Dentogingival Alterations and Their Influence on Facial and Smile Attractiveness.

AIM: This study aimed to evaluate the influence of labial and dentogingival characteristics on facial and smile attractiveness. MATERIALS AND METHODS: Four different close-up photographs each of six women models with different labial and dentogin-gival characteristics were obtained. One of the models was considered standard. Photographs were arranged in an album were evaluated by 100 laypersons, and 30 dentists who ranked each close-up of the models from according to the degree of attractiveness from first to sixth place, with first being the model considered most attractive and justified the reasons for choosing. RESULTS: The standard model received the best scores for both lips (7.75) and face (5.18). Medium-sized lips were preferred (p < 0.05), and the smile positively or negatively interfered with esthetic perception depending on the dentogingival alteration present. Diastema was the alteration that had the greatest negative influence. CONCLUSION: Not all dentogingival alterations interfere with esthetic evaluation. The lips are not decisive in facial attractiveness. Attraction is assessed significantly differently by laypeople than by dentists. The smile directly influences the analysis of facial beauty. CLINICAL SIGNIFICANCE: Dentogingival alterations may be imperceptible, especially when evaluating the facial joint, so its correction will not always be necessary.

Assessment of a Synthetic Type IV Cast and a Resin Polyol Used in the Fabrication of Dental Models.

OBJECTIVE: To evaluate the dimensional changes, reproduction of details, and surface roughness of a type IV cast and a resin used to fabricate dental models. MATERIALS AND METHODS: Two commercial brands of materials were evaluated: a type IV synthetic cast (Fuji Rock) and a polyol resin (Novox). Twenty samples were obtained from polyvinyl siloxane molds that reproduced the surface of a metal master model standardized according to the American National Standards Institute/American Dental Association specification no. 19. The materials were used according to the manufacturer's instructions and divided into two groups (n = 10). Each mold was photographed immediately after molding and 1 hour after molding. The obtained models were also photographed and measurements were obtained by using Image J software. The paired t-test was used to compare the molding materials and one-way analysis of variance (ANOVA) was used to compare the dimensional changes between the groups at a significance level of 5%. RESULTS: Statistically significant differences were observed between the models fabricated with the polyol resin and type IV synthetic cast with regard to reproduction of surface details, surface roughness, and dimensional stability (p < 0.05), with the resin providing superior surface detail reproduction and greater dimensional accuracy. CONCLUSION: The polyol resin exhibited superior behavior regarding detail reproduction, surface roughness, and dimensional change compared with the type IV synthetic cast.

Laypersons' Esthetic Perception of Different Dentogingival Characteristics Based on Smile Dynamics: Cross-Sectional Study.

This study aimed to evaluate laypersons' esthetic perception of different dentogingival characteristics based on smile dynamics. Six voluntary models were selected, with only one presenting dentogingival characteristics within esthetic standards: white teeth, good alignment, and adequate gingival contour. Two videos were then produced. One video focused on the mouth, whereas the other focused on the entire face of the model, to ensure that the dynamics of the smile could be evaluated. For the evaluation, 200 laypeople were asked to rank the models from first to sixth place in their order of preference. Laypeople were required to justify their reasons for choosing the first and last places. The obtained data were subjected to descriptive and inferential statistical analyses. The results showed that smile and face dynamics influenced the perception of dentogingival characteristics and facial esthetics. No significant changes were observed. However, a gummy smile accompanied by dental alterations was observed in the video of the mouth and was masked by the facial set exposed in the video of the face. A diastema between the central incisors was decisive for negative evaluation of both the mouth and face. The standard model was rated as the most pleasing. Smiles and facial dynamics influence the perception of dentogingival characteristics. Smile and facial dynamics influence the perception of dentogingival alterations among Brazilian laypeople. Diastema is an alteration that interferes with the isolated evaluation of the lower third of the face and the facial set.

Retention of cemented zirconia copings on TiBase abutments.

This study evaluated the influence of resin cements and glass ionomers on tensile strength and types of failure of zirconia copings cemented on titanium base abutments. Forty-two samples were prepared, which were formed by a Cone Morse implant, a titanium abutment with the fixing screw, and a zirconia structure made using a CAD/CAM system. The samples (n = 42) were randomly distributed according to the cementing agent: resin-modified glass ionomer cement (RelyX Luting 2), self-adhesive resin cement (RelyX U200), and self-curing resin cement (Multilink N). After cementation of the copings, half of the samples from each group (n = 7) were randomly selected and subjected to thermocycling (5000 cycles). A tensile load test was performed on a universal testing machine until failure occurred (1 mm). In addition, the type of failure was analyzed using the two-way analysis of variance test and Tukey's post-hoc test (α = 0.05). Lower tensile load was observed for the glass ionomer cement (p < 0.001) regardless of the evaluation period. After thermocycling, a significant reduction in tensile load values was verified for both evaluated cements (p = 0.047). For the resin cements, failures were predominantly of the screw fracture type (82.1%) already with the use of glass ionomer cement, and 28.5% of the failures were of an adhesive type between the zirconia coping and the cement. Resin cements have better stability under tensile load compared to resin glass ionomers when cementing zirconia copings on titanium base abutments.

Este estudo avaliou influência dos cimentos resinosos e a base de ionômero de vidro na resistência à tração e os tipos de falhas de copings de zircônia cimentados sobre pilares TiBase. Foram confeccionadas 42 amostras, sendo estas formadas por implante cone morse, pilar de titânio (TiBase) com o parafuso de fixação e uma estrutura de zircônia (coping de Zr) confeccionado através do sistema CAD/CAM. As amostras (n =42) foram aleatoriamente distribuídas de acordo com o agente de cimentação: (cimento de ionômero de vidro modificado por resina [RelyXTMLuting2]; cimento resinoso autoadesivo [RelyXTM U200] e cimento resinoso autopolimerizavel (Multilink® N). Após cimentação dos copings, metade das amostras de cada grupo (n = 7) foram aleatoriamente selecionadas e submetidas a termociclagem (5000 ciclos). O Teste de resistência a tração foi realizado em uma máquina de ensaio universal, até que ocorresse a falha (1 mm/min). Adicionalmente, o tipo de falha foi analizado. Os dados foram analisados pelo teste ANOVA two-way e post teste de Tukey's (α = 0.05). Menor média de resistência a tração foi observada para o cimento de ionômero de vidro (p < 0,001) independente do período de avaliação. Após a termociclagem, foi verificada uma redução significativa nos valores de resistênca a tração, para os cimentos avaliados (p=0,047). Para os cimentos resinosos, as falhas foram predominantemente do tipo fratura do parafuso (82,1%) já com o uso do cimento de ionômero de vidro, 28,5% das falhas foram de tipo adesiva entre o coping de Zr e o cimento. Cimentos resinosos apresentam melhor estabilidade na resistência a tração em comparação a ionmeros de vidro resinosos na cimentação de copings de zircônia sobre pilares TiBase.

Retention of cemented zirconia copings on TiBase abutments / Retenção de copings de zirconia cimentados sobre pilares tibase

ABSTRACT This study evaluated the influence of resin cements and glass ionomers on tensile strength and types of failure of zirconia copings cemented on titanium base abutments. Forty-two samples were prepared, which were formed by a Cone Morse implant, a titanium abutment with the fixing screw, and a zirconia structure made using a CAD/CAM system. The samples (n = 42) were randomly distributed according to the cementing agent: resin-modified glass ionomer cement (RelyX Luting 2), self-adhesive resin cement (RelyX U200), and self-curing resin cement (Multilink N). After cementation of the copings, half of the samples from each group (n = 7) were randomly selected and subjected to thermocycling (5000 cycles). A tensile load test was performed on a universal testing machine until failure occurred (1 mm). In addition, the type of failure was analyzed using the two-way analysis of variance test and Tukey's post-hoc test (α = 0.05). Lower tensile load was observed for the glass ionomer cement (p < 0.001) regardless of the evaluation period. After thermocycling, a significant reduction in tensile load values was verified for both evaluated cements (p = 0.047). For the resin cements, failures were predominantly of the screw fracture type (82.1%) already with the use of glass ionomer cement, and 28.5% of the failures were of an adhesive type between the zirconia coping and the cement. Resin cements have better stability under tensile load compared to resin glass ionomers when cementing zirconia copings on titanium base abutments.

RESUMO Este estudo avaliou influência dos cimentos resinosos e a base de ionômero de vidro na resistência à tração e os tipos de falhas de copings de zircônia cimentados sobre pilares TiBase. Foram confeccionadas 42 amostras, sendo estas formadas por implante cone morse, pilar de titânio (TiBase) com o parafuso de fixação e uma estrutura de zircônia (coping de Zr) confeccionado através do sistema CAD/CAM. As amostras (n =42) foram aleatoriamente distribuídas de acordo com o agente de cimentação: (cimento de ionômero de vidro modificado por resina [RelyXTMLuting2]; cimento resinoso autoadesivo [RelyXTM U200] e cimento resinoso autopolimerizavel (Multilink® N). Após cimentação dos copings, metade das amostras de cada grupo (n = 7) foram aleatoriamente selecionadas e submetidas a termociclagem (5000 ciclos). O Teste de resistência a tração foi realizado em uma máquina de ensaio universal, até que ocorresse a falha (1 mm/min). Adicionalmente, o tipo de falha foi analizado. Os dados foram analisados pelo teste ANOVA two-way e post teste de Tukey's (α = 0.05). Menor média de resistência a tração foi observada para o cimento de ionômero de vidro (p < 0,001) independente do período de avaliação. Após a termociclagem, foi verificada uma redução significativa nos valores de resistênca a tração, para os cimentos avaliados (p=0,047). Para os cimentos resinosos, as falhas foram predominantemente do tipo fratura do parafuso (82,1%) já com o uso do cimento de ionômero de vidro, 28,5% das falhas foram de tipo adesiva entre o coping de Zr e o cimento. Cimentos resinosos apresentam melhor estabilidade na resistência a tração em comparação a ionmeros de vidro resinosos na cimentação de copings de zircônia sobre pilares TiBase.