연마면 인상 채득에 의한 하악 총의치의 설측 형태

Abstract

Objectives: The aim of the present study was to analyze the shapes of lingual polished surface in lower complete dentures formed by polished surface impression, and to provide reference data that can be used when manufacturing preformed edentulous tray and lower complete dentures.

Material and methods: Twenty-six patients with mandibular edentulism were studied. After lower wax dentures were manufactured by conventional methods, the wax was removed from the lingual side of lower wax denture and lingual polished surface impression with tissue conditioner was obtained. Definitive denture was scanned by 3D scanner and scanned images were obtained. After taking slices through the occlusal plane, and vertical slices through the lingual frenum, left and right lateral incisors, 1st premolars, 1st molars, and the anterior border of the retromolar pads, points were marked at the gingival margin of the artificial teeth(a), the maximum bulge of the polished surface(b), and the most inferior point of the lingual border(c). The following 8 measurements were taken: the vertical distance from ac to b(A), the vertical distance from the occlusal plane to b(B), the vertical distance from b to c(C), the vertical distance from the occlusal plane to c(D), the ratio of C to D(E), the angle between ab and the occlusal plane(F), the angle between bc and the occlusal plane(G), and the angle between ab and bc(H).

Results: Each patient showed similar values for the same areas on the left and right sides, without a statistically significant difference. The average values of A were 4.72 ± 1.51 mm at the lingual frenulum, 5.44 ± 1.27 mm at the lateral incisors, 4.80 ± 0.85 mm at the premolars, 3.44 ± 1.04 mm at the molars, and 2.79 ± 0.78 mm at the anterior border of the retromolar pads. The average values of B were 7.78 ± 2.1 mm, 8.45 ± 2.44 mm, 9.91 ± 2.17 mm, 13.87 ± 2.63 mm and 15.07 ± 2.48 mm. The average values of C were 7.74 ± 2.91 mm, 7.80 ± 2.98 mm, 8.17 ± 2.56 mm, 6.60 ± 2.55 mm and 3.96 ± 1.83 mm. The average values of D were 15.52 ± 2.43 mm, 16.25 ± 2.31 mm, 18.08 ± 2.41 mm, 20.47 ± 2.38 mm and 19.03±3.00mm. The average values of E were 0.49±0.15, 0.47±0.15, 0.45 ± 0.12, 0.32 ± 0.12 and 0.20 ± 0.80. The average values of F were 29.87 ± 8.22°, 31.46 ± 10.70°, 43.50 ± 9.74°, 64.08 ± 9.34° and 73.96 ± 5.28°. The average values of G were 96.04 ± 18.05°, 102.51 ± 16.26°, 105.83 ± 12.06°, 110.68 ± 15.17° and 117.75 ± 7.98°. The average values of H were 113.83 ± 14.86°, 107.90 ± 11.38°, 117.05 ± 10.26°, 131.49 ± 10.10° and 136.25 ± 9.44°.

Conclusions: The left and right polished surfaces had similar shapes in each patient. The shape of the mandibular lingual polished surface was not flat or concave, as conventionally manufactured, but was convex at the lingual frenulum, lateral incisors, and 1st premolars, and gradually flattened towards the 1st molars and the retromolar pads. The maximum bulge of lingual polished surface at the lingual frenum was located halfway between the occlusal plane and lingual border, it moved gradually in a downward direction and was located one-fifth at the retromolar pad. The slope from the occlusal plane to the maximum bulge of lingual polished surface was increased in progressing from the lingual frenum towards the retromolar pads. The shapes of polished surfaces investigated in this study can be referred to when manufacturing preformed edentulous tray and taking an impression in patients. This will help to improve the retention and stability of dentures manufactured from a polished surface impression.