Print ISSN: 1812-1217

Online ISSN: 1998-0345

Keywords : Tensile


Evaluation the Effect of Different Methods of Disinfection on Tensile Strength and Bond Strength of Soft Denture Lining Materials

Lamia T Rejab; Ihssan F Al-Taka

Al-Rafidain Dental Journal, Volume 13, Issue 1, Pages 58-65
DOI: 10.33899/rden.2012.84680

Aims: Aim of the study to evaluate the effect of two different disinfection methods for two periods of time on tensile strength and bond strength of soft denture lining materials (Vertex and Molloplast-B). Materials and methods : The effect of two disinfection methods ,first chemical disinfection method (which include artificial saliva , saturated salt and vinegar solution), and second microwave method on two physical properties the tensile and bond strength of soft denture lining materials for two periods of times (14 and 30 days) was evaluated, two hundred samples were prepared, one hundred samples to each property test . ANOVA and Duncan's multiple range test were performed to determine the signifi-cant difference among the tested groups at p ≤ 0.05% . Results: The result showed that the highest val-ue of tensile and bond strength of Vertex after 14 and 30 days were achieved with the microwave group, while for Molloplast -B highest value achieved with the control distilled water group. The low-est value was achieved after immersion in vinegar group for both soft lining material. A significant difference between the two soft lining materials among all disinfection methods at p≤ 0.05.Conclusions : The results appeared that the chemical disinfection and microwave disinfection methods have a significant effect on the tensile strength and bond strength of both vertex and Mol-loplast –B soft ling materials for two periods of time. Microwave disinfection has less effect than the chemical disinfection on the properties. The effect of disinfection increase significantly with increas-ing period of time .

Tensile Bond Strength of Brackets After Antioxidant Treatment on Bleached Teeth

Ne'am F Agha; Rayia J Al-Naimi; Omer H Al-Liwaizi

Al-Rafidain Dental Journal, Volume 10, Issue 1, Pages 186-191

Aims: To determine the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with to human enamel after bleaching. Materials and Methods: Thirty two sound human maxillary and mandibular premolars extracted for orthodontic reasons were collected. All teeth had undamaged buccal enamel, no caries and no pre-treatment with any chemicals. They were then stored in a solution of 0.1 % thymol before the experiment. Results: In the present study, we found that , tensile bond strength in group of direct bonding after bleaching was lower than other groups when compared with control group and the difference was significant at level p< 0.05 . The present investigation confirmed that waiting for a period of 7 days after bleaching is sufficient to obtain ade-quate tensile bond strength for clinical conditions. There was significant difference in tensile bond strength when the brackets that underwent direct bonding and ethanol with control group. No signifi-cant difference in tensile bond strength was observed when compared with the bracket immersed in a distilled water & with control bracket. Conclusions: In the present study we found that , tensile bond strength in group of direct bonding after bleaching were the lowest than other groups and when com-pared with the control group, the difference is significant. There was a significant difference in tensile bond strength when comparing the group that underwent direct bonding with control group.

The Bond Strength of the Bonded Bracket to Enamel Surface Treated with Acid and Microetcher

Hussain A Obaidi; Muzahim H Hanna

Al-Rafidain Dental Journal, Volume 9, Issue 1, Pages 71-76

Aims: To evaluate shear and tensile bond strengths of the bonded brackets to the enamel surfaces treated with acid and microetcher. Materials and methods: The sample include 30 intact extracted
upper left first premolars, the teeth were collected from orthodontics clinic and private clinics. The sample was grouped into three groups (10 teeth for each group), which were: acid etched, microetched
at 5mm distance, and microetched at 10mm distance.. Stainless steel brackets (Roth System) were bonded to the buccal enamel surfaces utilizing light cure composite (transbondTM XT) according to the
manufacturer instructions. All the groups were thermocycled, the temperature range is 5 + 3 ºC to 50 + 3 ºC with a 30 seconds dwell time in each bath. The shear and tensile bond strengths of the bonded
bracket were measured by using the shear and tensile Universal testing machine. The results were analyzed statistically; that include: Descriptive, ANOVA and Duncan’s testes at p≤ 0.05 significant level.
Results: It was reveled that the shear and tensile bond strength values of the bonded brackets to enamel treated with the acid were greater significantly than that treated with microetcher. Conclusions: The
acid agent is considered the most practical conditioner to the enamel to achieve strong shear and tensile bond strengths.