ABSTRACT
BACKGROUND: The rapid progress of adhesive dentistry over the past decade has been attributed to the significant advances in dentin bonding technology. Requirements of an ideal bonding agent are quite similar to those indicated by Buonocore despite of many improvements. As we enter the new millennium, it is important for us to examine the past. OBJECTIVE: To evaluate the microleakage of three bonding agents namely Single Bond, Prime & Bond NT and Excite using different composite materials namely Z100, Spectrum TPH, Tetric with three different placement techniques. MATERIALS AND METHODS: Fifty four extracted human premolars were taken & divided into 9 groups depending upon application of bonding agents followed by composite restorations. Specimens were subjected to thermal cycling at 6(0)C, 37(0)C, 54(0)C and again at 37(0)C & then placed in 10 ml each of freshly prepared 50% silver nitrate solution for 2 hour in darkness, washed & placed under sun light for 24 hours. The sectioned specimens were then observed under stereomicroscope to detect microleakage. RESULTS: On comparing the mean microleakage scores among the three groups, maximum microleakage scores have been obtained when no bonding agent was used, while least microleakage scores were obtained with double coat of bonding agent. CONCLUSION: The present study suggests that the placement of bonding agent technique before composite restoration can be effective to limit the microleakage at the tooth restoration interface.
ABSTRACT
INTRODUCTION: Posterior transverse discrepancy as seen in some cases of Class II Division 1 malocclusion in mixed dentition period can be related to typical skeletofacial characteristics. These features when studied early in the mixed dentition period give a clear view of the desired appropriate treatment plan in a particular case. AIM: The purpose of this study was to establish a simple method to determine the posterior (intermolar) transverse discrepancy and craniofacial skeletal features between the dental arches during the mixed dentition in a sample of Class II Division 1 patients to provide diagnostic and therapeutic guidance in the early approach. MATERIALS AND METHODS: A sample of 60 Class II Division 1 patients in mixed dention that were divided into 30 Class II Division 1 patients with posterior transverse interarch discrepancy {Class II (I) PTID group} and 30 Class II Division 1 patients without posterior transverse interarch discrepancy {Class II (I) NPTID group}. Thirty Class I subjects in mixed dentition were included as control. RESULTS: The skeletal features of the Class II group without PTID are those of the skeletal Class II associated with 'anatomic' mandibular retrusion (due to a micrognathic mandible) and those of the Class II group with PTID as skeletal Class II associated with only a 'functional' mandibular retrusion (due to a posteriorly displaced mandible of normal size). CONCLUSION: This study confirmed the role of occlusion in the control of maxillomandibular skeletal relationships.The treatment strategies could be planned on the basis of the transverse component of Class II Division 1 groups in the mixed dentition period.
