- Email: [email protected]
Polishing systems
Discussion.—Changes in material for restorations were more likely when the treatment chosen was a replacement rather than a repair, when the tooth was not a molar, when the tooth was in the maxillary arch, and when the original restoration involved a single surface. Amalgam was not often used to repair or replace defective restorations. Instead, practitioners often chose to use direct toothcolored materials.
Clinical Significance.—The replacement of amalgam restorations is usually done because of its inferior esthetic appearance, some alleged adverse health consequences, and environmental concerns. Clinicians are significantly more likely to use tooth-colored materials and
eliminate amalgam restorations. Amalgam has been banned from some European countries, especially those in the Scandinavian region.
Gordan VV, Riley JL III, Worley DC, et al: Restorative material and other tooth-specific variables associated with the decision to repair or replace defective restorations: findings form the dental PBRN. J Dent 40:397-405, 2012 Reprints available from VV Gordan, Dept. of Restorative Dental Sciences, Univ. of Florida, College of Dentistry, P.O. Box 100415, Gainesville, FL 32610-0415, USA; fax: þ1 352 273 7970; e-mail: [email protected]
Polishing systems Background.—Resin composites are widely used to directly restore anterior and posterior teeth. Their advantages include a simple bonding procedure, desirable esthetic appearance, and improved physical and mechanical properties. Nanotechnology now permits the production of functional materials and structures in the range of 1-100 nm using various physical and chemical methods. Resin composites containing nanoparticles offer improved filler technology, modified organic matrices, and a higher level of polymerization, which improves the material’s mechanical and physical properties. Having a smooth surface finish is essential clinically, determining the esthetics and longevity of composite restorations. Smooth surfaces also add to patient comfort. Resin-based composite materials have intrinsic properties that are critical to achieving a clinically successful restoration, including hardness and strength. Hardness predicts the degree of cure; restorations that are not properly polymerized can have a softer surface that retains scratches created during finishing procedures. These scratches can compromise fatigue strength and lead to a restoration’s premature failure. The smoothest composite surface is achieved under a polyester matrix film, but this surface is usually removed under finishing procedures that produce a harder, more resistant, and more esthetically acceptable surface. Finishing and polishing reduce the roughness and scratches on teeth. Multi-step aluminum oxide, graded, abrasive, flexible finishing and polishing disks are used to smooth the surface. The surface roughness and microhardness of three resin composites containing nanoparticles after polishing using a one-step or conventional multi-step polishing systems were
evaluated, with the expectation that there would be no difference in these parameters between the polished resin composites or the different polishing systems used for the same resin composites. Methods.—One hundred twenty-six samples measuring 10 2 mm were prepared using a metal mold and the nanofil composite Filtek Supreme XT or the nanohybrids Ceram-X and Grandio, with 21 specimens of each composite for both tests (63 total for each test). After light curing, seven specimens from each group remained untouched and served as controls. For polishing, samples were randomly assigned to the PoGo and Sof-Lex systems for 30 s after being wet-ground with 1200-grit silicon carbide paper. A profilometer was used to determine mean surface roughness of the polished specimens. A Vickers hardness measuring instrument determined the microhardness of the specimens under a 200-g load with 15 seconds of dwell time. Results.—For all materials the smoothest surfaces were those of the controls. The PoGo and Sof-Lex systems obtained equally smooth surfaces in all three materials. Roughness values did not differ significantly between the systems and materials. The smoothest surface was the control sample of Filtek Supreme XT, which was significantly smoother than the Ceram-X and Grandio samples. The lowest hardness values were found for the control samples, which differed significantly from the polished samples. Ceram-X samples had the least microhardness,
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followed by Filtek Supreme XT and then Grandio. No statistically significant differences were noted between the results of the two polishing systems. Discussion.—The one-step and multi-step polishing systems produced comparable degrees of smoothness and hardness values. The one-step system may be preferable because it requires a single procedure.
Clinical Significance.—Regardless of the polishing system used, Filtek Supreme XT and Ceram-X showed smoother surfaces and lower microhardness than Grandio resin composite, although the differences were not significant. The one-step and multi-step polishing
procedures both decreased the smoothness that was obtained with matrix strips. The one-step polishing system may be preferable for polishing resin composite restorations, but the results with both systems are comparable.
Erdemir U, Sancakli HS, Yildiz E: The effect of one-step and multistep polishing systems on the surface roughness and microhardness of novel resin composites. Eur J Dent 6:198-205, 2012 Reprints available from U Erdemir, Istanbul Universitesi, Dishekimligi Fakultesi, Restoratif Dishekimligi ve Endodonti AD, 34093 Capa, Istanbul, Turkiye; fax: þ90 212 5250075; e-mail: [email protected]
Sleep Apnea Dental side effects of oral appliance therapy Background.—Patients with obstructive sleep apnea syndrome (OSAS) experience repeated episodes of pharyngeal collapse and increased airflow resistance during sleep, which often features heavy snoring. As a result, the patient has excessive daytime sleepiness, sexual dysfunction, neurocognitive deficits, and higher rates of cardiovascular and cerebrovascular morbidity and mortality. OSAS severity is indicated through the apnea-hypopnea index (AHI) and can be mild (AHI 5-15), moderate (AHI 15-30), or severe (AHI exceeding 30). Treatment with continuous positive airway pressure (CPAP) is highly efficacious but its effectiveness is compromised by poor patient compliance. Oral appliance therapy offers an alternative and is designed to enlarge the upper airway during sleep by holding the mandible in a forward and downward position. Oral appliances are most effective for patients with mild or moderate OSAS but can also be used for patients who are unwilling or unable to tolerate CPAP. Among the common side effects associated with oral appliance therapy are tooth pain, TMJ pain, myofascial pain, dry mouth, excessive salivation, and gum irritation, but these are usually mild and considered transient. An investigation was done to identify the dental side effects that occur with long-term oral appliance therapy compared to CPAP and the relationship between the mean mandibular protrusion and the degree of dental side effects that develop. Methods.—Fifty-one patients were randomly assigned to treatment with oral appliance therapy and 52
220
Dental Abstracts
to CPAP. Dental plaster study models in full occlusion were made at baseline and after 2 years of therapy. Twenty-nine oral appliance patients and 34 CPAP patients were included in the analysis of changes in occlusion and other variables and in comparisons between the two treatment groups. Results.—The oral appliance group had a significant decrease in overbite (1.2 mm) and overjet (1.5 mm) compared to the CPAP group. There was also a significantly larger anterior–posterior change in occlusion for the oral appliance versus the CPAP group. The oral appliance group had a significant association between the change in overbite and the amount of mandibular protrusion, but this relationship was not noted in the CPAP group. Both groups demonstrated a significant decline in the number of occlusal contact points in the (pre)molar region. There were no significant differences in the interproximal spaces for the upper and lower arch between the two groups. Oral appliance therapy for 2 years tended to move the occlusion toward a mesioocclusion compared to CPAP therapy. Bilateral crossbite in the (pre)molar region was also associated with the oral appliance, as were shifts from class I to class III in molar and cuspid occlusion or from class II to class I or II. Discussion.—Oral appliance therapy demonstrated a decrease in overjet, overbite, and number of occlusal contact points as well as altered anterior–posterior relationships. The decrease in overbite was statistically associated
Clinical Significance.—The replacement of amalgam restorations is usually done because of its inferior esthetic appearance, some alleged adverse health consequences, and environmental concerns. Clinicians are significantly more likely to use tooth-colored materials and
eliminate amalgam restorations. Amalgam has been banned from some European countries, especially those in the Scandinavian region.
Gordan VV, Riley JL III, Worley DC, et al: Restorative material and other tooth-specific variables associated with the decision to repair or replace defective restorations: findings form the dental PBRN. J Dent 40:397-405, 2012 Reprints available from VV Gordan, Dept. of Restorative Dental Sciences, Univ. of Florida, College of Dentistry, P.O. Box 100415, Gainesville, FL 32610-0415, USA; fax: þ1 352 273 7970; e-mail: [email protected]
Polishing systems Background.—Resin composites are widely used to directly restore anterior and posterior teeth. Their advantages include a simple bonding procedure, desirable esthetic appearance, and improved physical and mechanical properties. Nanotechnology now permits the production of functional materials and structures in the range of 1-100 nm using various physical and chemical methods. Resin composites containing nanoparticles offer improved filler technology, modified organic matrices, and a higher level of polymerization, which improves the material’s mechanical and physical properties. Having a smooth surface finish is essential clinically, determining the esthetics and longevity of composite restorations. Smooth surfaces also add to patient comfort. Resin-based composite materials have intrinsic properties that are critical to achieving a clinically successful restoration, including hardness and strength. Hardness predicts the degree of cure; restorations that are not properly polymerized can have a softer surface that retains scratches created during finishing procedures. These scratches can compromise fatigue strength and lead to a restoration’s premature failure. The smoothest composite surface is achieved under a polyester matrix film, but this surface is usually removed under finishing procedures that produce a harder, more resistant, and more esthetically acceptable surface. Finishing and polishing reduce the roughness and scratches on teeth. Multi-step aluminum oxide, graded, abrasive, flexible finishing and polishing disks are used to smooth the surface. The surface roughness and microhardness of three resin composites containing nanoparticles after polishing using a one-step or conventional multi-step polishing systems were
evaluated, with the expectation that there would be no difference in these parameters between the polished resin composites or the different polishing systems used for the same resin composites. Methods.—One hundred twenty-six samples measuring 10 2 mm were prepared using a metal mold and the nanofil composite Filtek Supreme XT or the nanohybrids Ceram-X and Grandio, with 21 specimens of each composite for both tests (63 total for each test). After light curing, seven specimens from each group remained untouched and served as controls. For polishing, samples were randomly assigned to the PoGo and Sof-Lex systems for 30 s after being wet-ground with 1200-grit silicon carbide paper. A profilometer was used to determine mean surface roughness of the polished specimens. A Vickers hardness measuring instrument determined the microhardness of the specimens under a 200-g load with 15 seconds of dwell time. Results.—For all materials the smoothest surfaces were those of the controls. The PoGo and Sof-Lex systems obtained equally smooth surfaces in all three materials. Roughness values did not differ significantly between the systems and materials. The smoothest surface was the control sample of Filtek Supreme XT, which was significantly smoother than the Ceram-X and Grandio samples. The lowest hardness values were found for the control samples, which differed significantly from the polished samples. Ceram-X samples had the least microhardness,
Volume 58
Issue 4
2013
219
followed by Filtek Supreme XT and then Grandio. No statistically significant differences were noted between the results of the two polishing systems. Discussion.—The one-step and multi-step polishing systems produced comparable degrees of smoothness and hardness values. The one-step system may be preferable because it requires a single procedure.
Clinical Significance.—Regardless of the polishing system used, Filtek Supreme XT and Ceram-X showed smoother surfaces and lower microhardness than Grandio resin composite, although the differences were not significant. The one-step and multi-step polishing
procedures both decreased the smoothness that was obtained with matrix strips. The one-step polishing system may be preferable for polishing resin composite restorations, but the results with both systems are comparable.
Erdemir U, Sancakli HS, Yildiz E: The effect of one-step and multistep polishing systems on the surface roughness and microhardness of novel resin composites. Eur J Dent 6:198-205, 2012 Reprints available from U Erdemir, Istanbul Universitesi, Dishekimligi Fakultesi, Restoratif Dishekimligi ve Endodonti AD, 34093 Capa, Istanbul, Turkiye; fax: þ90 212 5250075; e-mail: [email protected]
Sleep Apnea Dental side effects of oral appliance therapy Background.—Patients with obstructive sleep apnea syndrome (OSAS) experience repeated episodes of pharyngeal collapse and increased airflow resistance during sleep, which often features heavy snoring. As a result, the patient has excessive daytime sleepiness, sexual dysfunction, neurocognitive deficits, and higher rates of cardiovascular and cerebrovascular morbidity and mortality. OSAS severity is indicated through the apnea-hypopnea index (AHI) and can be mild (AHI 5-15), moderate (AHI 15-30), or severe (AHI exceeding 30). Treatment with continuous positive airway pressure (CPAP) is highly efficacious but its effectiveness is compromised by poor patient compliance. Oral appliance therapy offers an alternative and is designed to enlarge the upper airway during sleep by holding the mandible in a forward and downward position. Oral appliances are most effective for patients with mild or moderate OSAS but can also be used for patients who are unwilling or unable to tolerate CPAP. Among the common side effects associated with oral appliance therapy are tooth pain, TMJ pain, myofascial pain, dry mouth, excessive salivation, and gum irritation, but these are usually mild and considered transient. An investigation was done to identify the dental side effects that occur with long-term oral appliance therapy compared to CPAP and the relationship between the mean mandibular protrusion and the degree of dental side effects that develop. Methods.—Fifty-one patients were randomly assigned to treatment with oral appliance therapy and 52
220
Dental Abstracts
to CPAP. Dental plaster study models in full occlusion were made at baseline and after 2 years of therapy. Twenty-nine oral appliance patients and 34 CPAP patients were included in the analysis of changes in occlusion and other variables and in comparisons between the two treatment groups. Results.—The oral appliance group had a significant decrease in overbite (1.2 mm) and overjet (1.5 mm) compared to the CPAP group. There was also a significantly larger anterior–posterior change in occlusion for the oral appliance versus the CPAP group. The oral appliance group had a significant association between the change in overbite and the amount of mandibular protrusion, but this relationship was not noted in the CPAP group. Both groups demonstrated a significant decline in the number of occlusal contact points in the (pre)molar region. There were no significant differences in the interproximal spaces for the upper and lower arch between the two groups. Oral appliance therapy for 2 years tended to move the occlusion toward a mesioocclusion compared to CPAP therapy. Bilateral crossbite in the (pre)molar region was also associated with the oral appliance, as were shifts from class I to class III in molar and cuspid occlusion or from class II to class I or II. Discussion.—Oral appliance therapy demonstrated a decrease in overjet, overbite, and number of occlusal contact points as well as altered anterior–posterior relationships. The decrease in overbite was statistically associated