Biomedical subjects

T Howard Howell

Publications and source records attributed to T Howard Howell.

4 recordsLinked to original sources

PubMed2005

Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction socket augmentation.

BACKGROUND: Conventional dentoalveolar osseous reconstruction often involves the use of grafting materials with or without barrier membranes. The purpose of this study was to evaluate the efficacy of bone induction for the placement of dental implants by two concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered on a bioabsorbable collagen sponge (ACS) compared to placebo (ACS alone) and no treatment in a human buccal wall defect model following tooth extraction. METHODS: Eighty patients requiring local alveolar ridge augmentation for buccal wall defects (> or =50% buccal bone loss of the extraction socket) of the maxillary teeth (bicuspids forward) immediately following tooth extraction were enrolled. Two sequential cohorts of 40 patients each were randomized in a double-masked manner to receive 0.75 mg/ml or 1.50 mg/ml rhBMP-2/ACS, placebo (ACS alone), or no treatment in a 2:1:1 ratio. Efficacy was assessed by evaluating the amount of bone induction, the adequacy of the alveolar bone volume to support an endosseous dental implant, and the need for a secondary augmentation. RESULTS: Assessment of the alveolar bone indicated that patients treated with 1.50 mg/ml rhBMP-2/ACS had significantly greater bone augmentation compared to controls (P < or =0.05). The adequacy of bone for the placement of a dental implant was approximately twice as great in the rhBMP-2/ACS groups compared to no treatment or placebo. In addition, bone density and histology revealed no differences between newly induced and native bone. CONCLUSION: The data from this randomized, masked, placebo-controlled multicenter clinical study demonstrated that the novel combination of rhBMP-2 and a commonly utilized collagen sponge had a striking effect on de novo osseous formation for the placement of dental implants.

Absorbable Implants↗

PubMed2004

Problem-based learning and research at the Harvard School of Dental Medicine: a ten-year follow-up.

Dental students at the Harvard School of Dental Medicine (HSDM) are required to pursue and complete research projects in order to obtain the doctor of dental medicine (D.M.D.) degree. The purpose of this study was to evaluate the effect of curriculum changes on a set of measurable outcomes related to research pursuits. This study was designed as a retrospective analysis of outcomes data from the period 1992-2002. The predictor variable was program format (non-PBL vs. PBL); the outcome variables were the percentage of students listed as authors on an IADR/AADR abstract during their tenure at HSDM and the percentage of students listed as first and/or presenting authors. Univariate statistics were computed for each class, and independent samples t-tests were used to compare the study groups with regard to our outcomes. For the majority of our outcomes, there was no statistically significant difference between the PBL and non-PBL groups, possibly due to sample size limitations. While the implementation of PBL at HSDM has not universally increased student productivity in research, it has not had an adverse effect either. It is possible that students in the PBL curriculum are nurturing other interests, such as community service, while retaining productivity in research.

Dental Research↗

PubMed2004

Measuring the efficacy of rhBMP-2 to regenerate bone: a radiographic study using a commercially available software program.

This radiographic study evaluated the efficacy of different concentrations of rhBMP-2 to regenerate bone in alveolar defects in the anterior maxilla. The study was performed using reasonably standardized CT examinations and the Simplant program. The radiographic measurements were further refined by careful standardization of the measured regions of interest. There was a statistically significant difference in bone formation between subjects treated with a concentration of 1.5 mg/mL rhBMP-2 compared with each of the other groups. There was no statistically significant difference in bone volume between any of the other groups. None of the groups showed a loss in bone volume.

Alveolar Bone Loss↗

PubMed2003

Problem-based learning: effects on standard outcomes.

Dental students at the Harvard School of Dental Medicine (HSDM) participate fully in the first two years of the curriculum with the Harvard Medical School (HMS) while also taking parallel dental classes. HSDM students were first exposed to problem-based learning (PBL) in 1987 when the "New Pathway" curriculum was introduced at HMS in the first two years of the medical school curriculum (the HSDM courses remained traditional lecture-based classes). In 1994, HSDM incorporated PBL into the first, second, and third (clinical year) year dental courses, and the curriculum shifted from a five-year curriculum to a four-year curriculum. The purpose of this study was to evaluate the effect of PBL and program length on measurable outcomes for dental education: NBDE Part I scores, attrition and graduation rates, and percentage of graduates entering postdoctoral training programs. This study was designed as a retrospective analysis of outcomes data from 1980 to 2002. Univariate linear regressions were computed for each measure against each outcome. Subsequent bivariate regression analyses revealed that the implementation of PBL has markedly affected NBDE Part I scores, graduation rates, attrition rates, entrance into postdoctoral plans, and percentage of graduates entering GPR/AEGD programs, while program length has had an effect on graduation rates, attrition rates, entrance into postdoctoral programs, and percentage of graduates entering GPR/AEGD programs. The findings of this report suggest that the implementation of PBL combined with a change in program length has been successful for all outcomes measured and that PBL alone has contributed to the rise in NBDE Part I scores among HSDM graduates.

Boston↗