Attitudes of dentists in British Columbia toward removable prosthodontics

A survey was sent to all registered dentists in British Columbia regarding their training and attitudes in removable prosthodontics. A reasonable number of the questionnaires were returned so that general comments can be made about perceived needs and suggestions to improve training and practice.There was a clear feeling among the dentists surveyed that dental school training had not prepared them adequately for the clinical practice of removable prosthodontics. It was suggested that increased emphasis be placed on both didactic and clinical instruction. Increasing the number and quality of faculty was frequently mentioned.There was a perceived need for integrated instruction with other disciplines and increased emphasis on total patient care, including areas such as nutrition and psychology.In general, removable prosthodontics was felt to be an important area of continuing education. Short courses, study groups, and programs at meetings were perceived to be desirable and necessary.Prosthodontic care was felt to be a significant need of the population. Inadequate training in dental school would be a disservice to both the practitioners and their patients. Access to high-quality dental care is an important aspect of the quality of life, and removable prosthodontics is an integral and important part of dental care.     

Ultrastructural features of the verruciform xanthoma

The verruciform xanthoma, a rare lesion of the oral cavity, was studied by light and electron microscopy. The major cell type associated with the lesion was shown to contain appreciable amounts of lipid and was characterized as a macrophage. It was characteristic of the endothelial cells associated with subepithelial capillaries to exhibit multiple basal laminae. A rather unusual observation was the migration of lipid-filled cells into the stratum germinativum of the overlying epithelium.     

Metal ceramic compatibility: a review of the literature

Metal ceramic restorations are popular in restorative dentistry. Although bonding mechanisms are understood, defining compatibility of alloy and porcelain has been illusive. Chemical compatibility implies a chemical bond between ceramic and alloy that resists stresses resulting from thermal and mechanical incompatibility without compromising esthetics. Research has attempted to predict and test compatibility with varying degrees of success. Despite the success of metal ceramic restorations over the years, compatibility remains undefined without standardized testing procedures. For optimal results, the dentist should communicate with experienced laboratory personnel to meet the specific needs of the patient.     

A mandibular advancement device reduces sleep disordered breathing in patients with congestive heart failure

Sleep disordered breathing (SDB) including obstructive and central sleep apnoea/hypopnoea as well as periodic breathing (PB) is common and is believed to increase risk for mortality in patients with congestive heart failure (CHF). Mandibular advancement device (MAD) has widely been recommended for treatment of obstructive sleep apnoea but the method has never been investigated for treatment of SDB in the patients with CHF. The aim with the present study was to examine the effect of MAD intervention on SDB in patients with CHF. The study included 17 male patients, aged 68.4+/-5.7 (mean+/-SD) with stable, mild to moderate CHF due to left ventricular systolic dysfunction and with SDB, expressed as apnoea/hypopnoea index (AHI) > or = 10. The SDB was examined during a single night using an unattended, portable polysomnographic device in the patients home, prior to and following intervention with a individually adjusted MAD. The SDB was evaluated by calculating AHI, PB expressed as the percentage of the total registration time, oxygen desaturation index (ODI) and snoring time. The AHI was reduced by MAD intervention from 25.1+/-9.4 to 14.7+/-9.7 (p=0.003). ODI reduced from 21.1+/-9.0 to 10.5+/-7.8 (p=0.007) and snoring time decreased from 53+/-111 to 18+/-47 seconds (p=0.02). PB was reduced from 55.7+/-25.6 to 40.4+/-26.4 per cent without statistical significance. In conclusion, the MAD intervention may be a feasible method for reducing SDB in patients with stable, mild to moderate CHF and left ventricular systolic dysfunction.     

Studies of the oxidation of a hydroxychromium(III)-[hydrotrispyrazoylborate]pyrazolyl complex

The oxidation of the Cr^III hydroxy complex, Tp^tBu,MeCr(pz^′)(OH), 1, (Tp^tBu,Me=hydrotris(3-tert-butyl-5-methylpyrazolyl)borate; pz^′=3-tert-butyl-5-methylpyrazolyl anion) was studied in methylene chloride at a glassy carbon electrode. There are two oxidation peaks, Ia and IIa, that are totally irreversible and Cr^IV oxo complex 2 is the product at both peaks. Peak Ia grows with respect to IIa as the scan rate is reduced and the voltammograms were quantitatively accounted for by a CE_irr mechanism involving two interconverting forms of 1, 1a giving peak Ia and 1b giving peak IIa. The reduction of 2 is detected on the return scan along with a small amount of 3 that arises from hydrogen-atom abstraction by 2 from hydrogen-atom donors in the medium. The processes giving rise to peaks Ia and IIa have the characteristics of dissociative electron- transfer reactions. It is suggested that they may be concerted electron-proton transfer reactions. It is speculated that the postulated minor form of 1, 1a, may be an isomer having axial OH rather than the equatorial OH found in the favored isomer, 1b.     

Preformed acrylic cranial implants using fused deposition modeling: a clinical report

Fabrication of acrylic cranial implants by conventional methods of moulage and mold formation may be difficult when the margin of the defect cannot be accurately detected. Three-dimensional anatomic models built by fused deposition modeling can serve as templates for the fabrication of custom acrylic implants for large or complicated cranial defects. Virtual mirror imaging of the contralateral nondefect side can facilitate the restoration of symmetry in appearance-sensitive areas. This clinical report presents a method for the fabrication of cranial implants for 2 patients using anatomic modeling technology.     

Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed partial dentures, and extraction without replacement: a systematic review

STATEMENT OF PROBLEM: Dentists and patients are regularly confronted by a difficult treatment question: should a tooth be saved through root canal treatment and restoration (RCT), be extracted without any tooth replacement, be replaced with a fixed partial denture (FPD) or an implant-supported single crown (ISC)? PURPOSE: The purpose of this systematic review was to compare the outcomes, benefits, and harms of endodontic care and restoration compared to extraction and placement of ISCs, FPDs, or extraction without tooth replacement. MATERIAL AND METHODS: Searches performed in MEDLINE, Cochrane, and EMBASE databases were enriched by hand searches, citation mining, and expert recommendation. Evidence tables were developed following quality and inclusion criteria assessment. Pooled and weighted mean success and survival rates, with associated confidence intervals, were calculated for single implant crowns, fixed partial dentures, and initial nonsurgical root canal treatments. Data related to extraction without tooth replacement and psychosocial outcomes were evaluated by a narrative review due to literature limitations. RESULTS: The 143 selected studies varied considerably in design, success definition, assessment methods, operator type, and sample size. Direct comparison of treatment types was extremely rare. Limited psychosocial data revealed the traumatic effect of loss of visible teeth. Economic data were largely absent. Success rates for ISCs were higher than for RCTs and FPDs, respectively; however, success criteria differed greatly among treatment types, rendering direct comparison of success rates futile. Long-term survival rates for ISCs and RCTs were similar and superior to those for FPDs. CONCLUSIONS: Lack of comparative studies with similar outcomes criteria with comparable time intervals limited comparison of these treatments. ISC and RCT treatments resulted in superior long-term survival, compared to FPDs. Limited data suggested that extraction without replacement resulted in inferior psychosocial outcomes compared to alternatives. Long-term, prospective clinical trials with large sample sizes and clearly defined outcomes criteria are needed.     

The effect of multiple uses of disposable diamond burs on restoration leakage

BACKGROUND: The authors tested the clinical longevity of disposable diamond burs. They cut a series of five preparations and assessed the leakage after restoring the tooth. METHODS: The authors prepared 10 teeth for Class V restorations, and used a new disposable diamond bur for each tooth. The burs were used to cut preparations in extra teeth before being used to prepare a second series of 10 teeth (third use). The authors then cut preparations in extra teeth before preparing a third set of 10 teeth (fifth use). They removed existing restorations in a second group of 30 teeth and extended the preparations using the same regimen of one, three and five bur uses. All preparations were etched and conditioned, and the teeth were restored with resin-based composite. Using a 20-volt direct-current power source and a stainless-steel counter electrode, the authors measured the leakage electrochemically in 1.0 percent sodium chloride for 30 days. RESULTS: Freshly prepared and restored teeth leaked less than reprepared teeth. Leakage was similar for the first and third uses of the bur, but was far greater for the fifth use (P < .01). The previously restored teeth that were cut with the first- and third-use burs behaved the same, but the third-use bur caused more leakage than the fifth-use bur (P < .01). CONCLUSIONS: Reuse of disposable burs can affect leakage behavior. With new preparations, use of a disposable bur to cut more than three preparations increased leakage. For teeth that were reprepared and restored, greater leakage occurred than it did with new preparations, although repeated use of a bur may reduce leakage. CLINICAL IMPLICATIONS: Disposable diamond burs may cut preparations in up to three teeth before adversely affecting leakage behavior. Restoration removal and repreparation of teeth results in greater leakage than that with freshly prepared teeth.