The rise and fall of the Latino dentist supply in California: implications for dental education

The purpose of this study was to determine the number of Latino dentists in California, identify the schools and countries where they were educated, and compare Latino dentist demographics with that of the state's new demographics. From the 2000 California Department of Consumer Affairs list of 25,273 dentists, we identified Latino U.S. dental graduates (USDGs) by "heavily Hispanic" surnames and Latino international dental graduates (IDGs) by country and school of graduation. From the 2000 U.S. census Public Use Microdata Sample (PUMS), we described Latino dentist characteristics such as Spanish language capacity and practice location. The number of Latino dentists acquiring licenses to practice in California has fallen dramatically, by nearly 80 percent, between 1983 and 2000. This decline is not merely an affirmative action issue; it results in an issue of access. Latino dentists are far more likely to speak Spanish and be located in a heavily Latino area than non-Latino dentists. Currently, although the supply of Latino dentists is dwindling, the Latino population is growing rapidly. In California and out-of-state schools, first-year matriculation of Latino USDG must increase. Further, non-Latino dentists should be prepared and given incentives to learn Spanish and locate practices in areas of need. The reintroduction of IDG Latino dentists needs to be seriously considered.     

A histomorphogenic analysis of bone grafts augmented with adult stem cells

PURPOSE: To evaluate the influence of bone marrow aspirate added to xenograft or alloplast graft matrix scaffold to produce bone. MATERIALS: A maximum of 4 cc bone marrow was aspirated from the anterior iliac crest of 5 patients to saturate the matrix scaffold prior to bone graft. Seven graft sites evaluated included sinus lift augmentation, particulate onlay graft of the maxilla via a tunneling procedure, and particulate onlay graft of the maxilla stabilized with titanium mesh. The xenograft scaffold was either PepGen Putty (DENTSPLY Friadent CeraMed, Lakewood, CO) or C-Graft resorbable algae material (Clinician's Preference, Golden, CO). The alloplast scaffold was beta-tricalcium phosphate (either Curasan AG, Kleinostheim, Germany, or Vitoss; Malvern, PA). RESULTS: Graft sites healed for 4-7 months. Core specimens of graft sites were taken with trephine drills, and submitted for standard histologic and histomorphogenic analysis. The percentage of graft material converted into bone, percentage of vital graft matrix, percentage of unresorbed matrix, and percentage of remaining interstitial tissue were measured. After a 4-month healing of sinus-lift augmentation with C-Graft, the biopsy showed 31% bone that was 100% vital. Unresorbed graft material was 26%, and remaining interstitial material constituted 43%. Using pure phase beta-tricalcium phosphate, a 4-month core biopsy showed 40% bone that was 100% vital. Residual graft was 3% and interstitial material 57%. A sinus grafted with PepGen P-15 (DENTSPLY Friadent CeraMed) was found to be 14% bone, with 100% of that bone vital. The non-bone within the core was 36%. After a 4 1/2-month healing of bilateral sinus grafts using a nonpure phase beta-tricalcium phosphate, the percentage of the biopsy that was bone was 23% on the right side and 16% on the left side. Vital bone was 89% (right side) and 86% (left side). The core taken after 4 months of healing from the anterior maxilla particulate onlay graft with PepGen P-15 showed 32% bone, with 100% found to be vital. Non-bone within the core was 15%, and 53% was interstitial material. After 7 months of healing, a biopsy core from the maxillary ridge augmented with C-Graft was 45% newly formed bone, with 100% of the bone vital. There was no residual graft material present. DISCUSSION: Bone regeneration by cell-based strategies depends upon an understanding of the biology and potential of adult stem cells as a method of regenerating bone. CONCLUSIONS: Bone marrow aspirate containing adult stem cells when mixed with bioengineered graft materials provide a scaffold to support the proliferation, differentiation, and maturation of the stem cells, as well as facilitating angiogenesis. This article presents histological evidence that stem cells aspirated from bone marrow and transplanted onto biocompatible scaffolds can successfully regenerate bone. This new standard for bone grafting may emerge as an alternative to autogenous bone grafts.     

Conservative aesthetic techniques for discoloured teeth: 2. Microabrasion and composite

The first article in this series discussed the minimal intervention approach to discoloured teeth, starting with dental bleaching. This second article goes on to explain the technique of microabrasion and the use of direct composite techniques. CLINICAL RELEVANCE: Microabrasion and composite can provide minimally invasive treatments for discoloured teeth.     

Resazurin metabolism assay for root canal disinfectant evaluation on dual-species biofilms

Introduction

Endodontic infections are caused by polymicrobial biofilms. Therefore, novel root canal disinfectants should be evaluated not only on single-species biofilms but also on dual- or mixed-species biofilms. A simple, high-throughput assay is urgently needed for this. In this study, the application of the resazurin metabolism assay was investigated for the evaluation of a root canal disinfectant on dual-species biofilms.

Methods

Enterococcus faecalis with or without Streptococcus mutans in biofilms were formed in an active attachment biofilm model for 24 hours. Subsequently, the biofilms were treated with various concentrations of NaOCl for 1 minute. After resazurin metabolism by both organisms was confirmed, treatment efficacies using 0.0016% resazurin were evaluated.

Results

During NaOCl treatments, resazurin metabolism displays a clear dose response, not only in single-species E. faecalis (or S. mutans) biofilms but also in dual-species biofilms. Notably, the assay revealed that the resistance of dual-species biofilms to NaOCl was 30-fold higher than in single-species E. faecalis biofilms. Viability counts on a selected NaOCl treatment (0.004%) confirmed this result and showed the increased resistance of E. faecalis in dual-species biofilms.

Conclusions

Clearly, the high-throughput and low cost resazurin metabolism assay has a great potential for testing novel root canal antimicrobial agents in mixed-species biofilms.     

Examiner training and reliability in two randomized clinical trials of adult dental caries

Objectives: This report describes the training of dental examiners participating in two dental caries clinical trials and reports the inter‐ and intra‐examiner reliability scores from the initial standardization sessions. Methods: Study examiners were trained to use a modified International Caries Detection and Assessment System II system to detect the visual signs of non‐cavitated and cavitated dental caries in adult subjects. Dental caries was classified as no caries (S), non‐cavitated caries (D1), enamel caries (D2), and dentine caries (D3). Three standardization sessions involving 60 subjects and 3,604 tooth surface calls were used to calculate several measures of examiner reliability. Results: The prevalence of dental caries observed in the standardization sessions ranged from 1.4 percent to 13.5 percent of the coronal tooth surfaces examined. Overall agreement between pairs of examiners ranged from 0.88 to 0.99. An intra‐class coefficient threshold of 0.60 was surpassed for all but one examiner. Inter‐examiner unweighted kappa values were low (0.23‐0.35), but weighted kappas and the ratio of observed to maximum kappas were more encouraging (0.42‐0.83). The highest kappa values occurred for the S/D1 versus D2/D3 two‐level classification of dental caries, for which seven of the eight examiners achieved observed to maximum kappa values over 0.90. Intra‐examiner reliability was notably higher than inter‐examiner reliability for all measures and dental caries classifications employed. Conclusion: The methods and results for the initial examiner training and standardization sessions for two large clinical trials are reported. Recommendations for others planning examiner training and standardization sessions are offered.     

The fatigue life of a cobalt-chromium alloy after laser welding

The aim of this study was to investigate the fatigue life of laser welded joints in a commercially available cast cobalt-chromium alloy. Twenty rod shaped specimens (40 mm x 1.5 mm) were cast and sand blasted. Ten specimens were used as controls and the remaining ten were sectioned and repaired using a pulsed Nd: YAG laser welder. All specimens were subjected to fatigue testing (30N - 2Hz) in a controlled environment. A statistically significant difference in median fatigue life was found between as-cast and laser welded specimens (p < 0.001). Consequently, the technique may not be appropriate for repairing cobalt chromium clasps on removable partial dentures. Scanning electron microscopy indicated the presence of cracks, pores and constriction of the outer surface in the welded specimens despite 70% penetration of the weld.     

Myeloid sarcoma occurring concurrently with drug-induced gingival enlargement

BACKGROUND: Myeloid sarcoma is an extramedullary malignancy of myeloblasts. An unusual case of myeloid sarcoma presenting in the gingiva and affected by drug-induced gingival enlargement is presented. METHODS: A 63-year-old male taking amlodipine for his hypertension presented with a 3-week gingival enlargement. Although the obvious clinical impression was that of drug-induced gingival enlargement, an incisional biopsy was performed to corroborate chemical enlargement while ruling out diseases such as lymphoma and leukemia. RESULTS: Microscopic examination of the thickened gingiva revealed surface stratified squamous epithelium having needle-like rete pegs characteristic of drug-induced gingival enlargement. Beneath the surface epithelium, the fibrous tissue was virtually replaced by a dense infiltrate of malignant cells. Immunohistochemical studies were performed with CD117 and myeloperoxidase identifying the malignant cell population as myeloblasts, leading to a diagnosis of myeloid sarcoma. CONCLUSION: Myeloid sarcoma and hematopoietic malignancies must be included in a differential diagnosis of gingival enlargement until the definitive diagnosis is reached by histologic/laboratory examination.     

Chemo-mechanical dentine caries removal with Carisolv using a rotating brush.

AIM: The aim of this study was to assess the efficacy of removing dentine caries using carbide burs, Carisolv with hand instruments and Carisolv in combination with a new mechanical excavation method using a rotating brush. METHODS: 36 extracted permanent teeth, with dentine caries, were assigned into 3 groups according to caries removal technique. Caries removal was monitored by checking the properties of the dentine with a dental explorer. After embedding and sectioning (400 microm), remaining caries was assessed by using a caries detector. In microscope images (7x) of the samples, the mean stain depth of the remaining carious tissue per tooth was calculated by AnalySIS computer software. RESULTS: Four to 8 applications (mean time = 10.9 min) of Carisolv were necessary for caries removal with the new method using rotating brushes. The mean thickness of residual dentine caries by this procedure (226 microm, +/- 136) was higher than the one using Carisolv with hand instruments (57 microm, +/- 39) or carbide burs (32 microm, +/- 20). Even in areas with good access to the lesion, an unacceptable amount of residual caries was observed. CONCLUSION: Thus, it seems that Carisolv using rotating brushes does not reach the degree of caries removal reached by additional mechanical abrasion of Carisolv using hand instruments or conventional rotating carbide burs.