The aims of this study were to measure the distribution, prevalence and the severity of malocclusion and treatment need amongst randomly selected (n = 703) rural and urban Nigerian children aged 12-18 years (mean 14.0 +/- 1.84) using the dental aesthetic index (DAI), and to assess whether malocclusion was affected by age, gender and socio-economic background. Data were collected according to the method recommended by WHO. Most of the children (77.4 per cent) had a dental appearance which required no orthodontic treatment. Over 13 per cent fell into the group where treatment for malocclusion is considered to be 'elective'. However, a substantial proportion (9.2 per cent) of the population had severe to handicapping malocclusion where treatment is 'highly desirable' or 'mandatory'. There were no statistically significant differences (P > 0.05) in DAI scores between age groups, gender and socio-economic background. This study also found that Nigerian adolescents had better dental appearance and less orthodontic treatment need compared with the Caucasian and Oriental populations.

The standard dental aesthetic index (DAI) is an orthodontic treatment need index based on perceptions of dental aesthetics in the United States. It is a regression equation that links perceptions of the social acceptability of dental aesthetics with the objective intraoral measurements of ten occlusal traits. For the index to be universally acceptable, the perceptions of dental aesthetics in other countries must be similar to those of the United States. This study was designed to determine whether the perceptions of dental aesthetics of Nigerian students are similar to those of different groups of the US population. The same 25 stimuli (photographs of dental configurations, a subset of the 200 stimuli used in deriving the standard DAI equation) were rated for dental aesthetics by Nigerian students. Their ratings were compared with ratings of the same 25 stimuli by US parents, students and orthodontists. Spearman rank-order correlations ranged from 0.75 to 0.84. These correlations were highly significant (P<0.0001), and showed that the perceptions of dental aesthetics of Nigerian students were very similar to those of the US groups. The study therefore concluded that standard DAI could be used as a screening tool and without modification in epidemiological surveys among Nigerians.

The purpose of this study was to investigate the pattern of toothwear in the permanent teeth of 12-18-year-old Nigerian students. The study group comprised 176 individuals (67 males and 109 females) who had no carious cavity, restoration or fracture on any of their permanent teeth. Within the group, 86% had tooth surface loss that was limited to enamel and dentine. No statistically significant differences were observed between the sexes. The most commonly affected tooth was the lower first molar, while the occlusal surface was the most frequently involved. One student had toothwear with a predominantly erosive component as a result of frequent ingestion of low pH drinks, while another displayed toothbrush abrasion. Of those with toothwear, two (13.4%) had parafunctional activities. The cause of toothwear in 73.2% of the study population could not be ascertained. Some of it may be connected with the coarse, abrasive diets that many of the students admitted to consuming on a regular basis.

The purpose of this study was to test in shear mode the bond strengths of two BIS-GMA resin cements bonded to alumina blasted and heat-treated gold alloy surfaces. This was carried out in order to investigate the manufacturer's claim of the superiority of Panavia 21 over Panavia Ex. Alumina blasted gold alloy surfaces were cemented in pairs with either Panavia Ex or Panavia 21 resin cements. Heat-treated gold alloy surfaces were similarly paired. The luted pairs were stored in water at 37 degrees C for 48 h before bond was tested with shearing forces. Although the differences were not statistically significant, it was found that Panavia 21 formed stronger bonds on the alumina blasted surfaces than Panavia Ex. However, Panavia Ex exhibited higher mean strength values than Panavia 21 on the heat-treated surfaces. Not only was this difference statistically significant, but the bond strength values obtained for Panavia Ex on this surface were the highest in the data set. On the basis of bond testing in shear, it would appear that Panavia 21 is inferior to Panavia Ex on heat-treated gold alloy surfaces.

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