Objective: To determine the prevalence and distribution of premature eruption and agenesis of premolars in a sample of Turkish children. Study design: A sample of 1715 patients aged 5 to 11 years was selected. Panoramic radiographs were used to assess premature eruption and agenesis of premolars. Developmental stage of erupted premolars was assessed using Demirjian’s method and selecting prematurely erupted premolars on the basis of clinical eruption with a root length less than half of their final expected root lengths. Statistical analysis was performed using chi-square test (p <.05). Results: One hundred fifteen (6.7%) of 1715 patients presented at least one premolar agenesis with no significant sex difference (56 boys, 59 girls). Mandibular second premolars were the most absent teeth. Multiple agenesis of premolars (3.4%) was more common than single agenesis (3.3%). A total of 85 (5.0%) patients (51 boys, 34 girls; no significant sex difference) had at least one prematurely erupted premolar, and maxillary first premolars were most commonly affected. Early erupted premolars were in stage D or E based on Demirjian’s dental formation scale. Conclusions: The prevalence of premature eruption and agenesis of premolars in Turkish children were 5.0% and 6.7%, respectively. Both conditions are not uncommon and may highlight the need for early diagnosis to prevent subsequent clinical problems.

Objective: This study investigated the effect of ozone pretreatment on the microleakage and marginal integrity of pit and fissure sealants placed with or without a self-etch 6th generation adhesive. Study Design: Freshly-extracted, human third molars were randomly assigned into two main groups (n=48):Group A: Fissures were pretreated with ozone; Group B: Fissures were left untreated. The teeth were further randomly divided into two subgroups (n=24/each) so that half of teeth were sealed with a conventional fissure sealant (Fissurit F, Voco, Germany), while the remaining half received the same sealant bonded with a self-etch adhesive (Clearfil Protect Bond, Kuraray, Japan). Following thermal cycling (1000X), the specimens were subjected to dye penetration within 0.5% basic fuchsin for 24h. The extent of dye penetration was measured by image analysis. Kruskal Wallis and Mann-Whitney U tests were used for statistical analysis of the data (p=0.05). Two randomly-selected sections from each group were observed under SEM. Results: In all groups, ozone pretreatment significantly reduced the extent of microleakage (p<0.001). SEM investigation demonstrated better adaptation of the sealants in ozone-pretreated groups. Clearfil Protect Bond did not improve the marginal seal of Fissurit F (p>0.05). Conclusion: Ozone pretreatment favorably affected the marginal sealing ability of the tested fissure sealants.