dentosoportados y esqueletalmente soportados. Estudio de cohorte.

Introduction: Maxillary constrictions are one of the most frequent abnormalities, regardless of the type of dentition studied. They can be treated either with tooth-borne or bone-borne expander appliances, depending on the biological maturation of the patient. Treatment during prepubertal stages has been shown to be successful, but there is evidence of an open suture even in late adolescence stages. The aim of this study is to compare the effects of a rapid expansion bone-borne device to a tooth-borne device in young adults suffering from maxillary constriction, by means of Cone-Beam Computed Tomography. Materials and methods: A retrospective observational study was conducted in nine patients (three males, six females) with a mean age of 18±5.5 years, who attended the Dentistry Service of Universidad de Chile during 2014-2015. Six patients were treated with tooth-borne appliances (Hyrax type) and three patients with bone-borne appliances (MARPE). Linear measurements of the anterior and posterior transverse dimension and angular measurements of the inclination of molars and incisors were obtained through CBCT for each group in T1 and T2. Results: A significant increase in the posterior transverse dimensions in both groups was observed. Radiolucency of the suture was observed in all patients treated with miniscrews and in half of the patients treated with Hyrax. Greater angulation of molars was shown in the tooth-borne group in comparison with the bone-borne group. Conclusion: Both appliances caused an increase in the posterior transverse dimension, but bone anchored appliances achieved a more parallel and skeletal expansion. Randomized clinical trials with a larger sample and follow-up are needed.

Effect of mandibular first molar mesialization on alveolar bone height: a split mouth study

ObjectivesTo evaluate the risk of vertical alveolar bone loss (ABL) in mesialized mandibular permanent molars due to space closure in patients with unilateral second premolar agenesis. The contralateral side served as control.Subjects and methodsTwenty-five retrospectively selected subjects (median age 14.9, range 12.0, 31.9 years) were analyzed. Space closure (approximately 10 mm) was performed using skeletal anchorage. ABL was measured at mesial and distal sites of first molars in pre- and post-treatment panoramic radiographs. Measurements were corrected for distortion and magnification of radiographs. Molar angulation according to the occlusal plane was also evaluated. Permutational multivariate analysis of covariance (MANCOVA), followed by pairwise comparisons, was performed.ResultsMANCOVA resulted in no difference in ABL between the distal sites of mesialized molars and the control sites. On the contrary, there was statistically higher ABL, at the mesial sites of mesialized versus non-mesialized molars (p = 0.042; median 0.19 mm; range − 0.82, 1.33); though the difference was not clinically relevant. In the space closure side, mesially, only two patients had ABL higher that 1 mm. No patient had a severe bone level height defect (> 3 mm distance from the cementoenamel junction) at any point.When testing differences in molar angulation between sites and from pre- to post-treatment condition, no significant difference was detected (p > 0.05, median − 1.9°, range − 13.5, 6.2).LimitationsThis is a retrospective study on panoramic radiographs.ConclusionsSpace closure through extensive tooth movement was identified as a risk factor for vertical ABL, at the mesial sites of mandibular first molars. However, the amount of ABL was not clinically relevant, and thus this treatment option is considered safe in terms of ABL.

Associations of pretreatment parameters with changes during orthodontic treatment

To examine whether pretreatment conditions of a patient can determine alveolar bone changes after orthodontic treatment. Cone beam computed tomography (CBCT) images were obtained from 44 patients (17 male and 27 female, 14.02±1.29years). Buccal bone height (BBH), buccal bone thickness (BBT), and molar angulation (MA) of right and left maxillary molars and intermolar distance (ID) were measured using the CBCT images obtained before and after orthodontic treatment using conventional brackets and self-ligating conventional brackets. There was a significant change only in BBH after treatment. All posttreatment parameters had significant positive correlations with the corresponding pretreatment parameters (r2 =0.376-0.719, P<0.001). Most of the changes had significant negative correlations with the corresponding pretreatment parameter (r2 =0.054-0.249, P<0.03). The results were not significantly influenced by the different bracket types. The current findings suggest that the CBCT-based morphological information about dentition and oral bone conditions of patients can provide a better pretreatment plan to estimate the results of orthodontic treatment.

Microimplant Supported Vertical Control Treatment for Skeletal Class I Dolichofacial Patient with Transverse Discrepancy and Anterior Open Bite

Some open bite can be relieved by intrusion of molars in non-extraction approaches, which is usually suggested for patients with acceptable facial profiles or non-hyperdivergent skeletal patterns. In cephalometric analyses, mesial angulation of molars’ axes is frequently observed in patients with open bite. Therefore, a treatment strategy is to correct anterior open bite by both clockwise rotation of maxillary molars and counter-clockwise rotation of mandibular molars, resulting in uprighting and intruding force of molars. Using this manner, clinicians are recommended to reinforce skeletal anchorage by placing microimplants into alveolar bone between the first and second molars. In this case report, we have successfully treated an anterior open bite patient with transverse disharmony by managing vertical dimension using microimplant. (Clin J Korean Assoc Orthod 2019;9(1):34-44)

Comparison of achieved and predicted tooth movement of maxillary first molars and central incisors: First premolar extraction treatment with Invisalign.

To compare achieved and predicted tooth movements of maxillary first molars and central incisors in first premolar extraction cases treated with Invisalign. The present study included 30 patients who received maxillary first premolar extraction treatment with Invisalign. The actual posttreatment model was registered with the pretreatment model on the palatal stable region and superimposed with the virtual posttreatment model. Achieved and predicted tooth movements of maxillary first molars and central incisors were compared using paired t-test. Linear mixed-effect model analyses were used to explore the influence of age (adolescents vs adults), attachment (G6-optimized vs 3-mm vertical, 3-mm horizontal, and 5-mm horizontal), and initial crowding on the differences between predicted and achieved tooth movement (DPATM). First molars achieved greater mesial tipping, mesial translation, and intrusion than predicted. Central incisors achieved less retraction and greater lingual crown torque and extrusion than predicted. Adolescents showed greater DPATM in the mesiodistal translation of first molars and labiolingual translation of central incisors and smaller DPATM in the occlusogingival translation of the first molars and crown torque of the central incisors than adults. The 3-mm vertical attachment group showed greater DPATM in the mesiodistal translation of the first molars vs the G6-optimized attachment group. Initial crowding had an inverse correlation with DPATM in angulation and mesiodistal translation of the first molars. First molar anchorage control and central incisor retraction were not fully achieved as predicted in first premolar extraction treatment with Invisalign. Age, attachment, and initial crowding affected the differences between predicted and achieved tooth movement.

The Effect of Eruption Level and Angulation of Third Molars on Interdental Root Proximity: A Case-Control Study

The Effect of Eruption Level and Angulation of Third Molars on Interdental Root Proximity: A Case-Control Study

Does the Angulation of an Impacted Mandibular third Molar Affect the Prevalence of Preoperative Pathoses?

Statement of the Problem: The removal of a third molar tooth associated with a pathological condition is usually an easy decision. However, it is necessary for clinicians to know about the prevalence of preoperative pathologies associated with impacted mandibular third molars to the identification of the prophylactic approach to be applied to symptom-free impacted third molars.Purpose: The objective was to investigate the effect of the angulation of impacted mandibular third molars on the prevalence of associated pathologies. Materials and Method: In this retrospective study, we examined the panoramic radiographs of 954 patients referred for impacted third molar surgery. A total of 1598 impacted mandibular third molar teeth were included in the study. Pathological conditions included the caries on distal surface of the adjacent second molar, caries on impacted mandibular third molars, bone loss distal to the adjacent second molar, the radiolucent area distal to the impacted mandibular third molar were determined. Results: Caries were observed more in the impacted third molar (18.9%) compared to the adjacent second molar (15.8%). The radiolucent area on distal surface of the impacted mandibular molar was 11%, while the periodontal bone loss distal to the adjacent second molar was 4.9%. Mesioangular-impacted mandibular third molars had high risk of caries development on second and third molar. The prevalence of periodontal tissue damage to the adjacent second molar was higher in horizontal and mesioangular angulation. Vertical and distoangular-impacted mandibular third molars had high risk for bone loss at distal aspect. Conclusion: The prevalence rate of pathological conditions in mesioangular impacted teeth was higher.

Radiographic prediction of mandibular third molar eruption and mandibular canal involvement based on angulation.

The aim of our study was to identify and predict patients at risk of impeded mandibular third molar eruption and potential relation between the third molar roots and the mandibular canal, based on molar angulations in an early development stage. A total of 1011 adolescent orthodontic patients were included in this longitudinal study. We analysed pre-eruptive rotational changes and root development of mandibular third molars on 2022 panoramic radiographs (two time-points). Five variables were evaluated: third molar eruption level, development stage, risk of relation between the third molar and the mandibular canal, the molar angulations and orthodontic treatment. The relation between early third molar angulation and mean annual angulation change was assessed using a linear mixed model. Logistic regression was applied to investigate a potential correlation of the radiographic variables with the eruption potential and risk of developing a relation between the third molar and the mandibular canal. Mandibular third molar follicles with an initial angulation exceeding 27.0° relative to the second molar tend to progressively increase their angulation during further development. A significant correlation was found between the hemimandibular molar angulations and the probability of eruption (P<0.0001). The second to first molar angulation was predictive for potential development of a relation with the mandibular canal (P=0.005). From the present data, it appears that severely angulated mandibular third molars (>27.0°) have a minimal chance of future eruption and a maximal risk of developing a relation with the mandibular canal.

Preoperative Anatomic Evaluation of the Relationship Between Inferior Alveolar Nerve Canal and Impacted Mandibular Third Molar in a Population of Bhubaneswar, Odisha, Using CBCT: A Hospital-Based Study.

To evaluate the correlation between the position of inferior alveolar nerve canal and the angulation of impacted mandibular third molars using cone beam computed tomography (CBCT) in a hospital-based study in the state of Odisha, India. Three hundred cases of impacted third molars in 200 patients (154 males; 46 females) were included in the study, for whom an initial periapical or panoramic radiograph had revealed that the mandibular canal and the lower third molars were in close proximity. A CBCT scan of each patient was carried out to assess how the canal position influenced the class and position of impaction, angulation of impaction and bone contact. Class II position B impactions were found in 78.37% cases where the position of ID canal was approximate to the lingual plate and inferior to third molar (73.75%). The results were statistically significant (p = 0.00). 80% of the ID canals showed bone contact. Of these 73.75% ID canals showed lingual bone contact. Mesioangular impactions were most common in mandible and significantly associated with lingual and inferior positioning of the canal. The study mostly exhibited patients having mesioangular class II position B third molar impactions of the mandible. The position of the canal has a significant influence on the type of impaction and the bone contact.

Change in alveolar bone level of mandibular second and third molars after second molar protraction into missing first molar or second premolar space.

SummaryObjectiveTo investigate the factors associated with the change in alveolar bone level of mandibular second and third molars after second molar protraction into the space of the missing first molar (L6) or second premolar (LE).MethodsFifty-one patients in whom space of the missing L6 or LE was treated with second molar protraction (13 males, 38 females, mean age 19.6 ± 4.7 years) from 2003 to 2015 were included. The alveolar bone level and position and angulation of the mandibular second and third molars were measured in panoramic radiographs at pre-treatment (T1), and after the alignment of the third molars following second molar protraction (T2). Factors associated with alveolar bone loss on the distal aspect of the mandibular second molars were assessed using linear regression analysis.ResultsAge at T1 (P < 0.001) and third molar angulation at T1 (P = 0.002) were significant factors for the prediction of alveolar bone level distal to the second molars.LimitationThis study used two-dimensional panoramic radiographs, and we could observe only the interproximal bone level.ConclusionsAfter second molar protraction into the missing first molar or second premolar space, mandibular second molars may exhibit alveolar bone resorption in the distal root in older patients and in those with mesially tilted third molars before treatment.

Short-term cone-beam computed tomography evaluation of maxillary third molar changes after total arch distalization in adolescents.

Our objectives were to evaluate changes in the position of maxillary third molars with cone-beam computed tomography images in adolescents after total arch distalization using a modified C-palatal plate (MCPP) and to compare them with the changes in a matched control group. We included 68 maxillary third molars of 40 adolescent patients (mean age, 12.6years). They were divided into MCPP and control groups. Cone-beam computed tomography images were taken before and after molar distalization (mean duration, 14.4months) in the MCPP group and also in the control group (mean duration, 12.9months). The changes in the position, angulation, and rotation of the third molars were assessed, and the volumes of maxillary tuberosity were measured. After distalization, the third molars moved backward (1.2mm) and upward (0.5mm) in the MCPP group with a significant difference (P<0.003), and they moved downward and forward in the control group. The changes in rotation and angulation were insignificant. The volumes of maxillary tuberosity increased in both groups. Maxillary total arch distalization caused unerupted third molars to move backward and upward, with an insignificant difference in the posttreatment volume of maxillary tuberosity. Therefore, it may be possible to perform maxillary total arch distalization in adolescents with unerupted third molars without a germectomy, at least in the short term.

Relationship of Mandibular Third Molar to Mandibular Anterior Crowding

Abstract Introduction The impact of third molars in occurrence of secondary mandibular incisor crowding has been a disputable subject and is reviewed in the dental literature for many years. The relationships between lower third molar angulation, eruption level, and eruption space to lower anterior crowding are not completely understood. Aim To evaluate the relation between the third molar angulations, eruption space, eruption level, and mandibular anterior crowding. Materials and Methods Pretreatment plaster study models (mandibular dental arches) and orthopantomograph of 40 individuals, aged between 12 and 22 years, were part of the study. The whole sample was divided into two groups based on the Little's index of irregularity: group I—control group (n = 20) composed of patients with index 0 to 3 mm, and group II—study group (n = 20) composed of patients with index &gt; 3 mm. Calculations were made for the third molar eruption depth, eruption space, and angulation. Statistical Analysis Mean values were compared for selected dimensions between the control and study groups with Student's t-test. Results Statistically significant differences for Ganss ratio in right side between the control and study groups with a p-value of 0.049 were observed. Statistically insignificant difference was seen between the control and study groups for other parameters. Eruption level B was found for maximum molars in the study group, 95% on right and 85% on left side. Conclusion It was inferred that no strong relation exists between the third molar eruption level, space, and angulations to mandibular anterior crowding.

Effect of extraction or nonextraction orthodontic treatment modality on favorability of eruption of impacted third molars.

The objective of the study is to determine if extraction of permanent teeth, for orthodontic purpose, causes a change in third molar angulation and also to determine if extraction of permanent teeth causes an increase in eruption space available for third molars. This systematic review includes retrospective cohort studies which evaluated the change in third molar angulation or eruption space available for third molars among orthodontic patients treated by a fixed appliance with either extraction or nonextraction protocol. Search engines used were MEDLINE, IndMED, Web of Science, Cochrane, EMBASE, and Google Scholar from the year 1975 to 2015. Separate data collection forms were used to extract data from the studies. The Cochrane Risk of Bias Assessment Tool was used to assess the studies included in the systematic review. Fifteen studies included in the systematic review proved that third molar angulation and eruption space improved in patients treated with extraction treatment modality. However, two studies concluded that change in third molar angulation and eruption space occurred irrespective of the type of treatment involved. The angulation and eruption space of third molar improved following extraction of premolar or molar. Nonextraction treatment modality did not cause any adverse effects.

Prevalence of impacted third molars among orthodontic patients in different malocclusions.

The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction and missing third molars in patients over 18 years in different anteroposterior skeletal patterns among central Indian populations. The study reviewed 357 orthopantomograms of patients attending the Government College of Dentistry, Indore, Madhya Pradesh. Patients were evaluated to determine the prevalence of third molar impaction, angulation, and level of eruption in Class I, Class II, and Class III patients using Winter's classification to determine angulation of third molars and Pell and Gregory classification for level of impaction. Out of 357 patients, 187 (52.3%) were present with at least one impacted teeth. The third molar impaction was most commonly present in Class II malocclusion (60.65%). Overall, the most common angulation of impaction in both genders was the mesioangular (39%), and the most common level of impaction in both arches was Level B. In Class I, Class II and Class III malocclusion vertical angulation was the most common finding in the maxillary arch and mesioangular angulation in the mandibular arch. No significant association was observed between different types of malocclusion and third molar impaction (P > 0.4648). This study found that almost half of the adult patients above 18 years had at least one impacted third molar. The anteroposterior relationship does not have any significant role for the third molar impaction.

Pattern of impacted third molars and their associated radiographic pathological lesions in Makkah region: a retrospective radiographic survey

Background: In recent centuries the wisdom tooth impaction of both jaws considered a public health problem, because lack of space to erupt normally or even to appear in the oral cavity, this sequela may be due to insufficient activity of the jaws over the centuries. Aim of the Study: The purpose of this study was to determine the prevalence of impacted wisdom associated with pathologies in relation to angulation of impaction in an adult Saudi population in Mecca area, Materials and Methods: This is a cross sectional study in which records of 4000 patient’s panoramic radiographs between 2017 -2018 from OPG & CEPH X-Ray Department. Umm Al-Qura University-Dental College and Hospital were reviewed. Finally, 411 out of 4000 patient’s radiographs which showed impacted wisdom were selected. Data related to the type of impaction in both jaws and associated pathologies were then collected, tabulated and analyzed. Results: Panoramic radiographs of 4000 patients aged 25-60 years were examined. A total of 411 (10.27%) demonstrate the presence of at least one impacted third molar. The study demonstrates that the highest number of impactions related to mandibular arch followed by maxillary arch then the least common cases with impaction related to both jaws. For the angulation of the impacted third molars, the most common angulation was vertical folwed by mesioangular and distoangular angulations were the less common, while the least common angulation was Horizontal. The most angulated wisdom associated with pathologies was the mesioangular angulation followed by vertical then the least common pattern distoangular and horizontal. The other angulations were negligible. The most common radiographic features of lesions associated with the third molar were radiolucent lesions Followed by radiopaque lesions. And the least common lesions were mixed lesions. Conclusion: The radiographic features of impacted wisdom angulation could be correlated to their pathologies among all cases in Makkah region.

Skeletal changes after rapid maxillary expansion in children with obstructive sleep apnea evaluated by low-dose multi-slice computed tomography

ObjectiveThe objective of this study was to evaluate the skeletal effects of rapid maxillary expansion (RME) therapy performed using teeth as anchors, in obstructive sleep apnea (OSA) children, by low-dose computed tomography (CT) of the midpalatal suture opening, maxillary base width, nasal cavities width, first molar angulation and, unlike most studies in the literature, on the pterygoid processes distance. MethodsFourteen children (mean age 8.68 years) with OSA presenting a malocclusion characterized by upper-jaw contraction had 16-Multislice CT (MSCT) scans taken before (T0) and after (T1) RME. All exams were performed using a rigid protocol to ensure reproducibility of image collection over time, with a 16-row MSCT scanner equipped with a Dentascan reconstruction program. Scanning parameters were as follows: scout view in the anteroposterior (AP) and laterolateral (LL); 1.25-mm slice thickness with 0.6-mm collimation from the dentoalveolar and basal areas of the maxilla up to the nasal cavity, parallel to the palatal plane; 80 kV, 100 mA with an 11.25-mm table speed/rotation, rotation time 0.6 s. Matrix size was 512 × 512. ResultsOpening of the midpalatal suture was demonstrated in all cases. The results showed statistically significant T0 to T1 increments in all treated cases and clear imaging findings. ConclusionUse of three-dimensional (3D)-CT for follow-up studies requires a very rigid protocol to maintain reproducible positions in the scanner over time. The images confirm the real remodeling of craniofacial structure. However, to be valid such an imaging approach needs great attention to reproducibility of anatomic images over time. The changes in volume of the UA, even with a rigid protocol, cannot be affirmed with 3D-CT. There is a need to improve the definition of markers using this imaging approach when performing longitudinal studies; currently this issue is unresolved.

Relationship Between Third Mandibular Molar Angulation and Distal Cervical Caries in the Second Molar.

Third lower molar partially erupted is commonly encountered in dental practice. This situation challenges clinicians with the dilemma whether to remove or to monitor it, because this molar can cause pathology of the adjacent second molar. The aim of this retrospective study is to evaluate the relationship between third mandibular molar and distal cervical caries in second molar. This retrospective study analyzed 55 digital orthopantograms of adult patients and a total number of 95 mandibular third molars were assessed for eruption status, angulation, radiographic evidence of caries or restoration in the mandibular third molar, and radiographic evidence of caries or restoration in the distal surface of the mandibular second molar. The distal cervical caries in second molar is associated with fully erupted and partially erupted wisdom molar in horizontal, mesioangular and vertical position and less with presence of caries in third molar. There are caries lesions in distal second molars in mesioangular position when adjacent third molar is caries free.

Effect of posterior space discrepancy and third molar angulation on anterior overbite.

In this study, we aimed to determine the effect of maxillary and mandibular posterior space discrepancies and third molar angulations on the overbite. Pretreatment lateral cephalograms of 131 subjects were analyzed. The sample included 83 open-bite and 48 deepbite subjects. A multiple regression analysis was used to evaluate the influence of maxillary and mandibular posterior space discrepancies and third molar angulations (predictor variables) on overbite. Correlations between posterior space discrepancy and third molar angulation, and correlations between predictor variables and dental angulation and height of posterior teeth and incisors were evaluated with the Pearson correlation coefficient. Subgroups with accentuated negative overbite and deepbite (27 open-bite, 37 deepbite) were compared with t tests. The multiple linear regression analysis showed a positive association of the mesial angulation of the mandibular third molar with overbite. Posterior space discrepancy was negatively associated with posterior teeth mesial angulation and dentoalveolar height. However, these associations were weak, with no clinically significant implications. The deepbite subgroup showed significantly greater mesial angulation of the mandibular third molars than did the open-bite subgroup. There was no clinically significant effect of posterior space discrepancies and third molar angulations on overbite and dental angulation and height of posterior teeth and incisors.

Mesioangular impacted lower third molar angulation changes in non-extraction orthodontic treatment

The lower third molar is the most commonly impacted tooth, with higher prevalence in the mandibular and mesioangular angulation. In orthodontic patients, the observation of third molar impaction generally entails measurement of its angulation before and after treatment. This study aimed to determine mesioangular impacted lower third molar angulation changes in subjects with fixed orthodontic treatment in Teaching Dental Hospital, Faculty of Dentistry, Universitas Indonesia. 27 samples were selected and measured before and after treatment on panoramic radiograph using the Poosti method. The result showed an increase in angulation clinically on both sides of the jaw. Based on statistical analysis, however, these angulation changes were not significant (p > 0.05).

Effects of facemask therapy on the mandibular retromolar space. A follow-up study.

Objectives:To evaluate the mandibular retromolar space after facemask therapy and a follow-up period.Methods:This retrospective study was conducted between May and September in 2014. The sample consisted of pre-treatment (T1), post-treatment (T2), and follow-up(T3) panoramic radiographs of 19 skeletal and dental Class III patients (7 female, 12 male; mean age: 10.5 years) treated with facemask and a removable intraoral upper appliance in the Faculty of Dentistry Gazi University, Ankara, Turkey. Each patient’s lower arches were evaluated as right and left segments. As third molars were congenitally absent in 3 segments, a total of 35 segments were evaluated. The average treatment time was one year. The average follow-up period was 2.4 years. The positions, angulations, dental maturations of lower third molars, and mandibular retromolar spaces (DJ) were assessed. Friedman’s 2-way Analysis of Variance, multiple-comparison, Pearson’s correlation, and Chi-square tests were used for statistical evaluation. A p<0.05 was considered as significant.Results:The angulation of the first molar (¡) increased significantly only in the follow-up period (T3). Mandibular retromolar spaces were increased significantly during all periods. The most commonly determined position of the third molar, by Winter’s classification, was vertical angulation in all periods. Moderate and significant correlations were found between third molar angulation(ß) and DJ at T2 and T3. Significant correlations were also found between DJ and Demirjian classification stages during all periods.Conclusion:Facemask therapy did not have an adverse effect on the mandibular retromolar space during treatment and follow up periods.