The Effect of Immediate Obturator Reconstruction after Radical Maxillary Resections on Speech and other Functions.

OBJECTIVE: Maxillectomy often results in a high level of morbidity with significant psychological and functional implications for patients. The aims of the present study were to assess the effectiveness of the maxillary obturator as a speech rehabilitation aid, to examine the influence of dentition on speech intelligibility, to restore patients’ regular daily activity as soon as possible, and to maintain patients’ psychological well-being throughout the treatment. PATIENTS AND METHODS: Forty-one palatomaxillary immediate obturator and definitive reconstruction patient treatments were reviewed at a clinic (Ankara, Turkey). Patients aged between 20 and 73 years with surgically acquired partial maxillary defects were included in this study. All patients were rehabilitated with immediate and definitive obturators. The patients were given immediate surgical obturators which were adjusted to the defect area with a tissue conditioner. By employing this procedure and relining with the tissue conditioner weekly, immediate obturators were used in the interim stage of the treatment. As interim obturators, prostheses were used for two to three months until healing and resorption were found satisfactory, after which the definitive obturators were fabricated. RESULTS: The speech intelligibility test (SIT) was employed for the evaluation of the speech ability. Significant improvements were found in the mean speech intelligibility test score (SITS), from 0.02% in patients without prosthetic obturation to 94.10% in patients with immediate obturation on the second day, 95.60% in patients with immediate obturation on the 20th day, and 95.97% in patients with definitive obturation.

The effect of repeated porcelain firings on corrosion resistance of different dental alloys.

PURPOSE: The aim of this study was to evaluate the effects of repeated porcelain firing process on the corrosion rates of the dental alloys. MATERIALS AND METHODS: Cr-Co, Cr-Ni and Pd-Ag alloys were used for this study. Each metal supported porcelain consisted of 30 specimens of 10 for 7, 9 and 11 firing each. Disc-shaped specimens 10 mm diameter and 3 mm thickness were formed by melting alloys with a propane-oxygen flame and casted with a centrifuge casting machine and then with the porcelain veneer fired onto the metal alloys. Corrosion tests were performed in quintuplicate for each alloy (after repeated porcelain firing) in Fusayama artificial saliva solution (pH = 5) in a low thermal-expansion borosilicate glass cell. Tamhane and Sheffe test was used to compare corrosion differences in the results after repeated firings and among 7, 9 and 11 firing for each alloy. The probability level for statistical significance was set at α=0.05. RESULTS: The corrosion resistance was higher (30 mV), in case of 7 times firing (Commercial). On the other hand, it was lower in case of 11 times firing (5 mV) (P<.05). CONCLUSION: Repeated firings decreased corrosion resistance of Pd-Ag, Cr-Co and Cr-Ni alloys. The Pd-Ag alloy exhibited little corrosion in in vitro tests. The Cr-Ni alloy exhibited higher corrosion resistance than Cr-Co alloys in in vitro tests.

Effect of different palatal vault shapes on the dimensional stability of glass fiber-reinforced heat-polymerized acrylic resin denture base material.

OBJECTIVE: The aim of this study was to determine the effect of different palatal vault shapes on the dimensional stability of a glass fiber reinforced heat polymerized acrylic resin denture base material. METHODS: Three edentulous maxilla with shallow, deep and medium shaped palatal vaults were selected and elastomeric impressions were obtained. A maxillary cast with four reference points (A, B, C, and D) was prepared to serve as control. Point (A) was marked in the anterior midline of the edentulous ridge in the incisive papillary region, points (B) and (C) were marked in the right and left posterior midlines of the edentulous ridge in the second molar regions, and point (D) was marked in the posterior palatal midline near the fovea palatina media (Figure 2). To determine linear dimensional changes, distances between four reference points (A-B, A-C, A-D and B-C) were initially measured with a metal gauge accurate within 0.1 mm under a binocular stereo light microscope and data (mm) were recorded. RESULTS: No significant difference of interfacial distance was found in sagittal and frontal sections measured 24 h after polymerization and after 30 days of water storage in any of experimental groups (P>.05). Significant difference of linear dimension were found in all experimental groups (P<.01) between measurements made 24 h after polymerization of specimens and 30 days after water storage. CONCLUSION: Palatal vault shape and fiber impregnation into the acrylic resin bases did not affect the magnitude of interfacial gaps between the bases and the stone cast surfaces.

Effects of six surface treatment methods on the surface roughness of a low-fusing and an ultra low-fusing feldspathic ceramic material.

PURPOSE: The purpose of this in vitro study was to determine the effects of six surface treatment methods on the surface roughness of two feldspathic ceramic materials. MATERIALS AND METHODS: One hundred twenty metal discs were cast (Remanium CS). A low-fusing feldspathic ceramic (Vita Omega 900) was fired onto 60 metal discs, and an ultra low-fusing feldspathic ceramic (Finesse) was fired onto the other 60 metal discs. Six surface treatment methods were selected: (1) autoglazing (AUG), (2) overglazing (OVG), (3) polishing (POL), (4) fine diamond disc grinding + polishing + autoglazing (FDPA), (5) coarse diamond disc grinding + polishing + autoglazing (CDPA), (6) polishing + autoglazing (PA). Omega specimens were assigned to six experimental groups representing six surface treatment methods (Om-AUG, Om-OVG, Om-POL, Om-FDPA, Om-CDPA, Om-PA) (n = 10). Finesse specimens were also assigned to six experimental groups (Fn-AUG, Fn-OVG, Fn-POL, Fn-FDPA, Fn-CDPA, Fn-PA) (n = 10). Treated ceramic surfaces were examined by means of profilometry and transmission electron microscopy. RESULTS: In Omega groups mean roughness values ranged as follows: group Om-AUG = Om-POL > Om-OVG > Om-CDPA = Om-FDPA > Om-PA (p < 0.001). No significant difference was found between groups Om-AUG/Om-POL and Om-CDPA/Om-FDPA (p > 0.05). In Finesse groups mean roughness values ranged as follows: Fn-CDPA > Fn-FDPA = Fn-AUG = Fn-POL = Fn-OVG > Fn-PA (p < 0.001). No significant difference was found between Fn-FDPA, Fn-AUG, Fn- POL and Fn-OVG (p > 0.05). CONCLUSIONS: For both ceramic types, the smoothest surfaces were obtained with polishing prior to autoglazing. Diamond disc grinding prior to polishing and autoglazing (Fn-FDPA, Fn-CDPA) displayed the roughest surfaces in ultra low-fusing ceramic (Finesse). Autoglazing alone and polishing displayed the roughest surfaces in low-fusing ceramic material (Om-AUG, Om-POL).

Three-dimensional finite element stress analysis of different core materials in maxillary implant-supported fixed partial dentures.

OBJECTIVES: The purpose of this study was to evaluate compressive and tensile stress values and patterns on implant-supported all-ceramic restorations applied in maxillary partially edentulous cases by utilizing the 3-dimensional (3-D) finite element stress analysis. METHOD AND MATERIALS: Two different 3-D finite element designs representing a maxillary implant-supported fixed partial denture (from maxillary canine to second premolar) were constructed with 3 different core materials (Inceram-Zirconia, IPS 2 disilicate glass-ceramic, cobalt-chromium). In the first design, the cross-sectional connector areas of the dentures were constructed to be 3.5 3 3.5 mm. In the second design, the cross-sectional areas were decreased to 2 3 2 mm. A load of 550 N was applied in oblique direction onto the pontic. RESULTS: The compressive and tensile stress levels obtained in the second design were higher than the first one for all materials. The compressive and tensile stresses were higher when the loads were directly applied onto the cores and the framework than when they were applied onto the porcelain sets. The cross-sectional connector area between the abutment and the pontic component has a great effect on the success of all-ceramic implant-supported fixed partial dentures. CONCLUSIONS: All 3 materials seem to have sufficient characteristic strength for 3-unit posterior implant-supported fixed partial dentures. Only the tensile stress value obtained for IPS 2 disilicate glass core material in the second design was higher than the material's characteristic strength value when the load was applied directly onto the core.

Effects of precementation desensitizing laser treatment and conventional desensitizing agents on crown retention.

This study aimed to compare the effect of precementation desensitizing laser treatment and conventional desensitizing agents on crown retention. Crowns were fabricated for 50 molar teeth, and specimens were assigned to 5 groups based on treatment method: untreated control group (CON), laser group (LAS), sodium fluoride group (FLU), Oxagel oxalate group (OXA), and Gluma primer group (GLU). All crowns were luted with glass-ionomer cement. Tensile force was applied for crown dislodgement. Recorded forces and calculated retentive strengths were as follows: CON (261 N) > LAS (223 N) = FLU (208 N) > GLU (161 N) = OXA (147 N) (P < .05). The differences in force magnitudes between all groups were significant (P < .05), except for LAS versus FLU and GLU versus OXA. The retention decrease was 15% for LAS, 20% for FLU, 38% for GLU, and 44% for OXA. Laser treatment had a less negative effect on retention for crowns luted with glass-ionomer cement than the other treatment modalities, and it may be a more suitable desensitization method if crown retention can be moderately sacrificed.

Esthetic rehabilitation of bilateral geminated teeth: a case report.

Geminated teeth are the consequences of developmental anomalies leading to the eruption of joined elements. According to current definitions, gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. Clinical experience shows, however that diagnosis can be complicated due to superimposed anomalies. This report describes a unique case of bilateral gemination of permanent maxillary central incisors. The esthetic rehabilitation of the geminated incisors accomplished utilizing all ceramic crowns. It is important that in these types of cases, reaching to the available esthetics and avoiding the complication of caries and periodontal problems with prosthetic application is satisfactory.

The effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced acrylic resin denture base material on oral epithelial cells and fibroblasts.

Acrylic resin dentures may have cytotoxic effects on oral soft tissues. However, there is sparse data about the cytotoxic effect of fibre-reinforced acrylic resin denture base materials. The purpose of this in vitro study was to determine the effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced heat-polymerized acrylic resin denture base material on oral epithelial cells and fibroblasts. One hundred acrylic resin discs were assigned to five experimental groups (n = 20). One of the groups did not include any fibre. Two groups consisted of silane and monomer treated glass fibres (Vetrolex) impregnated into acrylic resin (QC-20) discs. The other two groups consisted of silane and monomer treated carbon fibres (Type Tenox J, HTA). Untreated cell culture was used as positive control. The human oral epithelial cell line and buccal fibroblast cultures were exposed to test specimens. The cytotoxicity of the test materials was determined by succinic dehydrogenase activity (MTT method) after 24 and 72 h exposures. Data were analysed with a statistical software program (SPSSFW, 9.0). A one-way analysis of variance (anova) test and Bonferroni test were used for the comparisons between the groups. All statistical tests were performed at the 0.95 confidence level (P < 0.05). After 24 and 72 h incubation, cell viability percentages of all experimental groups showed significant decrease according to the positive control cell culture. Fibroblastic cell viability percentages of silane and monomer treated fibre-reinforced groups were lower than the unreinforced group. Cell viability of monomer-treated groups displayed the lowest percentages. Elapsed incubation time decreased epithelial cell viability in silane-treated groups. Fibroblastic cell viability was not influenced by elapsed time except the unreinforced group.

Resistance of three new esthetic post-and-core systems to compressive loading.

STATEMENT OF PROBLEM: Despite their esthetic properties, the fracture resistance of newly introduced esthetic post-and-core systems has not been studied, restricting clinical use. PURPOSE: The purpose of this study was to determine and compare the fracture resistances of 3 recently introduced esthetic post-and-core systems with a cast metal post and core using a clinically related test method. MATERIAL AND METHODS: Forty recently extracted caries-free maxillary central incisors were selected, sectioned, and their roots endodontically treated. The roots were then embedded in acrylic resin blocks and assigned to 4 experimental groups (n = 10). The cast metal (Wiron 99) post-and-core group (CMDC) served as the control. Three experimental groups consisted of a stainless steel post/composite-resin (Charisma) core group (SCOM), zirconium dioxide post/composite-resin (Charisma) core group (ZCOM), and zirconium dioxide post/ceramic (Cosmopost) core group (ZCER). The post spaces were prepared, posts were seated, cores were formed, and 40 post-and-core foundations were cemented into the roots. Following thermal cycling (5000 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds), a compressive load was applied to the inclined surface of each specimen at a 130-degree angle to the specimen long axes in a universal testing machine at a crosshead speed of 1 mm/min until failure occurred. Force to failure (N) was recorded. Data were analyzed with a 1-way analysis of variance and Bonferroni tests to determine the difference between the groups (alpha=.05). For pairwise comparisons among group mean values, P < .0083 indicated statistical significance and established the overall confidence level at 95%. RESULTS: Groups CMDC (738.6 N +/- 10.2) and ZCER (710.2 N +/- 5.3) exhibited the highest resistance to fracture. The ZCOM group showed the lowest fracture resistance (450.3 N +/- 5.7). The fracture resistance of the SCOM group (565 N +/- 7.2) was lower than the CMDC and ZCER groups, and higher than the ZCOM group. The differences among the groups were significant (P < .001) except for CMDC and ZCER (P < .016). CONCLUSION: Within the limitations of this study, the cast metal post/core and zirconia post/ceramic core foundations were found to be more fracture resistant than the zirconia post/composite-resin core and stainless steel post/composite-resin core foundations. Aside from its desirable esthetic properties, the zirconia post/ceramic core combination demonstrated high resistance to fracture.

Effects of different retraction medicaments on gingival tissue.

OBJECTIVE: Exposure of the gingival sulcus and control of hemorrhage are prerequisites to the treatment of cervical lesions and improving the quality of impressions prior to fabricating indirect restorations. Gingival retraction cords saturated with different medicaments are widely used for this purpose. However, the long-term effects of the chemicals in gingival tissues are not clear. The purpose of this study was to compare the histopathologic effects of 2 different retraction solutions in gingival tissue. METHODS AND MATERIALS: In this in vivo study, a solution of 10% aluminum chloride and a solution of 15.5% ferric sulfate were used as retraction medicament in dogs. The saturated cords were allowed to remain in the gingival sulcus of the dogs for 3 minutes. After the removal of the cords, gingival biopsies were taken at 30 minutes, 24 hours, 7 days, and 12 days. For all specimens, histologic evaluation was performed by light microscopy to determine the degree of epithelial loss, alteration of the connective tissue, and inflammation. RESULTS: Histopathologic examination of gingival tissue revealed that the ferric sulfate solution caused significant changes in gingival tissues at the beginning. However, the tissue returned to its normal histologic appearance at the end of day 12. CONCLUSION: The results of this study revealed that the biologic effects of ferric sulfate solution are more satisfactory than aluminum chloride solution. However, both medicaments are reliable and can be used in gingival retraction.

Barrier membrane and bone graft treatments of dehiscence-type defect at existing implant: a case report.

Dehiscence-type bony defects may occur after implant application because of microbial action as well as of biomechanical and occlusal overload. The aim of the treatment of a periimplant defect is to arrest the progression of the bone loss and to achieve a maintainable site for the implant. In these situations, barrier membranes and bone graft materials can be used to achieve complete bone healing around dental implants. Bone regeneration is possible in a periimplant bony defect of a functioning implant if the proper surgical technique is utilized and the etiologic cause is eradicated. This study presents the surgical coverage of a periimplant bony defect around an implant that was inserted 7 years ago. The surgical correction was made using a barrier membrane in conjunction with bone graft materials. A follow-up of 6 months seemed to reveal radiographic bone regeneration.

The three-dimensional finite element analysis of fixed bridge restoration supported by the combination of teeth and osseointegrated implants.

This study investigated the designs of osseointegrated prostheses in cases of free-end partial edentulism using comparative stress interpreted with the three-dimensional finite element method. Three free-end fixed osseointegrated prostheses models with various connection designs (i.e., rigidly connected to an abutment tooth and an implant, rigidly connected to an implant and two abutment teeth, and rigidly connected to an implant and three abutment teeth) were studied. The stress values of the three models loaded with vertical, buccolingual, and linguobuccal directions at 30 degrees angled to vertical axis forces were analyzed. When the fixed partial denture was connected to the three natural abutment teeth and an implant, the lowest levels of stress in the bone were noted.