Association Of Impacted Third Molars With Facial Growth Patterns Among Adult Indian Patients - A Retrospective Study

Introduction: The third molar (3M) varies more than other molars in terms of shape, size, timing of eruption, and tendencytoward impaction. Hence, studies need to be carried out to clarify the association of the various patterns of facial growth withmandibular 3M impaction.Purpose: The purpose of this study is to relate the level of impaction of mandibular 3Ms and their inclinations to various patternsof facial growth among Indian patients.Materials and Methods: A total of 207 lateral cephalograms and optic pathway gliomas (OPGs) of patients were obtainedfrom NISSAN Radiological and Diagnostic Centre. The OPGs were analyzed by a single examiner as per: (1) Angulations(using Quek’s analysis - beta angle, 2003). (2) Depth of 3Ms. The lateral cephalograms were assessed by a single examinerusing: (1) Down’s analysis. (2) Beta angle. (3)Jarabak’s ratio. (4) Bjork’s analysis.The subjects were further classified into skeletal Class I, II, and III as well as into horizontal, vertical, and normal growth patterns.The final study data were subjected to a Pearson correlation test to check the association between the 3M impactions andvarious angles. The values found significant were coded into ordinate data and Kendall’s Tau-B Test was done.Results: Statistically, significant correlation was found between depth of impacted mandibular 3Ms and facial angle, Y-axis,cant of occlusion, angle of convexity, and gonial angle.Conclusion: Greater incidence of 3Ms was found to be at position B and C in Class II patients as compared to Class I and IIIpatients. Furthermore, patients showing vertical growth pattern were found to have increased percentage of mandibular 3Mimpactions.

Cephalometric study of the effect of cervical pull headgear based on facial growth patterns / 대한치과교정학회지

The purpose of this study is to investigate the negative effects of cervical pull headgear and to compare the differences between the two groups of growers-vertical grower and horizontal grower group-which are classified by the posterior-anterior facial height ratio. Initial and final lateral cephalograms were taken for 26 patients including 15 vertical growers and 11 horizontal growers ; also, 3 angular measurements and 4 linear measurements were evaluated. The following results were found. 1. The palatal plane was tipped anteroinferiorly in the vertical grower group. 2. The posterior facial height/anterior facial height ratio was increased in the horizontal grower group. 3. The Mandibular plane angle remained stable on both groups. 4. There was no significant difference between the two groups in the amount of maxillary molar extrusion.

Treatment effect of protraction head gear on skeletal Class III malocclusion / 대한치과교정학회지

Before 1970, mandibular overgrowth was known as main cause of skeletal Class III malocclusion in growing children ; however, recent study reports that many skeletal Class III malocclusion patients also show maxillary deficiency. Since 1972, when Delaire re-accommodated Protraction Head Gear (P.H.G.), many researchers have reported that skeletal Class III discrepancies could be corrected through use of P.H.G., which induces anterior movement of maxilla and change in mandibular growth pattern into infero-posterior direction ; nevertheless, it is very difficult to predict resultant changes of orofacial region. The purpose of this study was to find out what treatment effect P.H.G. has on different study samples. Author divided 51 skeletal Class III malocclusion patients with maxillary deficiency who were treated with P.H.G. into different study groups depending on sex, treatment beginning age, intraoral appliance, and facial growth pattern. By doing so, following results were obtained. 1. Treatment beginning age and Sex Four age groups (5.8 to 8 year-old, 8 to 10 year-old, 10 to 12 year-old, 12 to 14 year-old) were compared, and no significant difference was observed. (p<0.05) There was no significant difference between the sex groups, either. (p<0.05) 2. Intraoral appliance Treatment effects of study groups that used R.P.E.(mean age of 10.2) and Labio-Lingual appliance(mean age of 8.9) were compared. There was no significant difference depending on the type of intraoral appliance that was used. (p<0.05) 3. Facial growth pattern 1) Amounts of SNB and ANB corrections were smaller in clockwise growth pattern group than those in normal or counterclockwise growth pattern group. (p<0.05) 2) Amounts of increase in Wits appraisal and mandibular plane angle were greater in counterclockwise growth pattern group than those in normal or clockwise growth pattern group.(p<0.05) 3)Amounts of increase in articular angle were greater in counter lockwise growth pattern group than those in clockwise growth pattern group. (p<0.05)