Maxillary Anterior Teeth Dimensions and Relative Width Proportions: A Narrative Literature Review.

Predictable results in the aesthetic treatment of anterior teeth can be obtained by resorting to the concept of dental aesthetics and, in particular, defining the ideal tooth dimensions and proportions to obtain a harmonious smile. Considering the great variety of articles dealing with the topic, and the lack of updated reviews, this narrative literature review aims to evaluate current knowledge on anterior teeth dimensions and to verify the existence and the potential applications of the anterior teeth proportioning theories (Golden Proportion, Golden Percentage, RED Proportion, and Golden Rectangle). PubMed, Embase, Cochrane Library, and Google Scholar databases were comprehensively searched using different keywords and term combinations. The research includes articles published up to June 2023, no time limits were set, and only articles in English were included. Inclusion criteria comprehended reviews, clinical studies, and in-vitro studies. A total of 66 articles were selected. Two main topics were identified: "Anterior teeth dimensions", "Golden Proportions, Golden Percentage, RED Proportions, and Golden Rectangle". As far as tooth dimensions are concerned, different width ranges are recognized for men and women and for different ethnic groups. Perfectly symmetric contralateral elements are found in low percentages of subjects. The correlation between dental dimensions and facial parameters is not always present, and it strongly depends on the sample's ethnicity and gender. Ideal tooth proportions were only partially identified.

Accuracy of Digital Impressions in Fixed Prosthodontics: A Systematic Review of Clinical Studies.

PURPOSE: To determine the accuracy of direct digital impressions in vivo and compare it to that of conventional impressions in order to assess whether intraoral scanners could be a legitimate alternative for the manufacturing of fixed prosthodontics. MATERIALS AND METHODS: An electronic systematic search was conducted in the PubMed, Web of Science, Embase, and Cochrane Library databases using query terms such as digital impression; intraoral digital impression; intraoral scanner; intraoral digital scanner; conventional impression; analogue impression; and accuracy. The outcomes were the trueness and precision of digital impressions in comparison to those of high-precision conventional impressions in vivo. RESULTS: Six studies matched the inclusion criteria. Four studies investigated the precision of digital impressions, while two studies focused on their trueness. Even if all the authors agreed that conventional impressions were more accurate than digital impressions in vivo, they gave different opinions on using intraoral scanners in a clinical context without causing misfit of the final restoration. CONCLUSION: According to the results of the present review, conventional impressions performed using high-precision impression materials showed greater accuracy than digital impressions. However, additional studies assessing the accuracy of digital impressions in a wider variety of clinical situations are highly recommended.