Shear bond strength of zirconia ceramic to the primary tooth dentin.

BACKGROUND: There is no information about the shear bond strengths (SBS) of zirconia ceramic to primary tooth dentin. AIM: To investigate the effect of different surface treatments and cements on the shear bond strength (SBS) of zirconia ceramic to primary tooth dentin. MATERIALS AND METHODS: Prepared zirconia bars were distributed into four groups according to surface treatment procedure: control, sandblasting, CoJet and hot etching. The zirconia specimens in each group were further divided into subgroups according to cement (n = 13): self-adhesive resin (Rely-X Unicem), resin-modified glass ionomer (Ketac-Cem Plus), and universal bioactive (BioCem). Zirconia specimens were bonded to the primary tooth dentin surface by cement. SBS was measured, and the data were subjected to two-way ANOVA and Tukey's tests. RESULTS: Statistical differences were observed in the surface treatment procedures for Rely-X Unicem (P < 0.05), but no statistically significant differences were found in the sandblasting, CoJet and hot-etching groups for Ketac-Cem Plus (P > 0.05). For BioCem, the SBS value for the hot etching group was significantly lower than those for the CoJet and sandblasting groups (P < 0.05). The SBS values for the Rely-X Unicem subgroups (sandblasting, CoJet and hot etching) were significantly higher than those for the other cements (P < 0.05). CONCLUSION: The bond strength of zirconia ceramic to primary tooth dentin is affected by surface treatments and cements.

Alteration of Exon Definition Causes Amelogenesis Imperfecta.

Amelogenesis imperfecta (AI) is a collection of genetic disorders affecting the quality and/or quantity of tooth enamel. More than 20 genes are, so far, known to be responsible for this condition. In this study, we recruited 3 Turkish families with hypomaturation AI. Whole-exome sequence analyses identified disease-causing mutations in each proband, and these mutations cosegregated with the AI phenotype in all recruited members of each family. The AI-causing mutations in family 1 were a novel AMELX mutation [NM_182680.1:c.143T>C, p.(Leu48Ser)] in the proband and a novel homozygous MMP20 mutation [NM_004771.3:c.616G>A, p.(Asp206Asn)] in the mother of the proband. Previously reported compound heterozygous MMP20 mutations [NM_004771.3:c.103A>C, p.(Arg35=) and c.389C>T, p.(Thr130Ile)] caused the AI in family 2 and family 3. Minigene splicing analyses revealed that the AMELX missense mutation increased exonic definition of exon 4 and the MMP20 synonymous mutation decreased exonic definition of exon 1. These mutations would trigger an alteration of exon usage during RNA splicing, causing the enamel malformations. These results broaden our understanding of molecular genetic pathology of tooth enamel formation.

Eruption cysts: A series of 66 cases with clinical features.

BACKGROUND: An eruption cyst (EC) is a benign, developmental cyst associated with a primary or permanent tooth. This paper presents 66 ECs in 53 patients who reported to 3 different centers in Turkey between 2014-2015. MATERIAL AND METHODS: 53 patients (31 male, 22 female) with 66 ECs were diagnosed and treated over a 1-year period. The mean age of patients was 5.4 years (minimum 5 months, maximum 11 years). Clinical examination and periapical radiographs were used to establish diagnosis. Age, gender, site, history of trauma and type of treatment were recorded. RESULTS: Of the 66 ECs diagnosed in 53 patients, more than half (56.6%) were located in the maxilla, with the maxillary first primary molars the teeth most commonly associated with ECs (30.3%). Multiple ECs were diagnosed in 13 of the 53 patients. ECs had previously diagnosed in the primary dentition of 2 patients, 3 patients reported a history of trauma to primary teeth. In the majority of patients (46 cases, 86.8%), no treatment was provided, whereas surgical treatment was provided in the remaining 7 cases (13.2%). CONCLUSIONS: Eruption cysts are usually asymptomatic and do not require treatment;. however, if the cyst is symptomatic, it should be treated with simple surgical excision.

Comparative evaluation of mineral trioxide aggregate and bioaggregate as apical barrier material in traumatized nonvital, immature teeth: A clinical pilot study.

BACKGROUND: Clinical research examining the use of mineral trioxide aggregate (MTA) as an apical barrier material are limited, and no studies have so far examined the clinical performance of BioAggregate as apical barrier material in nonvital immature teeth. AIM: This study was aimed to provide a comparative evaluation of the clinical and radiographic success of MTA and BioAggregate as an apical barrier material in children with traumatized nonvital, immature permanent maxillary incisors. SUBJECTS AND METHODS: A total of 26 maxillary incisor teeth in 20 children aged 7-11 were chosen for this study. Teeth were randomly divided into two groups according to the material to be applied, and the apical barrier was performed. Following treatment, for 24-month, teeth were clinically and radiographically evaluated once every 3- and 6-month, respectively. RESULTS: All teeth treated with MTA and BioAggregate were clinically and radiographically successful throughout the 24-month follow-up period. CONCLUSIONS: Similar success was achieved in the apical barrier that using BioAggregate and MTA. BioAggregate would be considered suitable materials for apical barrier technique and can be used as an alternative to MTA.

The effects of surface pretreatment on the microleakage of resin-modified glass-ionomer cement restorations.

OBJECTIVE: To evaluate the effect of different surface pretreatments on the marginal microleakage of Vitremer restorations. STUDY DESIGN: Class V cavities were prepared on the labial and lingual surfaces of extracted human third molar teeth. Cavities were randomly distributed into six groups according to surface treatment, as follows: Group NC (negative control): no surface treatment; Group VP (positive control): Vitremer Primer; Group PA: 32% phosphoric acid; Group PAA: 20% polyacrylic acid; Group PLP: self-etch adhesive (Prompt L Pop); Group PB: etch & rinse adhesive (Prime & Bond NT). All cavities were restored with Vitremer. Teeth were thermocycled, stained with 0.5% basic fuchsin dye and sectioned. Microleakage values were quantitatively assessed by linear measurement of dye penetration using image-analyzing software. Differences between occlusal and gingival microleakage values within groups were evaluated using paired t-tests, and differences among groups were analysed using one-way analysis of variance (ANOVA) and Tukey tests. RESULTS: There were statistically significant differences between the occlusal and gingival microleakage values for all groups (p < 0.05). Microleakage differed significantly among surface pretreatment groups (p < 0.001). The negative control and PLP groups showed similar microleakage values, but were significantly higher than other groups for both margins. Although there were no statistically significant differences between positive control and PA, PAA, PB groups, microleakage values of positive control group were smaller than all other experimental groups except for PB group. CONCLUSIONS: Vitremer restorations require surface pretreatment to prevent excessive microleakage. Pretreatment with etch & rinse adhesives and Vitremer Primer may reduce microleakage of Vitremer restorations.

Evaluation of microtensile bond strength of different fissure sealants to bovine enamel.

BACKGROUND: The aim of this study was to evaluate the microtensile bond strength (µTBS) of a new fissure sealant and compare it with conventional sealants which are applied to enamel alone, and also with self-etch and etch-and-rinse adhesives. METHODS: Enamel specimens were prepared and randomly distributed into three groups according to fissure sealant (Aegis, Helioseal F, Helioseal Clear). Each group was then subdivided according to adhesive system (Clearfil S3, Single Bond, no adhesive). A universal testing machine was used to measure µTBS, and data were analysed using one-way ANOVA and Tukey's tests. RESULTS: µTBS values for all Aegis subgroups were significantly lower than for comparable Helioseal F and Helioseal Clear subgroups (p < 0.05). No differences were observed in µTBS of Helioseal F and Helioseal Clear (p > 0.05). In the Helioseal Clear group, µTBS values for Single Bond were significantly higher than for Clearfil S3 (p < 0.05). However, no significant differences were found between the µTBS values of the adhesive subgroups in the Aegis or Helioseal F groups (p > 0.05). CONCLUSIONS: Sealant µTBS values may be affected by material content. The addition of an adhesive may improve µTBS values of sealant to enamel.