Efficacy of using erbium, chromium-doped: Yttrium scandium gallium garnet laser-treated dentine in a dentine barrier test device.

OBJECTIVES: The aim of this study was to evaluate the efficacy of using erbium, chromium-doped:yttrium scandium gallium garnet (Er,Cr:YSGG) laser-treated dentine in a dentine barrier test device. MATERIALS AND METHODS: The test materials (G-Bond™ and Vitrebond™) were applied onto laser-treated or laser-untreated dentine discs. After 24 h of exposure with perfusion of the test chamber, cell survival was evaluated based on enzyme activity and compared to a nontoxic control material. The mean of the control was set to 100% viability. Data were analyzed using the one-way analysis of variance and the Tukey's honest significant difference tests. RESULTS: The responses of bovine pulp-derived cells after exposure to G-Bond and Vitrebond on Er,Cr:YSGG laser-treated and laser-untreated dentin were statistically different from negative control group (P < 0.05). CONCLUSION: Er,Cr:YSGG laser treatment was not successful enough in decreasing the cytotoxic effects of the dental materials. Different parameters of Er,Cr:YSGG laser or different laser types could be investigated as an alternative to minimizing the cytotoxic effects of dental materials.

Evaluation of Teeth Development in Unilateral Cleft Lip and Palate Patients in Mixed Dentition by Using Medical Image Control Systems.

OBJECTIVES: The aim of this study was to evaluate the crown and root development in patients with cleft lip and palate using medical software programmes. MATERIALS AND METHODS: In our study, 25 patients with mixed dentition unilateral cleft lip and palate were examined with cone-beam computed tomography (CBCT). The tomography images obtained as high resolution medical images on the computer control system (MIMICS 15.0, Materialise, Leuven, Belgium and SOLIDWORKS 2014 Premium, Concord, Massachusetts) were converted to three-dimensional volumetric images. These three-dimensional images of the cleft on the sides of the teeth in the crown and root growth were measured by mesiodistal length and crown/root rate with volume and area. These measurements were compared with a control group of healthy individuals. RESULTS: There were no statistically significant differences in the volume, surface area and MD size, crown/root ratio of central incisor, canine, first premolar and second premolar teeth within defect, and healthy teeth. However, it was found that there was a significant difference between the volume, surface area and MD size, and crown/root ratio of the lateral teeth in each group. CONCLUSION: In particular, among patients with cleft lip and palate, on obtaining a solid model of the tooth structure by using these programs, tooth development can be examined in more detail, diagnosis can be made more reliable, as well as in treatment planning. We believe that these programs can be used to resolve certain limitations such as a lack of an application to be used in routine dental treatment and in particular the need to do more study.

Effect of different modes of erbium:yttrium aluminum garnet laser on shear bond strength to dentin.

OBJECTIVES: The aim of this study was to evaluate the effect of different surface treatments on the shear bond strength (SBS) of resin composites to dentin using total etch dentin bonding adhesives. MATERIALS AND METHODS: Sixty extracted human molars were flattened to obtain dentin surfaces. The samples were divided into three groups (n = 20): Group I: 37% phosphoric acid + optibond FL + resin composite; Group II: Erbium:yttrium aluminum garnet (Er:YAG) laser (medium short pulse [MSP] mode, 120 mJ/10 Hz) + optibond FL + resin composite; Group III: Er:YAG laser (quantum square pulse [QSP] mode, 120 mJ/10 Hz) + optibond FL + resin composite. After the specimens were prepared, the SBS test was performed at a crosshead speed of 0.5 mm/min. The fractured specimens were examined under a stereomicroscope to evaluate the fracture pattern. Statistical analyses were performed with one-way ANOVA and Tukey's honestly significant difference tests. One sample of treated dentin surface from each group was sputter-coated with gold, and scanning electron microscope (SEM) images were captured. RESULTS: Acid etching showed significantly higher SBS than the other groups (P < 0.05). However, the difference between Er:YAG MSP and QSP mode groups was not statistically significant (P > 0.05). SEM images of the acid-etched dentin surface showed opened dentinal tubule with a regular surface, but Er:YAG MSP mode treated surface was irregular. The surface treated with Er:YAG QSP mode represented wide dentinal tubules with a clean and flat surface. CONCLUSION: Using different modes (MSP and QSP) of Er:YAG laser for dentin surface treatment before application of total etch adhesives is still not an sufficient alternative compared to acid etching.

Fluoride release/recharging ability and bond strength of glass ionomer cements to sound and caries-affected dentin.

OBJECTIVES: The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS) of different glass ionomer cements (GICs) on sound/caries-affected dentin and to assess the fluoride release/recharging ability. METHODS: After creating artificial caries lesions, teeth with sound and caries-affected dentin were assigned to be restored with one of the GICs: Ketac N100; GC Equia; GCP Glass Fill, and tested using a microtensile test. Ten of each material were prepared, and fluoride ion-release was measured at 10 different intervals. After 1.23% acidulated phosphate fluoride-gel immersion, fluoride re-release was then measured at the same intervals. RESULTS: In sound dentin, GC Equia exhibited significantly higher µTBS value (P < 0.05). The mean µTBS of Ketac N100 to caries-affected dentin was significantly lower than the other materials (P < 0.05). All materials showed maximal fluoride release at 24 h, GC Equia released the most fluoride. CONCLUSION: The bond strength of GICs is affected by tooth substrate. High-viscosity GICs show higher initial fluoride release as well as greater fluoride recharge capacity.

Cytotoxicity evaluation of dentin contacting materials with dentin barrier test device using erbium-doped yttrium, aluminum, and garnet laser-treated dentin.

OBJECTIVES: The effect of dentin contacting materials on three-dimensional cultures of pulp-derived cells was evaluated in a dentin barrier test device using erbium-doped yttrium, aluminum, and garnet (Er:YAG) laser-treated dentin. METHODS: The test materials (iBond(®), G-Bond™, and Vitrebond™) were applied on laser-treated or untreated dentin discs. After 24 h of exposure with perfusion of the test chamber, cell survival was evaluated by enzyme activity and related to a nontoxic control material. The mean values of control tissues were set to represent 100% viability. Data were analyzed using Kruskal-Wallis and Mann-Whitney U test. RESULTS: Vitrebond was the most toxic material for both laser-treated and untreated dentin. On untreated dentin, G-bond was cytotoxic to the pulp-derived cells (p < 0.05), and iBond was similar to the negative control group (p > 0.05). However, G-Bond and iBond were not cytotoxic when they were applied to Er:YAG laser-treated dentin (p > 0.05). CONCLUSION: Er:YAG laser treatment of dentin may protect the pulp cells from toxic substances of dentin contacting restorative materials; however, this effect is material related. Taking into consideration the limitations of this in vitro study, the Er:YAG laser treatment of dentin before restoration might be an option for decreasing the cytotoxic effects of the dental materials. Further research is required for clinical applications.