Relevance of the Variation in the Angulation of Palatal Throat Form to the Orientation of the Occlusal Plane: A Cephalometric Study

Authors: Sanath Kumar Shetty, Sanya Sinha, K. Kamalakanth Shenoy

Abstract:

The posterior reference for the ala tragal line is a cause of confusion, with different authors suggesting different locations as to the superior, middle or inferior part of the tragus. This study was conducted on 200 subjects to evaluate if any correlation exists between the variation of angulation of palatal throat form and the relative parallelism of occlusal plane to ala-tragal line at different tragal levels. A custom made Occlusal Plane Analyzer was used to check the parallelism between the ala-tragal line and occlusal plane. A lateral cephalogram was shot for each subject to measure the angulation of the palatal throat form. Fisher’s exact test was used to evaluate the correlation between the angulation of the palatal throat form and the relative parallelism of occlusal plane to the ala tragal line. Also, a classification was formulated for the palatal throat form, based on confidence interval. From the results of the study, the inferior part, middle part and superior part of the tragus were seen as the reference points in 49.5%, 32% and 18.5% of the subjects respectively. Class I palatal throat form (41degree-50 degree), Class II palatal throat form (below 41 degree) and Class III palatal throat form (above 50 degree) were seen in 42%, 43% and 15% of the subjects respectively. It was also concluded that there is no significant correlation between the variation in the angulations of the palatal throat form and the relative parallelism of occlusal plane to the ala-tragal line.

Keywords: Ala-tragal line, occlusal plane, palatal throat form, cephalometry.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1106703

References:

[1] Glossary of Prosthodontics Terms. J Prosthet Dent 2005; 94 (1) 12- 20.
[2] Walter A. Hall Jr. Important factors in adequate denture occlusion J Prosthet Dent 1958; 8 (5): 764-776.
[3] Boucher CO Ed. Swenson's Complete Dentures, ed. 5, St. Louis, 1964, The C. V. Mosby Company, p. 246-251.
[4] Lunquist DO, Luther WW. Occlusal plane determination. J Prosthet Dent 1970; 23: 489- 498.
[5] Merkeley HJ. The labial and buccal accessory muscles of mastication. J Prosthet Dent 1954; 4: 327.
[6] Cooperman HN. HIP plane of occlusion in oral diagnosis. Dent Surv. 1975; 51: 60-62.
[7] Rich H. Evaluation and registration of the HIP plane of occlusion. Australian Dental Journal 1982; 27: 162.
[8] Swenson MG. Complete Dentures, ed. 2, St. Louis, 1947, the C. V. Mosby Company, p.180.
[9] Wilder, Harris H. Laboratory Manual of Anthropometry, Philadelphia, 1920, P. Blakiston’s Son and Co., p. 4.
[10] Anthony G. Sclar. Soft tissue and Esthetic Consideration in Implant Therapy, Japan, Quintessence Publishing .Co, Inc 2003, Pg 16.
[11] Miller. Removable Prosthodontics 1st Ed., Ontario, Canada, B.C. Deckar, Inc.1988 Pg 221.
[12] Gupta RH, Singh SP. Relationship of anatomical landmarks with occlusal plane. JIPS 2009; 9(3): 142- 147.
[13] Spratley MH. A simplified technique for determining the occlusal plane in full denture construction. J Oral Rehabil 1980; 7(1): 31-33.
[14] Shingli K. Chetal B.R. and Jabade J; Validity of soft tissue landmarks in determining the occlusal plane; JIPS; 2005;5;3;139-145.
[15] Van Niekerk FW, Miller VJ, Bibby RE. Ala tragus line in complete denture prosthetics. J Prosthet Dent 1985; 53(1): 67.
[16] Rostamkhani F, Sahafian A, Kermani H.A Cephalometric Study on the relationship between the Occlusal Plane, Ala-Tragus and Camper’s Lines, in patients with Angle’s Class III Malocclusion. J Dent 2005; 2(2): 46-49.
[17] Sharifi E, Rostamkhani F. A Cephalometric study on relationship between occlusal plane and ala-tragus and Campers plane. Journal of Mashhad Dental School 2000-2001; 24(324): 112-5.
[18] Hartono R. The occlusal plane in relation to facial types. J Prosthet Dent 1967; 17 (6): 544.
[19] Lahori M, Nagrath R, Malik N. A Cephalometric Study on the Relationship between the Occlusal Plane, Ala-Tragus and Camper’s Lines in Subjects with Angle’s Class I, Class II and Class III Occlusion. Journal of Indian Prosthodontic Society Dec 2013;13:4: 494-498.
[20] Kassab NH. The selection of maxillary anterior teeth width in relation to facial measurements at different types of face form. Al–Rafidain Dent J 2005; 5(1): 15-24.
[21] Tandale UE, Dange SP, Khalikar AN. Biometric relationship between intercanthal dimension and the widths of maxillary anterior teeth. J Indian Prosthodont Soc 2007; 7(3): 123- 5.
[22] Al Wazzan KA. The relationship between intercanthal dimension and the widths of maxillary anterior teeth. J Prosthet Dent 2001; 86(6): 608- 12.
[23] Rai R. Correlation of Nasal Width to Inter-Canine Distance in Various Arch Form. J Indian Prosthodont Soc. Jun 2010; 10(2): 123–127.
[24] Hasanreisoglu U, Berksun S, Aras K, Arslan I. An analysis of maxillary Anterior teeth: Facial and dental proportions. J Prosthet Dent 2005; 94(6): 530-38.
[25] Zhu Y, Gu Y, Du R, Li C. Reliability of two methods on measuring root canal curvature. Int China J Dent 2003;3: 118-121.
[26] Millsap CH: The posterior palatal seal area for complete dentures. Dent Clin North Am 1964;8:663-673.
[27] Winkler S. Essentials of complete denture prosthodontics 2nd Ed, USA, 2004, page 204.