Effect of Different Surface Treatments on Retention of Cement-Retained, Implant-Supported Crowns

PURPOSE: To evaluate the effect of different treatments applied to titanium implant abutment surfaces on the retention of implant-supported cement-retained crowns using resin cement. MATERIALS AND METHODS: A total of 72 titanium implant abutments were divided into six groups (n = 12 each) based on the selected surface treatments: (1) untreated; (2) airborne particle abrasion; (3) hydrogen peroxide etching; (4) atmospheric plasma; (5) chemical mechanical polishing; and (6) titanium dioxide (TiO2) nano coating. After the surface treatments, scanning electron microscopy analyses and surface roughness measurements of the abutment surfaces were performed. Seventy-two metal copings were fabricated and cemented on the abutments with dual-curing resin cement. After a thermal cycling process, crown retention was measured using a universal testing machine. The experimental results were statistically evaluated with one-way analysis of variance, Tukey honest significant difference, and Tamhane's T2 tests. RESULTS: The highest surface roughness values were obtained with the airborne-particle abrasion group (1.44 µm), which also resulted in the highest retention values (828.5 N), followed by the hydrogen peroxide-etching group (490.7 N), the atmospheric plasma group (466.5 N), the chemical mechanical polishing group (410.8 N), and the control group (382.6 N). CONCLUSION: It was determined that airborne particle abrasion, hydrogen peroxide etching, and atmospheric plasma treatments significantly increased the crown retention and that all alternative treatments, except for TiO2 nano coating, worked better than the untreated control.

Effect of Over-the-Counter Topical Agents on Denture-Induced Traumatic Lesions: A Clinical Study.

PURPOSE: To investigate the effects of over-the-counter products on the healing of denture-induced ulcerations and patients' self-reported pain. MATERIALS AND METHODS: A total of 140 patients with acute denture-induced ulcerations were randomized into seven treatment groups: denture grinding (control); topical application of corn oil gel (placebo); triester glycerol oxide gel; D-panthenol gel; D-panthenol mouthwash; L-arginine mouthwash; and hyaluronic acid gel. Healing and self-reported pain were assessed after 1, 3, and 7 days of treatment. RESULTS: The percentage of healed lesions in the mandible and maxilla after 7 days was 67% and 65%, respectively. The only significance in healing was for mandibular lesions at 3 days after application of L-arginine mouthwash; at this period, the healing rate was significantly higher than d-panthenol gel, d-panthenol mouthwash, and hyaluronic acid gel (P < .05). CONCLUSION: Denture grinding as the current protocol for acute denture-induced ulcerations should remain as the default.

Comparison of retention forces with various fabrication methods and materials in double crowns.

PURPOSE: The purpose of this study was to analyze the retention force changes and wear behaviours of double-crown systems over long-term use. MATERIALS AND METHODS: Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of 4° and 6°. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS: In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the LL-4° group (32.89 N-32.65 N), and the lowest retention force values were found in the ZA6° group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION: More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.

Distal extension mandibular removable partial denture with implant support.

This case report describes the fabrication of a distal extension removable partial denture (RPD) of a 65-year-old man with implant support. Loss of fibroelasticity of the peripheral tissues and reduced mandibular vestibular sulcular depth due to a previous surgical resection and radiotherapy at the right side were the main clinical factors that created difficulty for denture retention and stability. The fabrication of a mandibular RPD supported by anterior teeth and two bilaterally placed implants in the molar area to convert from Kennedy Class 1 design to Kennedy Class 3 implant-bounded RPD is reported. Retention and stability of the denture were improved with implant support on the distal extension site of the RPD. The common clinical problems about distally extended RPDs are lack of retention and stability due to the movement around the rotational axis. Dental implant placement to the distal edentulous site minimizes the potential dislodgement of the RPD is popular. Implant-supported RPD can be suggested as an advantageous and cost-effective treatment option for the partially edentulous patients.

Retention and surface changes of zirconia primary crowns with secondary crowns of different materials.

OBJECTIVES: To evaluate zirconia as a substitute for gold alloy in primary crowns facing secondary crowns manufactured with different materials, in terms of long-term retention force changes, wear, and phase transformation was aimed. MATERIALS AND METHODS: A total of 12 groups, each containing six samples, consisting of gold alloy primary crown-electroformed gold secondary crowns (AA), zirconia primary crown-electroformed gold secondary crowns (ZA) and zirconia primary crown-casted non-precious alloy secondary crowns (ZC) with conus angles of 0°, 2°, 4°, and 6° were evaluated. Samples were subjected to 10,000 insertion-separation cycles in artificial saliva and retention force was measured. X-ray diffraction and scanning electron microscope analysis were performed on the sample surfaces. RESULTS: The highest retention forces were obtained from ZC-0° group (72.09-71.26 N) and the lowest were obtained from ZA-4° (12.73-19.44 N) and ZA-6° (5.36-19.73 N) groups in the beginning and after 10,000 cycles, respectively. Retention force increased as the conus angle decreased. The monoclinic phase ratio of the zirconia primary crowns decreased after the experiments. No wear was observed in zirconia primary crowns except for the ZC-0° and ZC-2° groups. The use of zirconia primary crowns resulted in a less excursive retention force. CONCLUSIONS: A more predictable and less excursive retention force can be obtained using a hard and rigid primary crown material like zirconia. CLINICAL RELEVANCE: Despite a lack of knowledge about the aging of zirconia without a veneer layer in the oral environment, zirconia primary crowns are more advantageous in terms of retention force development and wear.

Multidisciplinary treatment of non-syndromic oligodontia.

Oligodontia is the agenesis of 6 or more teeth, excluding third molars. The etiology of congenital absence of teeth is believed to be rooted in heredity or developmental anomalies. The absence of teeth in patients can cause aesthetic, functional, and psychological problems, particularly if the anterior region is involved. This case report describes the multidisciplinary treatment approach toward a patient 17 years of age with non-syndromic oligodontia, with absence of 11 permanent teeth. Genetic counseling revealed non-syndromic, autosomal-recessive-linked oligodontia. The objectives of the first phase of therapy were pre-prosthetic orthodontic space opening for proper positioning of the missing teeth and correction of inter-maxillary relations, as a prerequisite for proper prosthetic restoration. The second phase of therapy was prosthetic restoration of the missing teeth and provision of occlusion with full-mouth porcelain fused to metal crowns and bridges after increasing occlusal vertical dimension by 2 mm.

Effect of post-polymerization heat-treatments on degree of conversion, leaching residual MMA and in vitro cytotoxicity of autopolymerizing acrylic repair resin.

OBJECTIVES: This study evaluated the effect of post-polymerization heat-treatments on degree of conversion (DC), residual methyl methacrylate concentration (MMA(r)) and in vitro cytotoxicity of autopolymerizing acrylic repair resin. METHODS: A total of 336 specimens were prepared by bench- and hydroflask-curing and subjected to post-polymerization heat-treatments: a) water immersion at 60°C for 30 min, b) microwaving at 500 W for 3 min, c) combined use of water immersion and microwaving d) no treatment (as control). Specimens were eluted in cell culture medium for 1, 2, 5 and 7 days. DC and MMA(r) in eluates were measured by FTIR spectrometry and HPLC, respectively. In vitro cytotoxicity of eluates on L-929 fibroblasts was determined by XTT assay. Data were statistically analyzed with Dunn's multiple comparison and Pearson correlation tests (p≤0.05). RESULTS: DC was highest (99.9%) in bench- and hydroflask-cured groups which were subjected to water immersion. At all elution periods, MMA(r) was detected in eluates of all treatment groups and were higher in bench-cured groups than hydro-flask cured groups. Cell proliferation values indicated slightly cytotoxic effect throughout 7 days; regardless of the curing method or post-polymerization treatment. The correlation between MMA(r) and cell proliferation was negative after elution of 1, 2, 5 days and was only statistically significant (p<0.05) at 5 days. At elution of 7 days, the correlation was positive with no significance. SIGNIFICANCE: Post-polymerization heat-treatment of autopolymerizing acrylic repair resin by immersion in water at 60°C for 30 min is clinically recommended to improve the DC while reducing the leaching residual MMA.

Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles.

OBJECTIVES: Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. MATERIAL AND METHODS: A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05). RESULTS: [MMA]r was significantly (p<0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. CONCLUSION: Due to reduction of leaching residual MMA concentrations, use of terminal boiling in the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects.

Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

OBJECTIVES: Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. MATERIAL AND METHODS: A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05). RESULTS: [MMA]r was significantly (p<0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. CONCLUSION: Due to reduction of leaching residual MMA concentrations, use of terminal boiling in the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects.

Flexural properties of repaired heat-polymerising acrylic resin after wetting with monomer and acetone.

OBJECTIVES: Repair strength can be improved by treating fractured surfaces of a denture. BACKGROUND: This study investigated flexural properties of heat-polymerised acrylic resin specimens repaired with auto-polymerising and visible light curing (VLC) resins after the repair surfaces were wetted with monomers or acetone. MATERIALS AND METHODS: Fifty-four specimens (65 x 10 x 2.5 mm) were prepared and 48 of them were sectioned to simulate denture fracture. Butt-joint designed repair surfaces were wetted with heat-, auto-polymerising monomers and acetone for 180 s and repaired with auto-polymerising and VLC resins. After repairs, specimens were subjected to three-point bending test and flexural strength, strain, fracture load, modulus of elasticity and deflection values were recorded. Data were analysed with Student t and LSD tests (p < or = 0.05). RESULTS: Overall flexural strength, strain, fracture load and deflection values of specimens repaired with VLC resin were significantly higher than the specimens repaired with auto-polymerising resin for all types of wetting agent (p < 0.05). Within the wetting agents, heat- and auto-polymerising monomers produced the best mechanical properties, while wetting with acetone did not provide superior effect over both monomers. CONCLUSION: In clinical use, wetting the repair surfaces may result in stronger repairs. The use of bonding agent in VLC resin repairs in combination with wetting agent results in improved flexural properties.

Oral health and inflammation in patients with end-stage renal failure.

BACKGROUND/AIMS: End-stage renal disease (ESRD) patients have an increased risk of atherosclerotic complications. In both hemodialysis (HD) patients and the general population, it has become evident that inflammation plays an important role in the pathogenesis of atherosclerotic complications. Oral and dental problems in ESRD patients could be an important source of inflammation, thus treatment of these problems is important to protect these patients from potential infections. The decayed, missing, and filled teeth (DMFT) index is an indicator of oral and dental health status. Our aim was to analyze and compare salivary flow rate (SFR), salivary pH (SpH), salivary buffering capacity (SBC), and DMFT index and plaque index (PI) values in PD patients to HD patients and healthy controls (C) and establish the relationship between these parameters and C-reactive protein (CRP). METHODS: 76 PD patients, 100 HD patients, and 111 Cs were included in the study. SFR (milliliters/minute) was measured in stimulated whole saliva, SpH was measured using the Merck indicator, and SBC was measured according to the method of Ericsson: 1 mL whole saliva was added to 3 mL 0.005 N HCl and a stream of air was passed through this mixture for 20 minutes. Finally, DMFT index and PI values were calculated. RESULTS: No statistically significant differences were found in age or gender distribution among PD, HD, and C groups. There was also no significant difference in time on dialysis between PD and HD groups. SFR was significantly lower in the PD and HD groups than in the C group (1.30 +/- 0.83 and 0.70 +/- 0.32 vs 1.64 +/- 0.45 mL/min) and lower in the HD than in the PD group (p < 0.001). SpH (8.35 +/- 0.43 and 8.12 +/- 0.74 vs 7.16 +/- 0.76) and SBC (7.39 +/- 0.47 and 6.82 +/- 0.70 vs 5.08 +/- 0.73) were significantly higher in the PD and HD groups than in the C group and higher in the PD than in the HD group (p < 0.05 and p < 0.001 respectively). The numbers of filled teeth were significantly higher in the PD than in the HD and C groups (p < 0.001). DMFT index was significantly higher in the PD than in the HD group (p < 0.001). Finally, PI values were significantly higher in the PD and HD groups than in the C group (p < 0.001) and higher in the HD than in the PD group, although this was not statistically significant. In the present study, we also found higher CRP values in HD than in PD patients and a positive correlation between CRP and PI values in PD patients. CONCLUSIONS: PD patients have higher SFR, SpH, and SBC values than HD patients; however, higher DMFT index and higher numbers of filled teeth were observed in PD patients. Compared to healthy controls, patients on dialysis had worse dental and periodontal findings, which might have a role in microinflammation in this group of patients.

Effect of educational level on oral health in peritoneal and hemodialysis patients.

Background. In previous studies, the oral and dental health statuses were compared in hemodialysis (HD) and peritoneal dialysis (PD) patients without taking into account the effect of educational levels on oral health. Hence we aimed to make a comparison of these parameters based upon the subjects educational levels. Patients and Methods. 76 PD (33 males, 43 females-mean age: 44 +/- 12 years) and 100 HD (56 males, 44 females-mean age: 46 +/- 14 years) patients were included. The number of decayed, missing and filled teeth were detected, DMFT index was calculated and plaque index (PI) values were assessed. Results. Significantly higher numbers of filled teeth (P < .001) and lower PI values (P < .01) in the PD group were detected with higher educational levels, whereas no significance was detected in the HD group. Higher DMFT index values were assessed in the lower educated and high school levels in PD than HD patients (P < .05). Higher numbers of filled teeth (P < .05) were detected in the secondary school level in PD patients. This difference was even more significant in the high school level (P < .001). Conclusion. We assume that PD patients, who were found to be in a higher educational level, are more caring for their oral health as compared to HD patients.

Interim removable partial dentures: two case reports.

For the partially edentulous patient, an interim denture can provide acceptable short-term function and esthetics by replacing missing teeth and tissues until a definitive restoration can be performed. This article presents two cases that required interim removable partial dentures to maintain function, phonation, and esthetics until clinical conditions allowed for the fabrication of definitive dentures.

Influence of polymerization method, curing process, and length of time of storage in water on the residual methyl methacrylate content in dental acrylic resins.

This study compared the influence of different polymerization methods (heat, auto-, and microwave energy), different curing processes (in the case of heat- and autopolymerized specimens), and length of storage of the polymerized specimens in distilled water at 37 degrees C on the residual methyl methacrylate (MMA) content in dental acrylic resin specimens. Residual MMA of 120 resin specimens were measured using high-performance liquid chromatography. For the heat-polymerized resins, the lowest residual MMA content was obtained when they were given a long-term terminal boil and then stored in the distilled water for at least 1 day. For the autopolymerized resins, the lowest residual MMA content was obtained when they were additionally cured in water at 60 degrees C and then stored in the distilled water at least 1 day. For the microwave-polymerized resins, the lowest residual MMA content was obtained when they were stored in the distilled water at least 1 month. The lowest overall residual MMA content was obtained from heat-polymerized specimens that were given a long-term terminal boil cure and then stored in the distilled water at least 1 day. Different polymerization methods and curing processes have different effects on residual MMA content. It is thus shown that storing a dental acrylic resin specimen in distilled water at 37 degrees C is a simple but effective method of reducing its residual MMA content.

Effects of water storage of E-glass fiber reinforced denture base polymers on residual methyl methacrylate content.

This study investigated the effect of water storage on residual methyl methacrylate (MMA) content of continuous E-glass fiber (Wetrotex International) reinforced denture base polymers. Heat-polymerization (short- and long-term boiling and conventional curing cycle using Meliodent), autopolymerization (processed in air at room temperature and in water at 60 degrees C with the use of Meliodent Rapid Repair), and microwave-polymerization (3 min at 500 W with the use of Acron MC) were employed. The residual MMA contents of 120 specimens were analyzed by high-performance liquid chromatography at deflasking (control) and after water (37 degrees C) storage of 1 day, 1 week, and 1 month. Bonferroni's pairwise comparison test was used for statistical analysis. Significant reduction were determined only in the long-term terminal boiled heat-polymerized test group at the end of 1 day (p < 0.01), 1 week (p < 0.05) and also 1 month of water storage (p < 0.01). Significant reduction in autopolymerized test groups started even after 1 week of water storage (p < 0.05). Microwave-polymerized test groups did not show a significant residual MMA reduction in all time intervals (p > 0.05). The polymerization methods and cycles applied to the glass fiber reinforced denture base polymers influence both the content and the reduction of residual MMA after water storage.

Effect of glass fibre reinforcement on residual methyl methacrylate content of denture base polymers.

OBJECTIVES: Residual methyl methacrylate (MMA) content in unreinforced and in glass fibre reinforced, heat-polymerized (long- and short-term terminal boiled and conventionally) autopolymerized (at room temperature and in water at 60 degrees C) and microwave-polymerized (3min at 500W) denture base polymers after processing were compared. METHODS: Ten specimens were prepared for each curing cycle (five unreinforced and five reinforced) adding up to a total of 60. Residual MMA content was determined using high-performance liquid chromatography. Data were analysed with one-way ANOVA followed by Tukey HSD and Paired Samples tests. RESULTS: For unreinforced and reinforced groups; residual MMA content succesively ranked from lowest to highest in; long- and short-term terminal boiled heat-polymerized, microwave-polymerized, autopolymerized specimens processed in water at 60 degrees C and conventionally heat- and autopolymerized specimens processed at room temperature. Generally residual MMA was found more in glass fibre reinforced test groups than unreinforced groups. However, when reinforced residual MMA increased significantly in long- and short-term terminal boiled heat- (P<0.05) and microwave-polymerized test groups (P<0.01). CONCLUSIONS: Although this increase was significant, lowest residual MMA content was found succesively in reinforced long- and short-term terminal boiled heat-polymerized and microwave-polymerized like in unreinforced groups.

Stimulated salivary flow rate in chronic hemodialysis patients.

BACKGROUND: Reduced salivary flow has been reported in patients undergoing hemodialysis (HD) treatment. Our aim was to investigate the most important factors associated with stimulated salivary flow rate (ssfr) in chronic HD patients. METHODS: Fifty HD patients (27 F, 23 M, mean age 46. 7 +/- 13.2 years) were divided into two groups according to the duration of HD treatment as those receiving HD therapy less than or equal to (group I) or those more than (group II) 24 months. Fasting blood samples were obtained to determine hepatitis B and C serology, and biochemical and hematological parameters before a HD session. After prestimulation with a standard weight paraffin wax, stimulated saliva was collected in the HD patients and control group (23 F, 25 M, mean age 45.7 +/- 19.1 years) and the flow rate was expressed as ml/min. RESULTS: Both HD groups consisted of 25 patients. There was no significant difference between the two HD groups other than serum alkaline phosphatase (ALP) levels and presence of HCV. The ssfr was decreased than controls in both groups (0.8 +/- 0.6 and 0.7 +/- 0.4, respectively, vs. 1.5 +/- 0.5 ml/min) and it did not correlate with any parameter. Smoking had a positive effect on ssfr in all groups. CONCLUSION: Although the salivary flow rate decreased significantly in chronic HD patients, the duration of therapy displayed no effect on the salivary changes in HD patients, but smoking increased ssfr.