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Effect of recycling protocol on mechanical strength of used mini-implants.

Estelita S, Janson G, Chiqueto K, Ferreira ES - Int J Dent (2014)

Bottom Line: Results.Screw diameter was the only variable that affected FT.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, Faculty of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492 Bairro Santana, 90035-003 Porto Alegre, RS, Brazil.

ABSTRACT
Purpose. This study evaluated the influence of recycling process on the torsional strength of mini-implants. Materials and Methods. Two hundred mini-implants were divided into 4 groups with 50 screws equally distributed in five diameters (1.3 to 1.7 mm): control group (CG): unused mini-implants, G1: mini-implants inserted in pig iliac bone and removed, G2: same protocol of group 1 followed by sonication for cleaning and autoclave sterilization, and G3: same insertion protocol of group 1 followed by sonication for cleaning before and after sandblasting (Al2O3-90 µ) and autoclave sterilization. G2 and G3 mini-implants were weighed after recycling process to evaluate weight loss (W). All the screws were broken to determine the fracture torque (FT). The influence of recycling process on FT and W was evaluated by ANOVA, Mann-Whitney, and multiple linear regression analysis. Results. FT was not influenced by recycling protocols even when sandblasting was added. Sandblasting caused weight loss due to abrasive mechanical stripping of screw surface. Screw diameter was the only variable that affected FT. Conclusions. Torsional strengths of screws that underwent the recycling protocols were not changed. Thus, screw diameter choice can be a more critical step to avoid screw fracture than recycling decision.

No MeSH data available.


Related in: MedlinePlus

The equipment used for bone screw insertion in high-density artificial bone (0.80 g/cm3) and fracture.
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Related In: Results  -  Collection


getmorefigures.php?uid=PMC4127219&req=5

fig1: The equipment used for bone screw insertion in high-density artificial bone (0.80 g/cm3) and fracture.

Mentions: Fifty new bone screws (control group, CG) were inserted in high-density artificial bone (0.80 g/cm3, Sawbones Division of Pacific Research Laboratories, Vashon Island, Wash, ASTM F1839-08) to achieve a torque value able to cause torsional fracture of the screws (Fracture Torque, FT). An essay machine equipped with a screwdriver fit to a digital torquimeter was used for bone screw insertion, perpendicularly to artificial bone blocks, to achieve fracture torque values that were measured in Newtons per centimeter (Figure 1).


Effect of recycling protocol on mechanical strength of used mini-implants.

Estelita S, Janson G, Chiqueto K, Ferreira ES - Int J Dent (2014)

The equipment used for bone screw insertion in high-density artificial bone (0.80 g/cm3) and fracture.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4127219&req=5

fig1: The equipment used for bone screw insertion in high-density artificial bone (0.80 g/cm3) and fracture.
Mentions: Fifty new bone screws (control group, CG) were inserted in high-density artificial bone (0.80 g/cm3, Sawbones Division of Pacific Research Laboratories, Vashon Island, Wash, ASTM F1839-08) to achieve a torque value able to cause torsional fracture of the screws (Fracture Torque, FT). An essay machine equipped with a screwdriver fit to a digital torquimeter was used for bone screw insertion, perpendicularly to artificial bone blocks, to achieve fracture torque values that were measured in Newtons per centimeter (Figure 1).

Bottom Line: Results.Screw diameter was the only variable that affected FT.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, Faculty of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492 Bairro Santana, 90035-003 Porto Alegre, RS, Brazil.

ABSTRACT
Purpose. This study evaluated the influence of recycling process on the torsional strength of mini-implants. Materials and Methods. Two hundred mini-implants were divided into 4 groups with 50 screws equally distributed in five diameters (1.3 to 1.7 mm): control group (CG): unused mini-implants, G1: mini-implants inserted in pig iliac bone and removed, G2: same protocol of group 1 followed by sonication for cleaning and autoclave sterilization, and G3: same insertion protocol of group 1 followed by sonication for cleaning before and after sandblasting (Al2O3-90 µ) and autoclave sterilization. G2 and G3 mini-implants were weighed after recycling process to evaluate weight loss (W). All the screws were broken to determine the fracture torque (FT). The influence of recycling process on FT and W was evaluated by ANOVA, Mann-Whitney, and multiple linear regression analysis. Results. FT was not influenced by recycling protocols even when sandblasting was added. Sandblasting caused weight loss due to abrasive mechanical stripping of screw surface. Screw diameter was the only variable that affected FT. Conclusions. Torsional strengths of screws that underwent the recycling protocols were not changed. Thus, screw diameter choice can be a more critical step to avoid screw fracture than recycling decision.

No MeSH data available.


Related in: MedlinePlus