PURPOSE: The purpose of this systematic review was to examine the existing evidence on dental proportion to evaluate the existence of RED proportions in the esthetic smile in different geographic regions.
MATERIAL AND METHODS: A systematic search was conducted by reviewing different databases. The focused question was "Does RED proportion exist in esthetically pleasing smiles in different populations around the world?" The search included articles with a combination of MeSH keywords based on dental proportion from January 2000 to July 2020. The titles and abstracts were identified by using a search protocol. Full text of the articles was independently evaluated. The systematic review was modified to summarize the relevant data. The general characteristics, outcomes, and quality of studies were reviewed and analyzed systematically.
RESULTS: Seventeen studies were selected from the reviewed articles. Three studies were conducted in Europe, 10 in South Asia, and 4 in Western Asia. Eleven studies found that the mean perceived ratio of anterior teeth was not constant when progressing distally. Five studies reported that the ratio was constant in a small percentage of their populations, and 1 suggested that the ratio was constant if it remains between 60% and 80%. The central-to-LI and Ca-to-LI proportion values were not constant. Overall, the Ca-to-LI proportion values were higher than the central-to-LI proportions.
CONCLUSIONS: RED proportions were not found in the successive widths of maxillary anterior teeth among the reviewed data from different geographic regions. RED proportions are not the only standard for restoring esthetic smiles worldwide, and anterior tooth proportions differ among populations based on their race and ethnicity.
METHODS: A random sample of 800 schoolchildren aging 11-15 years was selected from different schools in the city of Dhaka, Bangladesh. The Dental Health Component (DHC) and Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) were assessed as normative treatment need. The Decayed, Missing, Filled Teeth (DMFT) index was used to record caries experience. Children were interviewed on the perception of orthodontic treatment need. Parents also completed a questionnaire on the perception of their child's orthodontic treatment need, assessed by AC/ IOTN.
RESULTS: According to the DHC/IOTN, only 24.7% were in the category of definite need (grade 4-5) for orthodontic treatment. A significant difference was found between the clinician/children and clinician/parents perceived AC score of IOTN (p= 0.0001). Multiple logistic regression showed children with a higher DMFT were significantly more likely to need orthodontic treatment, according to the DHC of IOTN.
CONCLUSION: A low proportion of schoolchildren needs normative orthodontic treatment in the city of Dhaka, Bangladesh. Children with a higher DMFT score were significantly more likely to need orthodontic treatment, according to the DHC of IOTN.
OBJECTIVES: The aim of this in vitro study was to evaluate the long-term effects of various staining solutions on the color stability of different temporary materials produced with the computer-aided design and computer-aided manufacturing (CAD/CAM) technology.
MATERIAL AND METHODS: In the study, the following materials were used: VITA CAD-Temp® (group 1); Ceramill® Temp (group 2); and Telio® CAD (group 3). Forty disk-shaped specimens (10 mm in diameter, 2 mm in thickness) of each material (N = 120) were produced with a CAD/CAM system. Staining solutions - of tea (A), of coffee (B) and cola (C) - and distilled water (D, control) were used, and color was evaluated before and after storing the samples in the solutions. Measurements were taken with a spectrophotometer and the color parameters (L*, a*, b*, and ΔE) were calculated according to the Commission internationale de l'éclairage system (CIELab). The results were evaluated with the two-way analysis of variance (ANOVA) and Tukey's tests (α = 0.05).
RESULTS: Clinically perceivable (ΔE00 > 0.8) and statistically significant (p < 0.001) color differences were detected in all specimens. The highest ΔE00 value was found in the Ceramill Temp specimens. In addition, the highest ΔE00 values were noted for the specimens stored in cola and the coffee solution for all groups. The lowest ΔE00 value was observed for the groups stored in the tea solution.
CONCLUSIONS: Clinically perceivable color changes were observed in all the specimens kept in the solutions. Color changes were greater for cola and coffee as compared to tea.
METHODS AND MATERIALS: A prospective study was conducted between April 2016 and May 2017. Twenty two adult patients aged 18-38 years with gummy smile ranging from 4 to 6 mm because of soft tissue disorders were included in the study. All patients were treated in the oral and maxillofacial department at Damascus University. The sample was divided into two groups of 11 patients. The first group was treated by the conventional standard technique, and the second group treated by a modified study technique. The amount of gingival display in full smile was evaluated in both groups following each intervention.
RESULTS: Both groups exhibited a statistically significant reduction in the measurement of gummy smile at month 1 and 6 postoperatively (P .05). The recent study showed a significant difference in gingival display between 3 and 6 months postoperatively in group 1, but no significant difference in group 2.
CONCLUSION: This study showed that the modified technique utilized in treating gummy smile has less relapse after surgery, shows excellent cosmesis and compared to the conventional technique, greater sustainability.
CLINICAL SIGNIFICANCE: The recent increase in demand for an esthetic smile has led to the development a modification of conventional lip repositioning for correcting gummy smile by myotomy of lip elevator muscles. This modified technique offers less relapse and greater stability post-operatively than the conventional technique.
AIM: To determine the incremental and total enamel loss when enamel surfaces are exposed to multiple etching cycles and to assess the relative attenuation coefficient after multiple etching cycles and resin infiltration treatment.
METHODS: Ninety extracted sound human premolars teeth were divided into 9 groups (n = 10); with each consecutive group having one additional etching cycle up to 9 cycles. The teeth were scanned with optical coherence tomography and enamel loss and attenuation coefficient were measured with MATLAB software. Enamel loss (one-way ANOVA, p ≤ 0.05) and attenuation coefficient (two-way ANOVA, p ≤ 0.05) were statistically analyzed.
RESULTS: There was a significant total enamel loss of more than 33% found at the 7th etching cycle and more. There was no statistically significant difference in the incremental mean depth of penetration of resin between various etching cycles (F(8, 134) = [2.016], one-way ANOVA, p = 0.185).
CONCLUSION: This study recommends that etching should not be repeated more than seven cycles to prevent excessive enamel loss. Following eight etching cycles, resin infiltration penetration appears approximately equal to that of healthy enamel.
METHODS: Two sets of 3-dimensional facial photographs (1 male and 1 female) each comprised 7 images that showed different dentoskeletal relations (ie, Class I, bimaxillary protrusion, bimaxillary retrusion, maxillary protrusion, maxillary retrusion, mandibular protrusion, and mandibular retrusion). The sets of photographs were shown to 101 laypersons (age, 28.87 ± 6.22 years) and 60 patients seeking orthognathic treatment (age, 27.12 ± 6.07 years). They rated their esthetic perceptions of the photographs on the basis of a 100 mm visual analog scale (VAS) from 0 (very unattractive) to 100 (very attractive).
RESULTS: The dentoskeletal Class I facial profile was ranked as the most attractive profile. Female orthognathic judges selected the retrusive maxilla while male orthognathic judges and male and female laypersons ranked the mandibular protrusion profile as the least attractive profile for both females and males. A bimaxillary protrusive female profile was viewed as more attractive by the orthognathic male (P = 0.006) and female (P = 0.006) judges, compared with female layperson judges. After adjustment for age, no statistically significant interaction between sex and judges (P >0.10) for all VAS scores were detected. For the female bimaxillary protrusive profile, orthognathic patient judges assigned a mean VAS score of 9.174 points higher than layperson judges (95% confidence interval, 3.11-15.24; P = 0.003).
CONCLUSION: Dentoskeletal Class I facial profile was generally considered the most attractive profile in both sexes; male and female orthognathic patients preferred a bimaxillary protrusive female profile. A concave facial profile was perceived as least attractive in both sexes.