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Purpose: The purpose of this study was to compare five different abutment-crown combinations for single implant-supported restorations regarding their capabilities to withstand loads., Materials and Methods: Fifty implants were placed into resin blocks, and the restorations were connected to the implants. The five tested restorations were: (1) metal-ceramic crowns cemented to titanium abutments, (2) In-Ceram crowns cemented to titanium abutments, (3) Celay feldspathic crowns cemented to titanium abutments, (4) In-Ceram crowns cemented to milled ceramic abutments, and (5) Celay feldspathic crowns cemented to milled ceramic abutments. The specimens were loaded at 0- and 45-degree angles to the long axis, and the load values at the moment of failure were recorded using a universal testing machine., Results: The fracture strengths under vertical loading were greater than those under oblique loading. The fracture strengths of metal-ceramic crowns cemented to the titanium abutments were higher than those of all-ceramic crowns cemented on the milled ceramic abutments, regardless of loading direction. There were no differences in the fracture strengths of the ceramic crowns between the two different abutment types under oblique loading., Conclusion: All-ceramic crowns on the milled ceramic abutments were weaker than the metal-ceramic crowns on the titanium abutments under oblique loading.

Purpose: This article reviews recent research on the esthetics of the smile, covering the attractiveness of the smile, the effect of aging on the smile, oral condition and the smile, personality and smile, and smile exercises., Material and Methods: The subjects were Koreans with normal occlusion. Photographs of a full smile were taken and the esthetic quality of the subjects' smiles was estimated. Smile scores were correlated with oral condition, personality, the practice of smile exercises, and elements of the smile, such as the position of the lip in a smile. The personality of the subjects was assessed by means of a Sixteen Personality Factor Questionnaire. Gibson's smile exercises were used to investigate the effect of smile exercise., Results: In an attractive smile, the full shape of the maxillary anterior teeth was shown between the upper and lower lip, the upper lip curved upward or was straight, the maxillary anterior incisal curve was parallel to the lower lip, and teeth were displayed to the first molar. The amount of maxillary incisal exposure gradually decreased with age, accompanied by a gradual increase in mandibular incisal exposure. Personality traits such as warmth, calmness, extroversion, and low anxiety were closely related to an attractive smile. Smile exercises were an effective means of improving the esthetic level of the smile if patients exercised continuously., Conclusion: An attractive smile is important for esthetic treatment. The lip position, oral condition, personality traits, and smile exercise affect the esthetics of the smile.