Ronald G. Verrett

Analyzing the Etiology of an Extremely Worn Dentition

Patients requiring extensive restorative care frequently exhibit significant loss of tooth structure. Specific clinical findings in an extremely worn dentition may vary widely and are often confusing. Severe wear can result from a mechanical cause, a chemical cause, or a combination of causes. The location of the wear, the accompanying symptoms and signs, and information gained from the patient interview are essential components in determining the etiology. A diagnostic decision tree facilitates a systematic analysis and diagnosis of dental wear.

The effect of sprue attachment design on castability and porosity

Sprue attachment design is an important and controversial variable that can affect casting characteristics of castability and porosity. Four sprue attachment designs--straight, flared, abrupt constriction, and gradual constriction--were investigated. Standardized wax copings simulating complete veneer metal ceramic crowns with knife-edge margins were sculpted on refractory investment dies, sprued, invested, and cast with Olympia alloy. The specimens were embedded, sectioned, and polished. Castability was analyzed by measuring the width of the cast meniscus of the margins. The margin widths of the flared and the straight sprue attachment groups were significantly less than the abrupt or gradual constriction attachment group (p less than 0.05). Photomicrographs revealed discernible differences in the relative quantity and location of porosity in the sprue-coping junctions. The straight and flared sprue attachment groups were less porous than the abrupt or gradual constriction groups (p less than 0.01). Flared and straight sprue attachments optimized castability and minimized porosity.

Investigating the Association Between Obstructive Sleep Apnea and Periodontitis

BACKGROUND Obstructive sleep apnea (OSA) is a sleep disorder characterized by disruptions of normal sleep architecture. Chronic periodontitis is a chronic disease of the periodontium that elicits a general inflammatory response to local dental plaque. It has been suggested that periodontal disease may increase in severity with increasingly severe OSA because both disease entities share common inflammatory pathways, acting synergistically to alter the host response. The aim of this study is to analyze the association between severity of OSA and the prevalence/severity of periodontitis. METHODS One hundred patients from a large veterans administration sleep study center (n = 26 normal, n = 21 mild, n = 19 moderate, n = 34 severe) diagnosed with an overnight polysomnogram underwent a comprehensive periodontal examination. Periodontal parameters measured included the following: 1) mean periodontal probing depth (PD); 2) clinical attachment level (CAL); 3) gingival recession; and 4) percentage of sites with bleeding on probing, plaque, PD ≥5 mm, and CAL ≥3 mm. RESULTS Seventy-three percent of the sampled population had moderate/severe periodontal disease. χ(2) analyses revealed no significant differences in the prevalence of periodontal disease between the apnea-hypopnea index (AHI) groups, with a negligible Spearman correlation coefficient of 0.246 between AHI severity and periodontal disease severity categories. Analysis of covariance indicated a significant association between AHI severity categories and percentage of sites with plaque, after adjusting for age. Multivariable logistic regression analysis predicting moderate/severe periodontitis with AHI score, age, and smoking status indicated a significant association with age (P = 0.028) but no significant association with the other two predictors. CONCLUSION OSA was not significantly associated with the prevalence of moderate/severe periodontitis and the periodontal parameters examined, except percentage plaque.

Marginal Gap of Milled versus Cast Gold Restorations.

PURPOSE This in vitro study evaluated and compared the vertical marginal gap of cast and milled full coverage gold copings using two margin designs (chamfer and chamfer bevel) before and after fitting adjustments. MATERIALS AND METHODS Ten impressions were made of two metal master dies (one chamfer margin, one chamfer-bevel margin) and poured twice in Type IV stone. The 20 subsequent casts with 40 dies were split into four groups (n = 10); cast gold bevel, cast gold chamfer, milled gold bevel, and milled gold chamfer groups. The cast specimens received approximately 40 μm die relief no closer than 1 mm from the finish line. Cast copings were hand waxed, cast in a high noble gold alloy, chemically divested, and the sprues were removed. For milled gold copings, casts were scanned and copings designed using 3shape D900 scanner and software. Parameters were set to approximate analog fabrication (cement gap = 0.01 mm; extra cement gap = 0.04 mm, drill radius = 0.65 mm). Copings were milled from the same high noble alloy. All copings were seated on their respective master die in a custom scanning jig and measured using a measuring microscope at 90× (60 measurements per specimen, 15 per surface). Following initial measurements, all copings were adjusted on stone dies. The number of adjustment cycles was recorded and post-adjustment measurements were made using the same method. Data were analyzed using independent and paired t-tests. RESULTS Milled gold copings with a beveled margin (11.7 ± 20.4 μm) had a significantly (p < 0.05) smaller marginal gap than cast gold copings with a beveled margin (43.6 ± 46.8 μm) after adjustment. Cast gold copings with a chamfer margin (22.7 ± 24.7 μm) had a significantly (p < 0.05) smaller marginal gap than milled gold copings with a chamfer margin (27.9 ± 31.6 μm) following adjustments. Adjustments significantly decreased marginal gap for both cast groups (p < 0.05) and the milled chamfer bevel group (p < 0.05) but had no significant effect on the milled chamfer group. CONCLUSIONS Within the limitations of this study, results indicate that gold restorations milled with the tested parameters provide a vertical marginal gap that is an acceptable alternative to traditional gold crown casting techniques.

Immediate Restoration of Single Tapered Implants with Nonoccluding Provisional Crowns: A 5-Year Clinical Prospective Study

BACKGROUND Dental literature has limited number of publications regarding long-term outcome data of immediate restoration of single missing teeth with an implant-supported provisional crown. PURPOSE This 5-year study evaluated hard and soft tissue responses to the immediate placement of single implant-supported provisional crowns. MATERIALS AND METHODS Twenty patients received one dental implant restored immediately with a provisional acrylic resin screw-retained crown. Crestal bone loss was evaluated from standardized periapical radiographs collected at 3-month intervals for the first 21 months followed by a 5-year evaluation. Historical controls acquired from available dental literature were used for comparison. RESULTS One implant failed within 2 months of surgical placement, presenting with pain and mobility. The remaining implants demonstrated no infection, pain, or radiolucencies. Nineteen implants were clinically immobile, osseointegrated, and asymptomatic at 21 months. At 5 years, one patient died, three patients were noncompliant, and 15 implants were evaluated as functional. Mean bone loss (MBL) at 1 year and 21 months was approximately 0.5 ± 0.5 mm and 0.70 ± 0.26 mm at 5 years. There was no statistically significant difference between MBLs at p < 0.05. CONCLUSIONS Immediate provisionalization of single dental implants compares favorably with conventional loading protocols. Long-term data suggest that immediate provisionalization of single dental implants is a viable treatment option.

Immediate restoration of single tapered implants with nonoccluding provisional crowns

BACKGROUND Dental literature has limited number of publications regarding long-term outcome data of immediate restoration of single missing teeth with an implant-supported provisional crown. PURPOSE This 5-year study evaluated hard and soft tissue responses to the immediate placement of single implant-supported provisional crowns. MATERIALS AND METHODS Twenty patients received one dental implant restored immediately with a provisional acrylic resin screw-retained crown. Crestal bone loss was evaluated from standardized periapical radiographs collected at 3-month intervals for the first 21 months followed by a 5-year evaluation. Historical controls acquired from available dental literature were used for comparison. RESULTS One implant failed within 2 months of surgical placement, presenting with pain and mobility. The remaining implants demonstrated no infection, pain, or radiolucencies. Nineteen implants were clinically immobile, osseointegrated, and asymptomatic at 21 months. At 5 years, one patient died, three patients were noncompliant, and 15 implants were evaluated as functional. Mean bone loss (MBL) at 1 year and 21 months was approximately 0.5 ± 0.5 mm and 0.70 ± 0.26 mm at 5 years. There was no statistically significant difference between MBLs at p < 0.05. CONCLUSIONS Immediate provisionalization of single dental implants compares favorably with conventional loading protocols. Long-term data suggest that immediate provisionalization of single dental implants is a viable treatment option.

Evaluation of a Novel Device for Measuring Patient Compliance with Oral Appliances in the Treatment of Obstructive Sleep Apnea

PURPOSE The purpose of this study was to evaluate a novel intraoral monitor for measuring patient compliance of oral appliances for the treatment of obstructive sleep apnea. MATERIALS AND METHODS A clinical trial was conducted to compare objective recording by an intraoral compliance monitor and self-reporting by participants using a mandibular repositioning device (MRD). Ten participants were fitted with a Thornton Adjustable Positioner (TAP III) with an embedded compliance monitor. The participants were asked to wear the test appliance for seven nights and to record their usage of the appliance and any adverse effects in a treatment journal. The data were downloaded to a dedicated computer using radio-frequency identification (RFID) technology, and the information was compared to the data in the participants journal. RESULTS The mean objective wearing time, as detected by the compliance monitor, was found to be 6.6 ± 1.6 hours/night. The mean subjective wearing time, as recorded by the participants, was 6.5 ± 1.5 hours/night. The correlation between subjective and objective times was 0.9985. The use of the test appliance by this sample population was 68.7% with a range of 24% to 100%. Participants reported a range of adverse outcomes related to the MRD consistent with those reported in the literature and were found to be transient in nature. CONCLUSIONS This study supports previously reported usage times and adverse outcomes. The compliance monitor showed a very high linear correlation between subjective and objective data, validating its use in future compliance studies.

Influence of Veneering Fabrication Techniques and Gas-Phase Fluorination on Bond Strength between Zirconia and Veneering Ceramics

PURPOSE Porcelain chipping has been one of the main problems of porcelain-fused-to-zirconia restorations. This study evaluates the bond strengths of layered, pressed, and adhesively bonded porcelain to yttria-stabilized zirconia substrates that have undergone traditional preparation or gas-phase fluorination. MATERIALS AND METHODS A three-point bending test was used to evaluate the bond strength of the porcelain and zirconia interface. Sixty-six specimens were prepared (n = 11) following ISO 9693 and loaded until failure using an Instron testing machine. One-half of the zirconia substrates received gas phase fluorination treatment before veneering application. Three porcelain veneering methods were evaluated: layered, pressed, and adhesively bonded porcelain. Bond strength results were interpreted using a two-way ANOVA and a Bonferroni multiple comparisons test. Statistical significance was set at α = 0.05. RESULTS ANOVA revealed a statistically significant effect of the veneering fabrication methods. No main effect was observed regarding the surface treatment to the zirconia. There was a significant effect related to the veneering method used to apply porcelain to zirconia. For untreated zirconia, layered porcelain had a significantly higher flexural strength compared to pressed or bonded, while pressed and bonded porcelains were not significantly different from one another. For zirconia specimens receiving fluorination treatment, both layered and pressed porcelains had significantly higher bond strengths than adhesively bonded porcelain. In addition, fluorinated pressed porcelain was not statistically different from the control layered or fluorinated layered porcelain. CONCLUSION The choice of veneering fabrication technique was critical when evaluating the zirconia to porcelain interfacial bond strength. Bonded porcelain to zirconia had a lower flexural strength than layered or pressed porcelain, regardless of zirconia surface treatment. In addition, fluorination had an effect on the bond strength of pressed porcelain.

Comparison of implant and provisional placement protocols in sinus-augmented bone: a preliminary report.

PURPOSE To evaluate preliminary data on clinical outcomes associated with timing of placement of single implant-supported provisional crowns and implants in augmented bone. MATERIALS AND METHODS Twenty patients underwent sinus elevation bone grafting followed by a 6-month healing period before implant placement and immediate placement of a provisional crown (group [G] 1); 20 patients received sinus elevation bone grafting at the time of implant placement and immediate placement of a provisional crown (G2); 20 patients required no bone augmentation before implant placement and immediate placement of a provisional crown (G3); and 20 patients received sinus elevation bone grafting followed by a 6-month healing period before implant placement followed by a 6-month healing period before restoration (G4). The height of the crestal bone was measured and recorded to determine mean bone changes, and success rates were determined. RESULTS Mean bone level comparisons were made between G2 and G3, G2 and G4, and G3 and G4. No statistically significant differences were found between the groups (P < .05). G1 was discontinued based on the initial results: two implants did not meet the 35-Ncm insertion test, and one implant failed within 1 month after implant placement. The 1-year implant survival rates were 86% (n = 12/14), 95% (n = 19/20), and 100% (n = 16/16) for G2, G3, and G4, respectively. Differences in survival rates between the groups were not statistically significant (P < .05). CONCLUSION Implant survival is affected by the timing of sinus augmentation and implant placement in relation to the timing of crown placement. Implants that were restored immediately regardless of the timing of bone augmentation showed greater failure rates than implants in augmented bone with delayed restoration protocols or those that were restored immediately in sites without bone augmentation. Neither the timing of loading nor timing of implant placement in relation to bone augmentation surgery affected mean bone loss.

Customizing a nasal CPAP mask using a silicone elastomer.

Nasal continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). Airway obstruction is prevented by delivering air at a constant pressure via a nasal mask worn during sleep. Small nares may cause difficulty in wearing even the smallest standard nasal mask, with wear resulting in discomfort and air leaks. This article describes a method for fabricating a custom nasal CPAP mask using maxillofacial prosthodontic laboratory techniques.