Wan Zaripah Wan Bakar

Susceptibility of selected tooth‐coloured dental materials to damage by common erosive acids

BACKGROUND Erosive substances such as gastric acids, lemon juice and even the less erosive cola drinks have been extensively investigated for their destructive effects on enamel. However, their effects on the tooth-coloured restoratives has not been widely analysed. The objective of this study was to assess their effects on the more commonly used glass containing restorative materials in vitro. MATERIALS AND METHODS Sixty-eight anterior and 24 molar tooth crowns had restorations placed of Fuji IX, Ketac Fil(+), Fuji II LC or Z100, and were painted with nail varnish to leave a 2 mm border around the restorations. Six ceramic crown surfaces were also included. The anterior crowns and porcelain samples were exposed to 0.113% HCl, 5.0% citric acid, 0.02% orthophosphoric acid or DDW for 2, 4, 8 or 16 hours at 37 degrees C. The molar restorations were exposed only for 16 hours. The surfaces of the anterior teeth were then examined by SEM to assess progressive stages of surface erosive etching. Depths of bulk loss of vulnerable restorative materials were measured in the remaining 24 molar teeth, and compared with depths of adjacent enamel loss, particularly at the margins, using Leika Microscope images of sections through these restorations. RESULTS The traditional glass ionomer cements (GICs) were severely eroded by the HCl and citric acid solutions even following two hours of exposure, with only minor damage from phosphoric acid at the concentration tested. These materials experienced considerable bulk loss by 16 hours, comparable to or greater than that in adjacent enamel. The margins of the GIC restorations experienced greater dissolution than the body of the restorations, particularly in citric acid. Z100 Resin Composite and porcelain restorations showed no effects at all, and Fuji II LC only minor damage. CONCLUSIONS The results demonstrate the effectiveness of porcelain and resin containing materials in providing protection of enamel in advanced cases of erosion. The traditional GIC materials are vulnerable to severe damage in patients experiencing strong citric acid or gastric acid induced erosion. However, there is evidence that protective benefits are still present and these materials should be used but only in closed sandwich restorations in such cases.

The effect of different sealer placement techniques on sealing Ability: An in vitro study.

Aim: The aim of this in vitro study was to evaluate the sealing ability of an endodontic sealer following different techniques of its placement. Materials and Methods: A total of 119 permanent human anterior teeth were prepared by using manual Protaper® and randomly divided into three equal groups of 33 teeth each. The teeth were obturated with the cold lateral condensation technique and AH26 sealer which was placed by using the following: G1: rotary lentulo spiral; G2: manual lentulo spiral; and G3: master gutta-percha coating. The remaining 20 teeth served as positive and negative controls. The samples were immersed in the methylene blue solution for 3 days and longitudinally sectioned for dye penetration assessment and analyzed using a stereomicroscope. Results: There was no statistically significant difference (P = 0.305) among the three groups. However, the rotary lentulo spiral technique and the master gutta-percha coating technique showed the highest (4.5 mm) and the lowest (3.8 mm) microleakage values, respectively. Conclusion: Different techniques of sealer placement used in this study provided a comparable seal. However, the master gutta-percha coating technique might be preferable because of its ease of use.

Different surface preparation techniques of porcelain repaired with composite resin and fracture resistance

Background: Porcelain from prosthesis such as crown or bridge can be fractured if exposed to trauma; and, can be repaired at chairside using composite resin. Aim: To investigate the fracture resistance of few techniques of surface preparation in repairing fractured porcelain using composite resin. Materials and Methods: Eighty samples of porcelain blocks were divided into 4 groups for different surface preparations, such as, Cimara repairing kit; porcelain etch kit containing hydrofluoric acid; Panavia F resin cement; and, sandblasting using aluminium oxide, before composite resin (Filtek Z250, 3M ESPE) was bonded to the prepared porcelain blocks. Twenty others samples in the control group comprised of pure porcelain blocks. The fracture resistance of each sample was tested using Instron machine (UK). Results: With the exception of the group repaired using hydrofluoric acid (3.04±1.04 Mpa), all the other groups showed significant difference in the fracture resistance values when compared to the control group (3.05 ± 1.42 MPa) at P<0.05. Conclusions: Etching of the porcelain blocks with hydrofluoric acid holds promise in the repair of fractured porcelain with composite resin at chairside.

Apical microleakage evaluation of system B compared with cold lateral technique: In vitro study.

The aim of this study was to evaluate in vitro the apical sealing ability of cold lateral and system B root filling techniques using dye penetration. Eighty-six extracted single-rooted human teeth were prepared and randomly divided into two experimental groups to be obturated by cold lateral condensation (n = 33) and system B (n = 33). The remaining 20 teeth served as positive and negative controls. The roots were embedded for 72 h in methylene blue dye solution and sectioned transversely for dye penetration evaluation using stereomicroscope. The results of this study showed that cold lateral condensation leaked significantly more (P < 0.001) than system B technique.

The assessment of surface roughness and microleakage of eroded tooth-colored dental restorative materials

Objectives: To investigate the effect of acidic solution on surface roughness and microleakage of tooth-colored restorative materials. Materials and Methods: A 160 box-shaped cavities were prepared on the buccal surfaces of 160 human molars, and assigned to four groups: Group A restored with Ketac™ Molar Easymix, Group B with Fuji II™ LC, Group C with Ketac™ N100, and Group D with Filtek™ Z250, and subdivided into study and control groups (n = 20). Study groups were immersed in lemon juice (pH = 2.79) for 24 h, whilst controlgroups in deionized distilled water. All samples were immersed in 2% methylene blue dye, sectioned into two equal halves for surface roughness, and microleakage tests. Data were analyzed using Mann–Whitney and Kruskal–Wallis tests at P < 0.05. Results: There was a significant difference in surface roughness of Ketac™ Molar, Fuji II™ LC, and Ketac™ N100. No significant difference was found in microleakage of Ketac™ Molar and Fuji II™ LC; however, there were significant differences in the gingival margin of Ketac™ N100, and the occlusal margin of Filtek™ Z250. Conclusions: All glass ionomer cements were eroded after exposure to the acidic drink. Filtek™ Z250 and Ketac™ Molar Easymix showed more microleakage. All materials showed more microleakage at the gingival margins.

Comparison of composite resin and porcelain inlays for restoration of noncarious cervical lesions: An In vitro study

Background: Composite resin (CR) currently is one of the most commonly used material in restoring noncarious cervical lesions (NCCL) due to its strength and esthetics color but has microleakage problem. The aim of this study is to compare in vitro the microleakage depth between CR and porcelain in restoring NCCL. Materials and Methods: This an in vitro study was done by preparing cavities on the buccocervical surface of 62 extracted premolar teeth which randomly assigned to two groups (n = 31) where Group 1 was restored with nanocomposite and Group 2 was cemented with porcelain cervical inlays. They were then subjected to thermocycling before immersion in 2% methylene blue dye for 24 h. Dye penetration depths were measured using Leica imaging system For statistical analysis, independent t-test was used to analyze the results (P < 0.05). Results: Porcelain cervical inlay restorations demonstrated statistically lesser microleakage depth for the cervical margins (P = 0.018) when compared to CR. Deeper microleakage depth at the cervical compared to coronal margins of CR (P = 0.006) but no significant difference of both margins for porcelain cervical inlays (P = 0.600). Conclusion: Porcelain cervical inlays show lesser microleakage than CR which could be alternative treatment option in restoring NCCL with better marginal seal and esthetics.

Fabrication of modified GIC: GIC-nanoSiO2-HA-ZrO2 using two different mixing methods

Conventional glass ionomer cement (GIC) is among the mostly used material in dentistry but some modifications were needed due to its deficiencies such as low mechanical strength and opacity. In this study, a new nanocomposite, GIC-nanoSiO2-HA-ZrO2 was fabricated whereby zirconia is added to improve the hardness. The nanocomposite of SiO2-HA-ZrO2 was synthesized using two different mixing methods which are one pot and spatulation methods. One pot method involved the addition of zirconia nanopowder during the one pot synthesis of nanoSiO2-HA and spatulation method involved the addition of zirconia nanopowder by controlled grinding process using mortar and pestle. Different weight percentage from 1-20 % of nanoSiO2-HA-ZrO2 was added to GIC and the hardness was analyzed using Vickers Tester. The one pot method recorded the highest and significant hardness value at 3 % addition which is ∼75.27 HV (± 2.48) compared to spatulation method ∼69.53 HV (± 7.78) at p < 0.05. Scanning Electron Microscope image from one...

C-shaped root canal.

Madam, A successful endodontic treatment very much depends on the endodontist’s ability to recognize unusual root canal anatomy. Most teeth have shown accessory canals, multiple foramina, fins and deltas.