مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال بیست و دوم شماره 3 (پیاپی 60، پاییز 1388)

Evaluation of shear bond strength and microleakage of bonding agents is important as these properties play main roles in adhesion of composite to dental tissues. Microleakage results in bacterial penetration into dentin tubules and enamel surfaces and causes sensitivity and recurrent caries followed by destruction of composite filling. Insufficient shear bond strength results in early failure of filling in low masticatory forces. The main goal of this study was to compare the microleakage and shear bond strength of an experimental adhesive and Scotchbond multi-purpose (MP) adhesive system.

In this experimental study, sixty extracted caries free human molar teeth were randomly assigned into 4 groups of 15 each for shear bond strength. Variables were bonding agents, enamel and dentin. Twenty teeth assigned into 2 groups of 10 each were used for valuation of the microleakage. Microleakage and shear bond strength were performed according to ISO TR 11405. All data were analyzed with parametric and non-parametric tests according to their normality distribution. Also, Weibull distribution performed on data.

Data obtained from both microleakage and shear bond strength tests showed no significant difference between the experimental bonding and Scotchbond MP bonding (P>0.05). Furthermore, there was no significant difference between the microleakage of occlusal and gingival parts of both bondings (P>0.05).

Experimental adhesive bonding showed acceptable results regarding microleakage and shear bond strength. It may be concluded that the experimental dentin bonding had a comparable performance quality with that of commercial system.

The usage of free gingival grafts for vestibuloplasty is a routine procedure. The free gingival procedure requires harvesting the graft from a donor site which increases morbidity and the risk of surgical complications. In addition, adequate amount of donor tissue may not be available. Acceptable results of Alloderm application as a substitute for autogenous soft tissue grafts are: Not exposing the patient to an additional surgery, no donor site morbidity, unlimited availability, decreasing the bleeding during the surgery, decreasing the surgical complications, and better color match. The aim of this study was to evaluate the maintenance of the vestibular depth in vestibuloplasty with mucosal graft and Alloderm.

Both methods of anterior mandibular vestibuloplasty by Clark, utilizing Alloderm and mucosal grafts, were employed in ten clinical cases. During the surgeries, half the prepared recipient sites received Alloderm, while the remaining half received autografts in a randomized fashion. Immediately, 1, 3, and 6 months postoperatively, the variables of graft rejection, depth of vestibule and the degree of relapse were evaluated. SPSS software was used for analysis of the data and the methods used for "statistical tests" were as follows: Friedman Method, Paired sample t-test, Smirnov-kolmogrove Method. (The statistical significance level was established at P-value<0.05.

The mean difference of the relapse measurements in both methods throughout the survey did not have significant predictive value (P>0.05). Similar results were achieved for the mean difference of depth of the vestibule.

In patients undergoing Vestibuloplasty, Alloderm could be material of choice to be utilized as autogenic soft tissue grafts in pre-prosthesis procedures.