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1.
Dental Press J Orthod ; 25(2): 44-51, 2020 03.
Article in English | MEDLINE | ID: mdl-32490926

ABSTRACT

OBJECTIVE: To evaluate facial profile changes promoted by polymethyl methacrylate (PMMA) cement graft to reduce excessive gingival display due to hyperactivity of the elevator muscles of the upper lip during smiling. METHODS: Eleven patients (all females, age range: 20 to 43 years) presenting gingival smile that were treated with PMMA cement grafts in a private clinic were selected for this retrospective study. Three angular and ten linear cephalometric facial profile measurements were performed preoperatively (baseline, T1) and at least 6 months postoperatively (T2). Differences between T1 and T2 were verified by Wilcoxon test, and the correlation between the thickness of the graft and facial profile changes was statistically evaluated by Spearman's Coefficient test. The significance level was set at p< 0.05. RESULTS: The nasolabial angle (p= 0.03) and the labial component of the nasolabial angle showed statistically significant differences (p= 0.04), with higher values in T2. No correlations were found between the graft thickness and the statistically significant facial profile changes (p> 0.05). CONCLUSIONS: The PMMA bone cement graft projected the upper lip forward, thereby increasing the nasolabial angle without affecting the nasal component. No correlations between the graft thickness and the facial profile changes were detected.


Subject(s)
Bone Cements , Smiling , Adult , Cephalometry , Female , Gingiva , Humans , Lip , Retrospective Studies , Young Adult
2.
J Am Dent Assoc ; 145(11): 1120-8, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25359643

ABSTRACT

BACKGROUND: Hemostatic agents have been used clinically in dentistry for many years to control bleeding. The authors reviewed scientific publications in which researchers investigated the effects of hemostatic agents on dentin and enamel surfaces and on bonding of adhesive systems and resin cements. TYPES OF STUDIES REVIEWED: The authors screened PubMed and Scopus databases for studies in English published from 1980 to 2013. They read the titles and abstracts to identify literature that fulfilled the inclusion criteria. The authors included studies in which researchers evaluated the hemostatic action on the dentin and enamel surfaces or its influence on the bond strength of adhesive systems or resin cements. They used cross-referencing to identify more articles. RESULTS: Twenty in vitro studies met the inclusion criteria. Investigators in 12 of these studies evaluated the bond strength to contaminated dentin. Investigators in 10 of these studies reported a significant decrease in bond strength. Those in two studies evaluated the influence of a hemostatic agent on the dental enamel and reported decreases in bond strength. Researchers also reported significant increases in microleakage of self-etching adhesives on contaminated dentin. Scanning electron microscopy revealed partial removal of the smear layer or an etching effect of dentin as a result of the application of hemostatic agents on dentin. PRACTICAL IMPLICATIONS: Adhesive procedures may be affected adversely when performed on dentin and enamel contaminated by hemostatic agents. Hemostatic agents may induce changes in the dentin surface morphology. The results of this review indicate that the bond strength of self-etching adhesive systems is affected more negatively than is that of etch-and-rinse systems. The authors found that a 60-second application of ethylenediaminetetraacetic acid followed by a water spray restored the bond strength of a self-etching adhesive to dentin; use of phosphoric acid for 15 seconds followed by a water spray also was an effective cleaning method. Direct comparison of selected studies was not possible, however, mainly because of methodological differences hampering definitive conclusions.


Subject(s)
Dental Bonding , Dental Cements/chemistry , Dental Enamel/drug effects , Dentin/drug effects , Hemostatics/chemistry , Acid Etching, Dental , Composite Resins/chemistry , Dental Stress Analysis , Dentin-Bonding Agents/chemistry , Microscopy, Electron, Scanning , Surface Properties
3.
Biomed Res Int ; 2014: 542678, 2014.
Article in English | MEDLINE | ID: mdl-25136595

ABSTRACT

This study evaluated the effect of fiber addiction in flexural properties of 30 wt% silica filled BisGMA resin (FR) or unfilled Bis-GMA (UR). Ten groups were created (N = 10) varying the resin (FR or UR) and quantity of glass fibers (wt%: 0, 10, 15, 20, and 30). Samples (10 × 2 × 1 mm) were submitted to flexural strength test following SEM examination. Data were analyzed by two-way ANOVA, Tukey, and Student t-test (α = 0.05). Results for flexural strength (MPa) were FR-groups: 0% (442.7 ± 140.6)(C), 10% (772.8 ± 446.3)(ABC), 15% (854.7 ± 297.3)(AB), 20% (863.4 ± 418.0)(A), 30% (459.5 ± 140.5)(BC); UR-groups: 0% (187.7 ± 120.3)(B), 10% (795.4 ± 688.1)(B), 15% (1999.9 ± 1258.6)(A), 20% (1911.5 ± 596.8)(A), and 30% (2090.6 ± 656.7)(A), and for flexural modulus (GPa) FR-groups: 0% (2065.63 ± 882.15)(B), 10% (4479.06 ± 3019.82)(AB), 15% (5694.89 ± 2790.3)(A), 20% (6042.11 ± 3392.13)(A), and 30% (2495.67 ± 1345.86)(B); UR-groups: 0% (1090.08 ± 708.81)(C), 10% (7032.13 ± 7864.53)(BC), 15% (19331.57 ± 16759.12)(AB), 20% (15726.03 ± 8035.09)(AB), and 30% (29364.37 ± 13928.96)(A). Fiber addiction in BisGMA resin increases flexural properties, and the interaction between resin and fibers seems better in the absence of inorganic fillers increasing flexural properties.


Subject(s)
Composite Resins/chemistry , Glass/chemistry , Materials Testing
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