Ameloplasty is counterproductive in reducing microleakage around Resin Modified Glass Ionomer and Resin based fissure sealants.

OBJECTIVE: To compare the microleakage around resin modified glass ionomer cement (RMGIC) based sealants and flowable resin based sealants placed with or without ameloplasty in extracted human teeth. METHODS: This in-vitro experimental study was conducted at the Operative Dentistry Department, Dow University of Health Sciences, Karachi, Pakistan from June 2017 to December 2018. Sixty extracted human molars and premolars were assigned to four groups (n=15) each, according to the type of fissure sealant (flowable resin based sealant or resin modified glass ionomer based sealant) used and either placed with or without ameloplasty. Specimens were thermocycled and then immersed in 1% methylene blue for 24 hours. Specimens were then sectioned and examined using stereo-microscope (50X) for microleakage that was scored on an ordinal scale. Mann-Whitney U test and Ordinal regression were applied. Level of significance kept at 0.05. RESULTS: There was a statistically significant difference (p-value <0.001) between the two sealant types for the microleakage scores. Sealants placed with ameloplasty demonstrated significantly higher microleakage values (p-value <0.001). CONCLUSION: Microleakage was found to be more pronounced in RMGIC based sealants compared to the resin based sealants. Ameloplasty resulted in higher leakage around the sealants irrespective of the chemistry of material.

Accuracy of working length measurement with endo motor having built-in apex locator and comparison with periapical radiographs.

OBJECTIVE: To determine the accuracy of working length measurement with endomotor having builtin apex locator by comparing it with periapical radiographs. METHODS: The cross-sectional study was conducted at the Department of Operative Dentistry, Dr Ishrat-ul-Ibad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, from January to June 2014, and comprised permanent maxillary anterior teeth with mature apices. A preoperative radiograph was taken by using standardised paralleling technique. The access cavity was prepared by a high speed water-cooled diamond bur. After doing initial filing and drying the canal, the working length was taken with an endomotor with built-in apex locator in dual mode using the Protaper Rotary File S1. The length was measured using a millimeter scale. After attaining tentative working length from the pre-operative radiograph, 1mm was subtracted from the radiographic apex. A stainless steel K-file was placed in the canal at this length and a radiograph was taken by paralleling technique using intraoral film holder. The electronic and radiographic findings were noted. Accuracy was considered positive if the endomotor reading was 0-2mm short of the radiographic working length. Data was analysed using SPSS 16. RESULTS: Of the 96 cases, working length with X-Smart Dual was acceptable in 85(88.5%) cases, and unacceptable in 11(11.5%) cases. CONCLUSIONS: Accuracy of working length measurement with endomotor having built-in apex locator was found to be a better measuring tool compared to the conventional periapical radiographs.

Comparison of Retrograde, Primary and Secondary Bonding Materials with Tooth Substance.

OBJECTIVE: To compare the microleakage of MTA (mineral trioxide aggregate) and resin-modified GIC (glass ionomer vitremer) as retrograde endodontic material. STUDY DESIGN: Experimental study. PLACE AND DURATION OF STUDY: Operative Department of DIIKIOHS (DUHS) and NED University, Karachi, from February to June 2014. METHODOLOGY: Forty human anterior teeth were divided into four groups. Each tooth was endodontically treated. Apical cavity preparations were performed on all teeth. The retropreparations were filled either with MTA (Group 1), Vitremer (Group 2), or only covered with nail polish (Group 3). The root surfaces of the first three groups were coated with nail polish. In Group 4 (positive control), neither retrograde filling was placed nor the nail polish was applied. The teeth were then suspended in 2% methylene blue dye solution for 10 days at 37°C. Sections were made along the long axis of teeth to determine the depth of linear dye penetration. Using Mann-Whitney test the comparison, p-value <0.05 was considered as statistically significant. RESULTS: MTA had no significant difference in apical dye leakage (p = 0.122) than did the vitremer. CONCLUSION: MTA is equivalent to vitremer in preventing microleakage when used as retrograde filling material.

An In-VitroEvaluation of Microleakage at the Cervical Margin Between two Different Class II Restorative Techniques Using Dye Penetration Method.

OBJECTIVE: To evaluate the coronal microleakage of packable composite using conventional incremental and posterior bulk fill flowable composite using Smart Dentine Replacement Single Step technique in the cervical margins of class II cavities in dentine using the dye penetration method. STUDY DESIGN: In-vitroInterventional study. PLACE AND DURATION OF STUDY: Department of Operative Dentistry, Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences (DIKIOHS), Karachi, from November 2012 to April 2013. METHODOLOGY: One hundred and twenty extracted teeth (molars and premolars) were collected and randomly divided into two experimental groups (n=60 each) and were stored in normal saline until used. Fractured samples were excluded. Standardized class II proximal box only cavities were prepared and restored with conventional methacrylate based composite using incremental technique (Group A, n=40) and low stress methacrylate resin based composite SDR using single step technique (Group B, n=40). Samples were sectioned horizontally below the cervical margins and specimen disks were prepared. The specimens were thermocycled and sealed with acid resistant varnish leaving a 1-mm interface around cervical margin and immersed in 2% methylene blue buffered solution for 24 hours. Leakage was scored 0 - 4 and measured in mm. It washed and sectioned to evaluate under stereomicroscope. RESULTS: Mean penetration was 2.4280 ±0.79 mm for Group Aand 1.015 ±0.45 mm for Group B (p < 0.001). Maximum dye penetration score for group Awas 4 and group B was 3. CONCLUSION: SDR technique in combination with total etch technique at the cervical margin of class II restorations improved the marginal seal, when were placed in dentine and thermocycled.

Effect of different tetra pack juices on microhardness of direct tooth colored-restorative materials.

PURPOSE: To examine the effect of apple and orange juices on the surface hardness of direct tooth-colored restorative materials. MATERIALS AND METHODS: The materials included resin-modified glass ionomer cement (Vitremer 3M™ ESPE™ Core buildup restorative) and composite resin (Filtek™ 3M™ ESPE™ Z350). A total of 45 disks of each restorative material were prepared. The disks were divided into groups of 15, which were immersed for 7 days in deionized water (G1/G4, control group), apple juice (G2/G5), or orange juice (G3/G6). The pH of the apple juice was approximately 4.8 and the pH of the orange juice was approximately 4.9. Surface hardness tests were performed before immersion and at various times following immersion. Statistical analysis included two-way ANOVA with repeated measurement and Tukey's test. RESULTS: Exposure to juices significantly reduced the hardness of both materials (p < 0.05), while deionized water did not affect the surface hardness of either material. The ionomer cement experienced a greater reduction than the composite resin (p = 0.000). There was no significant difference in the effect of apple and orange juices. CONCLUSION: Juice box-type fruit juices reduced the hardness of direct tooth-colored restorative materials. Material selection should be considered when planning restorations in patients who have experienced tooth surface loss. In terms of the materials evaluated in this study, the composite material provides greater durability under acidic conditions.