Journal of Orthodontics

The aim of this study was to develop a reliable and valid Nepali version of the Psychosocial Impact of Dental Aesthetic Questionnaire (PIDAQ).

Cross-sectional descriptive validation study.

B.P. Koirala Institute of Health Sciences, Dharan, Nepal.

A rigorous translation process including conceptual and semantic evaluation, translation, back translation and pre-testing was carried out. Two hundred and fifty-two undergraduates, including equal numbers of males and females with an age ranging from 18 to 29 years (mean age: 22·33±2·114 years), participated in this study. Reliability was assessed by Cronbach's alpha coefficient and the coefficient of correlation was used to assess correlation between items and test–retest reliability. The construct validity was tested by factorial analysis. Convergent construct validity was tested by comparison of PIDAQ scores with the aesthetic component of the index of orthodontic treatment needs (IOTN-AC) and perception of occlusion scale (POS), respectively. Discriminant construct validity was assessed by differences in score for those who demand treatment and those who did not.

The response rate was 100%. One hundred and twenty-three individuals had a demand for orthodontic treatment. The Nepali PIDAQ had excellent reliability with Cronbach's alpha of 0·945, corrected item correlation between 0·525 and 0·790 and overall test–retest reliability of 0·978. The construct validity was good with formation of a new sub-domain ‘Dental self-consciousness’. The scale had good correlation with IOTN-AC and POS fulfilling convergent construct validity. The discriminant construct validity was proved by significant differences in scores for subjects with demand and without demand for treatment.

To conclude, Nepali version of PIDAQ has good psychometric properties and can be used effectively in this population group for further research.

To compare the accuracy of cone-beam CT (CBCT) with conventional horizontal and vertical parallax for the localization of ectopic maxillary canines.

Observational study.

A typodont was constructed using human teeth embedded in radio-dense impression material, containing a simulated ectopic canine. Image sets (vertical/horizontal parallax and CBCT scans) were obtained for nine positions. A photograph confirmed the true position of the canine. Six observers used horizontal (HP) and vertical (VP) parallax techniques with conventional radiographs and the axial, coronal and sagittal CBCT views to locate the canine tip. Images were manipulated as required using proprietary software (http://www.carestream.com and http://www.i-cat.com). Intra-observer reproducibility was calculated by one observer re-evaluating the image sets after 2 months. Individual observer validity was calculated in relation to the photographic position of the canine using weighted Kappa. Differences in the proportion of correct locations between CBCT and vertical/horizontal parallax were tested using McNemar tests (P<0·05).

Intra- and inter-observer agreements were excellent (0·8985) and substantial (0·7528), respectively. Individual observer validity was substantial-excellent (0·7368–0·900). The canine position was correctly identified in 94% of cases located using CBCT, 83% using HP and 65% using VP. The differences between CBCT and vertical and horizontal parallax were highly statistically significant (P<0·01).

CBCT is more accurate than either horizontal or vertical parallax for the localization of ectopic maxillary canine teeth.

This study aimed to compare facial morphologies of an adult African-American population to an adult Caucasian-American population using three-dimensional (3D) surface imaging.

The images were captured using a stereophotogrammetric system (3dMDface^TM system). Subjects were aged 19–30 years, with normal body mass index and no gross craniofacial anomalies. Images were aligned and combined using RF6 Plus Pack 2 software to produce a male and female facial average for each population. The averages were superimposed and the differences were assessed.

The most distinct differences were in the forehead, alar base and perioricular regions. The average difference between African-American and Caucasian-American females was 1·18±0·98 mm. The African-American females had a broader face, wider alar base and more protrusive lips. The Caucasian-American females had a more prominent chin, malar region and lower forehead. The average difference between African-American and Caucasian-American males was 1·11±1·04 mm. The African-American males had a more prominent upper forehead and periocular region, wider alar base and more protrusive lips. No notable difference occurred between chin points of the two male populations.

Average faces were created from 3D photographs, and the facial morphological differences between populations and genders were compared. African-American males had a more prominent upper forehead and periocular region, wider alar base and more protrusive lips. Caucasian-American males showed a more prominent nasal tip and malar area. African-American females had broader face, wider alar base and more protrusive lips. Caucasian-American females showed a more prominent chin point, malar region and lower forehead.

This investigation aimed to assess and compare the amount of residual monomer (RM) released from removable orthodontic appliances constructed by sprinkle-on and dough techniques.

One hundred and twenty acrylic samples were prepared from orthodontic autopolymerized acrylic resins and divided into three groups, according to the processing method: sprinkle-on with polyclave, sprinkle-on without polyclave and dough technique. After polymerization, the specimens of each group were immersed in distilled water for 24 h, 48 h, 72 h and 1 week. High-performances liquid chromatography (HPLC) was utilized to measure residual monomer content.

Maximum observed RM was 1284·91±129·07 ppm measured for sprinkle-on technique without polyclave after 24 h of water immersion. At this time, the level of RM was significantly different among the three applied techniques (P<0·05). In all soaking time groups, sprinkle-on technique with polyclave released the least amount of RM. Within each group, the maximum monomer releasing was observed after the first 24 h and decreases were observed in subsequent time groups. The reduction over the time was not significant in the polyclave groups (P>0·05).

The sprinkle-on technique with polyclave and longer water immersion reduced residual monomer released from acrylic orthodontic appliances.