A quantitative research on clinical parameters of gingival contour for anterior teeth esthetic analysis and design.

OBJECTIVES: To provide reference for computer-aided esthetic analysis and design of the maxillary anterior teeth. MATERIALS AND METHODS: Intraoral scanner was used to obtain the maxillary three-dimensional digital models of subjects with healthy periodontal tissue. In SpaceClaim, the occlusal plane was established as the horizontal reference plane to measure the positional relation between the gingival zenith (GZ) of the maxillary anterior teeth, the angle formed between the gingival line and the maxillary midline (GLA), the distance between the GZ of the lateral incisor and gingival line (LID), and the distance between the GZ and the vertical bisected middle surface along the long axis of the clinical crown (VBMS). RESULTS: The GLA was 92.7 ± 3.2°. The GZ of the canine, lateral incisor, and left central incisor were located to the GZ of the right central incisor coronally at 0.68 ± 0.91, 0.65 ± 0.66 mm, and apically at 0.12 ± 0.42 mm, respectively. The LID was 0.65 ± 0.92 mm. The GZ of the canine, lateral incisor, and central incisor were located distally to the VBMS at 0.00 ± 0.06, 0.27 ± 0.19, and 0.73 ± 0.21 mm, respectively. CONCLUSION: The GZ at different tooth position are in different heights. The direction and degree of the GZ deviation from the VBMS are also related to tooth position. CLINICAL SIGNIFICANCE: The clinical parameters of the gingival contour obtained in this research can be used for patients with unsound contour of periodontal soft tissue to do the anterior teeth esthetic analysis. Besides, it can also be used to determine the proper position between the GZs of the maxillary anterior teeth in anterior teeth esthetic design.

Influence of inner circular sealing area impression method on the retention of complete dentures.

The aims of the present study were to describe an impression method of "inner circular sealing area" and to evaluate the effect of the method on retention, aesthetics and comfort of complete dentures, which lack labial base for patients with maxillary protrusions. Three patients were subjected to the experiment, and two sets of complete maxillary dentures were made for each patient; the first set was made without labial base via an inner circular sealing area method (experimental group) and the second had an intact base that was made with conventional methods (control group). Retention force tests were implemented with a tensile strength assessment device to assess the retention and a visual analogue scale (VAS) was used to evaluate the comfort between the two groups. Results showed larger retention force, better aesthetics and more comfort in the experimental group. The improved two-step impression method formed an inner circular sealing area that prevented damage to the peripheral border seal effect of the denture caused by incomplete bases and obtained better denture retention.

Influence of Inner Circular Sealing Area Impression Method on the Retention of Complete Dentures

The aims of the present study were to describe an impression method of "inner circular sealing area" and to evaluate the effect of the method on retention, aesthetics and comfort of complete dentures, which lack labial base for patients with maxillary protrusions. Three patients were subjected to the experiment, and two sets of complete maxillary dentures were made for each patient; the first set was made without labial base via an inner circular sealing area method (experimental group) and the second had an intact base that was made with conventional methods (control group). Retention force tests were implemented with a tensile strength assessment device to assess the retention and a visual analogue scale (VAS) was used to evaluate the comfort between the two groups. Results showed larger retention force, better aesthetics and more comfort in the experimental group. The improved two-step impression method formed an inner circular sealing area that prevented damage to the peripheral border seal effect of the denture caused by incomplete bases and obtained better denture retention.

O objetivo deste caso foi descrever um método de impressão por "área de selamento circular interno" e avaliar o efeito deste método na retenção, estética e conforto de próteses totais sem base labial para pacientes com protrusão maxilar. Três pacientes foram objeto desta experiência e foram feitas duas próteses maxilares completas para cada um deles; a primeira foi elaborada sem base labial pelo método de área de selamento circular interno (grupo experimental) e a outra teve uma base feita pelo método convencional (grupo controle). Foram realizados testes de retenção com estudo de tensão para avaliar a retenção e para avaliação do conforto dos dois grupos, foi empregada a escala analógica visual (EAV). Os resultados demonstraram que o grupo experimental apresentou força de retenção maior, estética melhor e mais conforto. O método modificado de impressão em duas etapas formou uma área de selamento circular interno que evitou danos ao selamento periférico causados por bases incompletas e obteve melhor retenção da prótese.