ABSTRACT
Treatment of hypersensitivity and dentinal tubules occlusion which have been a non-consistent and controversial issue was investigated in vitro and in vivo in this study. The in vivo study comprised forty five volunteer geriatric patients from both sexes taken from geriatric institutions, their age ranged from 55-65 years. Each patient had one of their sensitive teeth treated with a placebo solution and the remaining sensitive teeth were treated either by potassium oxalate containing agent [Super seal] or sodium silicate agent. Sensitivity was then tested after 1 week, 2 weeks and 3 weeks respectively using a visual analog scale [VAS] in order to show their clinical effect on the level of discomfort and pain responses for those complaining from hypersensitivity. Furthermore, an in vitro study was done in order to determine the role of these agents in obliteration of opened sensitive dentinal tubules using scanning electron microscope examination and computer digital analysis photomicrograph. The diameter of dentinal tubules were calculated by stained red pixels augmented with histological polarized light appearance photographs. All the qualitative and quantitative findings were then statistically analyzed. Results showed that the oxalate containing solution revealed an immediate increase in the mean value toward " no pain" followed by slight decrease. Also their in-vitro specimen showed a marked reduction in the opening of dentinal tubules by it with large calcium oxalate crystals decreasing its diameter approx. to 2.39% compared with the control specimens with diameter 8.21%. while the silicate specimen showed a slight reduction in dentinal tubule diameter by deposition of small silica particles which takes time to act as a nuclear template for minerals deposition decreasing tubules diameter to 5.10% respectively
ABSTRACT
The simplicity of reattaching a fractured segment following dental trauma is astonishing to the dentist as well as the patient. Since the development of adhesive dentistry, reattachment of a fractured tooth fragment has become more and more accepted. Patients would prefer to keep their own tooth even if reattachment would not necessarily provide long-term durability. This study aimed to infer the long-term success rate of reattachment techniques through testing the fracture resistance and microleakage of anterior fractured teeth reattached using different techniques and materials, compare it to tooth's original fracture resistance, and to that of conventional resin composite buildup. Seventy five sound human.incisors were fractured using a universal testing machine by applying a perpendicular, force in a labial-to-lingual direction at a crosshead speed of 1.0 mm/min. The teeth were divided into five groups of 15 teeth each; according to the technique used for reattachment; Group I: simple reattachment, Group II: reattachment and placement of silica at the interface, Group III: reattachment and placement of chamfer at the interface, Group IV: reattachment and internal groove preparation inside the tooth, and Group V: composite build up [Control]. Each group was further subdivided into three subgroups of 5 teeth each, according to the material used. In subgroup 1 reattachment of tooth fragment was performed using Excite adhesive system, in subgroup 2 Tetric Flow resin composite, while in subgroup 3 Rely X dual ci microg resin cement was utilized. The teeth were then immersed in 1% aqueous solution of Mythelene Blue dye for 4 hours to assess microleakage at the interface. The specimens were loaded in a universal testing machine as before until failure. The force required to detach each fragment was recorded. For each tooth, the fracture strength was expressed as a percentage of the load required to fracture the sound tooth [% strength recovery]. The teeth were then assessed for microleakage along the fractured interface using a binocular stereomicroscope and given a score according to the extent of d
ABSTRACT
The purpose of this in vitro study was two-fold. First the effectiveness of ozone, as a bleaching agent, in comparison with other commercJaJJy available bleaching products was evaluated by measuring the change in color index of teeth. Second the presence of any surface damages, which may occur in enamel surface following bleaching, was investigated by measuring the surface roughness of enamel as this may have an implication on the functional properties of the surface. One bleaching gel with two different concentrations [Opalescence 10% and 20%], and an Ozone gas [O3] were used in this study. The Ozone was incorporated into: 10% carbamide peroxide gel, neutral KY gel and distilled water. Twenty five intact maxillary first premolars were used. The teeth were randomly divided into five groups. Group J was treated with ozonated 10% carbamide peroxide, group fl was exposed to ozonated water, group III was treated with ozonated KY gel, group IV and V were subjected to 10% and 20% carbamide peroxide respectively. For each specimen, a photomicrograph was undertaken before and after treatment by a digital camera attached to a zoom stereo microscope. The tricolor index (RGB system) for brightness index measurement and the surface roughness (Ra) 'were automatically calculated using image analysis software. The value of the blue color parameter was specifically registered.
Results: There was no statistically significant difference between the control and the experimental specimens for the groups I, II and IV [p > 0.05]. However, by looking at the results of the blue color paramcL-r; there was a statistically significant difference between the control and the experimental speomens of group IV. This difference was not observed for group I and JI respectively. Regarding groups III and V a significant difference in color index and blue color parameter was observed between the control and the experimental specimens [p< 0.05] indicating a good brightness effect. By comparing the changes in color indices of the five groups, there was a statistically significant difference [p< 0.05] among them. Groups III and V showed a significantly higher color index than the other groups. The most effective bleaching regimen was obtained when the teeth were treated with 20% carbamide peroxide and ozonated KY gel respectively. In general, there was an increase in the 1 average surface roughness [Ra] with all different treatments. By comparing the surface roughness of the five groups, there was a statistically significant difference between the five groups and they were ranked as follow [from the lowest to the highest]: Group II, Group I, Group IV, Group III and Group V. Pearson correlation coefficient showed no correlation between the color iadex -and Ra for group I, while the correlation between color indices and Ra for the rest of the groups were not statistically significant. In general, no relation between surface roughness and color index could be established.
Conclusions: The use of Ozone is an effective and viable method for bleaching teeth. Bleaching has an adverse effect on the surface roughness of enamel. Although the correlation between the color index and the surface roughness was not significant, yet there was a trend showing that the brighter the bleached teeth the higher the surface roughness. The change in the blue color parameter is an appropriate descriptor of brightness. Clinical Relevance The use of Ozone as a bleaching agent should provide a fast, effective and harmless method to whiten teeth. It should be easily supplied and integrated in dental offices. The potential adverse effects of bleaching must be known to the dentist in order to be able to overcome these effects. Clinically, brightness index from computer analysis of digitized photographic images may be useful for monitoring the effectiveness of bleaching.
ABSTRACT
This study was conducted to investigate the effect of chemo-mechanical caries removal on the chemistry and morphology of carious dentin and on subsequent dentin adhesion. A total of 52 carious third molar teeth were used. Twenty teeth were used for chemical analysis and morphological analysis using energy dispersive spectroscope and scanning electron microscope, respectively. Twenty teeth were used for shear bond strength measurements, and twelve teeth for evaluating the microstructure of resin dentin interface. The teeth were divided into four groups: Group I is carisolv treated dentin, group II dentin is treated with carisolv followed by phosphoric acid etching, group III is carisolv followed by sodium hypochlorite while group IV is carisolv followed by self-etching primer. In the chemical analysis results, the highest peak heights for calcium and phosphorous were recorded for group I, followed by group III, then followed by group IV, while the least peak heights were recorded for group II. Scanning electron photomicrographs of dentin after caries removal using carisolv and different treatments revealed the removal of the smear layer, opening of the dentinal tubules and morphological alteration of the intertubular dentin. While scanning electron photomicrographs of the resin-dentin interface revealed an acid resistant resin dentin interdiffusion zone, irrespective of the surface treatment performed. The mean shear bond strength values for group I, III and IV were 16.64 MPa, 14.97 MPa and 15.52 MPa respectively, and the difference was statistically insignificant. Group II showed the lowest mean shear bond strength value of 9.55 MPa and the difference was statistically significant from the three other groups. It was concluded that dentin surface after chemo-mechanical caries removal is sound, mineralized and very suitable for restoration. Bonding to carisolv treated dentin is dependant on the adhesive system used; a separate etching step is not indicated, while deproteinization of carisolv treated dentin or the use of self-etching primer is a viable bonding protocol
Clinical Relevance: To achieve successful bonding to Carisolv treated dentin, the etching step should be omitted from the regular bonding procedure. The dentist should shift to the primer step directly, or use self-etching primers