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Influence of prosthetic screw material on joint stability in passive and non-passive implant-supported dentures.

Spazzin AO, Henriques GE, de Arruda Nóbilo MA, Consani RL, Correr-Sobrinho L, Mesquita MF - Open Dent J (2009)

Bottom Line: Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05).No significant interaction was found between fit level and screw material (p=0.199).Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics and Periodontics, Dental School of Piracicaba, State University of Campinas, 901 Avenue Limeira, Piracicaba, SP 13414-903, Brazil.

ABSTRACT

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit.

Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05).

Results: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

No MeSH data available.


Schematic illustrations of the two fit conditions submitted to the one-screw test: (A) passive fit; (B) non-passive fit.
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Figure 4: Schematic illustrations of the two fit conditions submitted to the one-screw test: (A) passive fit; (B) non-passive fit.

Mentions: Twenty cast models (10 for passive fit and 10 for non-passive fit) were fabricated using the prosthetic structures maintaining the positions of the abutment analogs to simulate the two fit levels tested. Assembly of the components as regards the fit levels is shown in Fig. (2). For the passive fit, no rings were used between the abutment analogs (Conexão Prostheses Systems) and framework cylinders of the dentures. For the non-passive fit, three rings of different thicknesses (100, 200 and 300 μm, one for each abutment analog, respectively) were used between three of the framework cylinders of the dentures and the abutment analogs (C, D and E); the other abutment analogs (A and B) were screwed directly to the framework cylinders. All these sets were invested in stone cast (type VI Herostone; Vigodent, Rio de Janeiro, RJ, Brazil) using a delineator to standardize the investment procedure (Fig. 3). The rings were added to create a vertical misfit of approximately 250 µm in the one-screw test adapted from Tan et al. (1993) [17]; this test was then used to quantify the two fit levels tested (Fig. 4).


Influence of prosthetic screw material on joint stability in passive and non-passive implant-supported dentures.

Spazzin AO, Henriques GE, de Arruda Nóbilo MA, Consani RL, Correr-Sobrinho L, Mesquita MF - Open Dent J (2009)

Schematic illustrations of the two fit conditions submitted to the one-screw test: (A) passive fit; (B) non-passive fit.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2819699&req=5

Figure 4: Schematic illustrations of the two fit conditions submitted to the one-screw test: (A) passive fit; (B) non-passive fit.
Mentions: Twenty cast models (10 for passive fit and 10 for non-passive fit) were fabricated using the prosthetic structures maintaining the positions of the abutment analogs to simulate the two fit levels tested. Assembly of the components as regards the fit levels is shown in Fig. (2). For the passive fit, no rings were used between the abutment analogs (Conexão Prostheses Systems) and framework cylinders of the dentures. For the non-passive fit, three rings of different thicknesses (100, 200 and 300 μm, one for each abutment analog, respectively) were used between three of the framework cylinders of the dentures and the abutment analogs (C, D and E); the other abutment analogs (A and B) were screwed directly to the framework cylinders. All these sets were invested in stone cast (type VI Herostone; Vigodent, Rio de Janeiro, RJ, Brazil) using a delineator to standardize the investment procedure (Fig. 3). The rings were added to create a vertical misfit of approximately 250 µm in the one-screw test adapted from Tan et al. (1993) [17]; this test was then used to quantify the two fit levels tested (Fig. 4).

Bottom Line: Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05).No significant interaction was found between fit level and screw material (p=0.199).Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics and Periodontics, Dental School of Piracicaba, State University of Campinas, 901 Avenue Limeira, Piracicaba, SP 13414-903, Brazil.

ABSTRACT

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit.

Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05).

Results: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

No MeSH data available.