Objective:The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth.Methods:Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the “H” mode, following parameters of cavity preparation – power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters – power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens).Results:Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018).Conclusion:Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

BACKGROUND:The success of implants is associated first with their osseointegration, and later on with their survival rate. In recent years, many efforts have been exerted to develop implant design, geometry, materials and techniques to enhance the osseointegration process and also to increase the success rate of implant procedures. New techniques, like leukocyte and platelet-rich fibrin (L-PRF) and low-level laser treatment (LLLT), have been developed to enhance the osseointegration around dental implants.AIM:This study aims at accelerating bone osseointegration process around dental implant using new techniques to increase the success rate, to allow immediate or early loading of a dental implant, and to make a comparison between the various new techniques in dental implant procedures to figure out which technique will achieve the best results.METHODS:The study was conducted on a random sample of 40 male patients. Dental implants were placed in the posterior areas of the lower jaw. Patients were divided randomly into 4 groups; control group, LLLT group, L-PRF group and L-PRF plus LLLT group. They were assessed using cone-beam computed tomography (CBCT).RESULTS:The results showed significant differences between all groups over different measured times. All the groups showed improvement in comparison with Normal group, where L-PRF group showed the best result followed by (L-PRF+LLLT) group, while the LLLT group showed the least improvement in comparison with bothL-PRF group and (L-PRF+LLLT) group.CONCLUSION:The study demonstrates that L-PRF gives a better performance in the osseointegration around dental implants than LLLT.

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The most common method for the removal of all-ceramic restorations is to use a highspeed handpiece with a stone or bur. Unfortunately, this process can be difficult, time-consuming and may lead to the loss of healthy tooth structures. Lasers have been suggested and used to remove ceramic orthodontic brackets, laminate veneers and full anatomical crowns.Aim: Aim of the present study was to evaluate the debonding effect of erbium, chromium-doped yttrium, scandium, gallium and garnet (ErCr:YSGG) on Computer-aided design and computer-aided manufacturing (CAD/CAM) end crown restorations. Materials and methods:Overall, 30 molar samples were prepared for this study and divided into two groups as follows:Group A-(n = 15): Endocrowns subjected to ErCr:YSGG laser application.Group B-(n = 15): Endocrowns not subjected to the laser (control). Endocrowns were fabricated from lithium disilicate ceramics and manufactured using a CAD/CAM machine. Cementation was done using Bisco Duo Link Universal™ resin cement. ErCr:YSGG laser was used with wavelength 2780 nm, 0.3J energy, 10 Hz frequency and 1000 µm tip size. Pull out test was done using a universal testing machine. Results:It was found that Non-laser group recorded statistically significant (p < 0.05) higher mean value (258.14 ± 63.43 N) for debonding than Laser group mean value (156.66 ± 32.89 N) as indicated by student t-test. Additionally, no carbonization at the dentin/cement interface was observed. Conclusion:According to the results of this study, ErCr: YSGG application can be considered a conservative method for the debonding of all ceramic endocrowns.Clinical significance: Some practitioners have been against the use of endocrown restorations due to the difficulty faced in removal and retrieval, the use of laser is an alternative, effective and conservative method.

The aim of this study was to compare and contrast the influence of low-level laser therapy (LLLT) on the osseointegration of delayed and delayed-immediate dental implants. Forty implants were installed in the maxillary premolar regions of forty male subjects of age ranged 40-45 years old. Subjects were then randomly divided into four groups (I, II, III, and IV), delayed implant control group, delayed implant laser group, delayed-immediate implant control group, and delayedimmediate implant control group. Following implant insertion, the healing phase of groups (I and III) was left to progress spontaneously. Groups (II and IV) were subjected to low intensity (gallium arsenide diode) laser application with wavelength of 904 nm, an output power of 30 mWatts, and a frequency of 9999 Hz for 3 minutes in three sessions on three alternative days starting from the tenth post-operative day. A six month follow up period was applied radiographically to all subjects of both groups using sequential conventional radiographs. Radiographs were digitized by a professional scanner and bone density was recorded. The results revealed that low intensity laser therapy (LLLT) provided an easy as well as efficient method for accelerating bone healing and improving osseointegration whatever the technique used for implant insertion. The study concluded that laser could be used as additional aid for improving osseointgration and increasing the success rate for implantation protocols.

This study was carried out to evaluate the effect of acid etching versus laser etching of dentin surface on the bonding of Composite and Compomer restorative materials to dentin surface by studying microleakage at the dentin-filling interface, compositional analysis of dentin surface, and Scanning Electron Microscopic (SEM) study of the bonding area. 120 freshly extracted premolar teeth were divided according to surface treatment into three groups. Group I (Acid etching group) contained thirty teeth. Twenty teeth were selected to assess microleakage by forming standardized class V cavity on the buccal surface of the selected teeth. Then, teeth were subdivided into two subgroups with 10 teeth in each. Subgroup (i) delivered composite filling while subgroup (ii) delivered compomer filling according to manufacturer instructions. microleakage at the dentinfilling interface of teeth was examined using dye penetration method. dye penetration scores at occlusal and gingival margins were recorded and tabulated. Five dentin surfaces of five teeth from group I were etched by acid then prepared for compositional analysis of dentin surface by Infra-Red (IR) Spectroscopy. Another Five dentin surfaces were etched by acid then prepared for (SEM) assessment. Group II (Laser etching group) contained ninety teeth, twenty teeth were used for assessing microleakage after laser etching taking similar steps to that of acid etching. Thirty dentin surfaces of thirty teeth were etched by laser with different parameters then prepared for compositional analysis of dentin surface by IR Spectroscopy. Thirty dentin surfaces of thirty teeth were etched by laser with different parameters then prepared for SEM assessment. Group III (Untreated group) contained ten teeth that were left untreated. Five dentin surfaces of five teeth were subjected to IR Spectroscopy assessment. Five dentin surfaces of five teeth were prepared for SEM assessment. The results revealed that acid etching of dentin surface resulted in significant less leakage compared to laser etching. IR Spectroscopy revealed changes in dentin surface structure indicating that there was a reaction occurred by the acid and laser etching. SEM assessment showed more openings of dentinal tubules in case of acid etching, while in case of laser etching, there were a surface structural changes with a melting and fusion dentin surface. Acid etching of dentin gives better results on the bonding of Composite and Compomer filling materials than laser etching and thus gives more successful clinical condition. Further investigations are needed by using different types of laser to get more benefit from applications of laser clinically.

AIM: This in vitro study was designed to evaluate the shear bond strength after bonding between porcelain laminate veneers and the tooth surface using different etching methods METHODS: Thirty freshly extracted maxillary premolars were used and prepared for receiving Enamic laminate veneers. Specimens were divided into two groups (n = 15), according to the surface treatment protocol. The specimens were sandblasted with 50 μm Al2O3 for 20 s; 2 bar pressure was maintained for air abrasion. Distribution of groups was as follow G1: Prepared enamel surface treatment of each tooth was according to the manufacturer’s instructions. G2: The prepared enamel surface of each tooth was subjected to Erbium,Chromium-Doped: Yttrium, Scandium, Gallium, and Garnet laser application. Light cured adhesive resin cement was applied to fitting surface of each ceramic specimen. To simulate thermal aging, the samples were subjected to 5000 thermal cycling in a thermocycler. By dividing the failure load (N) by the bonding area (mm2), debonding loads were calculated as shear stress (MPa). Numerical data were presented as mean and standard deviation values. They were explored for normality by checking the data distribution using Shapiro–Wilk test. Data showed parametric distribution and were analyzed using independent t-test. The significance level was set at p ≤ 0.05 within all tests. Statistical analysis was performed with R statistical analysis software version 4.1.2 for Windows. RESULTS: Group (II) (15.84 ± 3.09) had significantly higher mean value than group (I) (13.69 ± 2.36) (t = 2.15, p = 0.041). CONCLUSION: Within the limitation of this study, it was revealed that the laser surface treatment for tooth substrate plays a significant role in increasing the shear bond strength of laminate veneers.