Cusp Of Maxillary First Molar Research Articles

Comparison of three-dimensional position of maxillary dentition model treated with two digital transfer methods

Objective: To compare and evaluate the difference in maxillary dentition position using an anatomical facebow and jaw movement analyzer. Methods: From March to May 2023, 15 medical interns from Yantai Stomatological Hospital were recruited, including 9 males and 6 females, aged 20-25 years. Digital models and plaster models of maxillary dentition were obtained from the 15 medical interns. The anatomical facebow group (AFB) and jaw movement analyzer group (JMA) were used to transfer the position of the maxillary dentition to the virtual articulator. The virtual occlusal articulator module of exocad denture design software was used to measure the inclination angle of the occlusal plane of the two groups, the distance between the mesio-incisal angle of the left maxillary central incisor and the lateral center point of the lateral condylar sphere of the virtual occlusal articulator, the distance between the mesial buccal cusp of the maxillary first molar and the lateral center point of the lateral condyle sphere of the virtual articulator. The same marks (mesial incisor point of left maxillary central incisor and mesial buccal cusp point of both maxillary first molars) were measured in two groups of maxillary dentition, and the root-mean-square error between 3 points was calculated. Results: The occlusal plane inclination angle in AFB group (9.11°±3.85°) was significantly larger than that in JMA group (4.94°±2.69°) (t=10.45, P<0.001). There were significant differences between AFB and JMA groups. The distances from the mesial cusp of the left first molar to the lateral center of the left condylar, from the mesial cusp of the left maxillary central incisor to the lateral center of the left condylar[(91.75±3.05), (129.09±4.60) mm]were significantly smaller than those in the JMA group[(95.68±5.45), (132.41±5.64) mm](t=-4.48, P=0.001; t=-4.21, P=0.001). In both groups of models, the distance of the mesial cusp of the left maxillary central incisor was (8.81±2.56) mm, and the distance between mesial buccal cusp of maxillary left first molar was (7.56±2.49) mm, the distance between mesial buccal cusp of maxillary right first molar was (7.13±2.77) mm; the root mean square error was (7.93± 2.94) mm. Compared with 0, the difference was statistically significant (t=10.45, P<0.001). Conclusions: There were differences between the two methods (anatomical facebow and the jaw movement analyzer) for transferring the maxillary dentition position to the three-dimensional space position of the virtual articulator.

MANAGEMENT OF FRACTURED FUNCTIONAL CUSP OF MAXILLARY FIRST MOLAR: A CASE REPORT

18Feb 2020 MANAGEMENT OF FRACTURED FUNCTIONAL CUSP OF MAXILLARY FIRST MOLAR: A CASE REPORT Anwetakshmi Ray , Karthik Shetty , Anirudh Garg and Priyanka Kenkare Post Graduate Student, Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Opposite Josallukas Showroom, Light House Hill Road, Hampankatta, Mangalore- 575001, Karnataka (India). Professor and Head of Department, Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Opposite Josallukas Showroom, Light House Hill Road, Hampankatta, Mangalore- 575001, Karnataka (India).

MANAGEMENT OF FRACTURED FUNCTIONAL CUSP OF MAXILLARY FIRST MOLAR: A CASE REPORT

11Feb 2020 MANAGEMENT OF FRACTURED FUNCTIONAL CUSP OF MAXILLARY FIRST MOLAR: A CASE REPORT Anwetakshmi Ray , Karthik Shetty , Anirudh Garg and Sreelakshmi Pradeep

Reliable Ala-Tragus Line for the Orientation of Occlusal Plane by Cephalometry

Introduction: The aim of the study was to determine the most reliable ala-tragus line for the orientation of the occlusal plane in edentulous patients during complete denture fabrication by cephalometry.&#x0D; Materials and Methods: Lateral cephalometric radiographs of 37 dentate subjects were taken at maximum intercuspation. Steel balls were used as radio opaque markers which were adhered to superior border, middle point, and inferior border of tragus as well as the inferior border of ala of nose. Lead foil was cemented to cover the mesio-palatal cusp of maxillary first molar. Tracings of cephalogram were done. Angle between ala-tragus superior, ala-tragus middle and ala-tragus inferior in relation to occlusal plane were measured. Variables were determined and data were analyzed using SPSS version 17 (SPSS, Inc. Chicago, III).&#x0D; Results: The angle formed between occlusal plane and ala tragus middle had lowest mean value of 2.39°. The highest was measured with ala tragus superior 5.18°, while the angle formed with ala tragus inferior was 3.60°. The differences between the three planes in relation to the occlusal plane were significantly different in total subjects as well as in both males and females (p &lt; 0.001).&#x0D; Conclusion: Statistical analysis showed that the middle point of the tragus with the inferior border of the ala of the nose was most accurate in orienting the occlusal plane.

Validity of intraoral soft tissue landmarks as reference points for orientation of occlusal plane in natural dentition: A clinical study

Introduction: Occlusal plane is the average plane established by incisal and occlusal surfaces of teeth. Various anatomic landmarks are used to determine this missing component of occlusion which is lost with the loss of teeth. However, variation has been observed in the orientation of occlusal plane determined clinically with different anatomical landmarks as references. Objective: This study was undertaken to determine the relation of intraoral anatomic soft tissue landmarks, namely, retromolar pad and parotid papilla with occlusal plane in natural dentition. Materials and Methods: Irreversible hydrocolloid impressions of 100 edentulous individuals (50 males and 50 females) were made to get the models. A 16 gauge wire was extended from mandibular occlusion plane posteriorly up to retromolar pad to establish their relationship. Furthermore, vertical distance of apex of parotid papilla to maxillary molar cusp tip it opposed (distobuccal cusp of maxillary first molar or mesiobuccal cusp of maxillary second molar), and mandibular molar cusp tip (to which parotid papilla apposed) was measured when the teeth were in maximal intercuspal position. Results: This study determined that the natural occlusal plane is oriented posteriorly at the level corresponding with the lower third of retromolar pad. Mean distance of parotid papilla above the corresponding maxillary cusp tip (while in occlusion) was 5.048 mm, and mean distance of Parotid papilla above the corresponding mandibular molar cusp tip (while in occlusion) was determined to be 3.602 mm. The difference in observed means between males and females or between right and left side was not statistically significant.