No abstract

IntrOductIOnDirect composite restorations are gaining an increased popularity over the conventional amalgam restorations due to esthetic demands and concerns regarding mercury in amalgam [1]. The clinical success of the composite restorations is very much dependent on its polymerization and degree of conversion. Highly viscous composites are very hard to adapt accurately to cavity preparations and may leave behind unwanted voids, hence, more flowable composites with less filler content were introduced. There are many factors which affect the viscosity of resin.One of the greatest limitations of direct resin composite restoration is linked to its high polymerization shrinkage. During polymerization, it changes from a pre gel phase to a post gel phase. During the pregel stage, the reactive species can rearrange themselves without generating much internal and interfacial stresses to compensate for any volumetric shrinkage [2][3][4]. However, in the post gel stage the resin has partially set and can no longer undergo plastic deformation to compensate for any volumetric shrinkage. As a result, tensile stresses are generated at the resin tooth interface and causes pulling of the material away from the tooth surfaces [5,6]. C-factor, also known as configuration factor is the ratio of unbonded to bonded surface which affects the polymerization shrinkage of the restoration. During polymerization of resin composite, any volumetric shrinkage will be compensated by rearrangement or flow of the resin composite. Only free surfaces of a restoration are able to act as a reservoir for plastic deformation in the pre gel stage. Thus, if clinically the C-factor can be decreased, the polymerization shrinkage may be decreased as well.Composites with less viscous consistency were introduced because it increases adaptation and decreases micro-leakage along the restoration tooth interface. Many attempts have been made including incorporating flowable composites, fiber inserts, or chemical and laser treatments of dentin [7][8][9][10][11][12][13]. Chairside warming of composite resins before photopolymerisation is seen to reduce viscosity and increase flowability by increasing the degree of conversion. When temperature increases, both the radical and monomer mobility increases resulting in a more highly cross-linked polymer network [14]. With this increase in conversion, mechanical and physical properties of the resin are also increased. Also, preheated composites have a better surface hardness and greater depth of cure [15,16]. A study by Bortolotto and Krejci showed that when temperature was raised from 5°C to 40°C, there is a significant increase in the Vickers Hardness at a curing depth of 0.5mm [17]. AImThe aim of the study is to determine the effect of temperature on the degree of micro leakage in resin composite restorations. mAtErIALS And mEtHOdSThe study was conducted in Saveetha Dental College, Chennai, India and was approved by the Scientific Review Board Committee. A total of 60 extracted non carious premolars, previously stor...

The inferior alveolar nerve (IAN) block is the most frequently used mandibular injection technique for achieving local anesthesia for dental treatment. However, the IAN block does not always result in successful anesthesia. Various other nerve blocks were introduced over the period of time to improve the success rate of anesthesia. The objective of this systematic review was to compare and evaluate the anesthetic efficacy of Inferior alveolar nerve block with various mandibular nerve blocks in dental patients. Electronicdatabases were systematically searched for randomized controlled clinical studies and Clinical trials studies. Studies were selected by predefined inclusion criteria. Methodological quality was appraised and strength of evidence was determined. Seven studies from seven countries were included based on inclusion criteria. Although there is difference in the values comparing the different techniques the data is not significantly different in the anesthetic efficacy of various mandibular nerve block in dental patients. Based on this review, most of the articles included, point towards a better anesthetic efficacy of the classic inferior alveolar nerve block compared to the other inferior alveolar anesthesia techniques. However due to various variables like type of local anesthesia, experience of the operator and familiarity with the individual techniques it is not possible to conclude that classic inferior alveolar nerve block is relatively superior. Hence further research should be aimed at better matching of groups and variables like operator experience and familiarity to validate the findings.

No abstract

No abstract