Biomedical subjects

Henry Greenwell

Publications and source records attributed to Henry Greenwell.

11 recordsLinked to original sources

PubMed2006

Correlation between carotid area calcifications and periodontitis: a retrospective study of digital panoramic radiographic findings in pretreatment cancer patients.

OBJECTIVES: The objective of this study was to examine the prevalence of carotid area calcifications retrospectively detected on digital panoramic radiographs of pretreatment cancer subjects, and to correlate the finding of such calcifications with radiographic evidence of periodontal bone loss in the same subjects. STUDY DESIGN: Digital panoramic radiographs of 201 subjects were evaluated for calcifications projected in the carotid artery bifurcation area as well as for alveolar bone loss as a result of periodontal disease. Inclusion criteria were unobscured carotid artery bifurcation regions bilaterally and sufficient index teeth present with a definable cemento-enamel junction and alveolar crest. Radiographs were independently observed for carotid area calcifications and for periodontal status. Image enhancements permitted for detection of calcifications projected in the carotid area included window/level, inverse, and emboss. Periodontal measurements were made on index teeth using proprietary imaging software and a mouse-driven measurement algorithm. A 3-factor analysis of variance was performed with 3 between-subjects comparisons. Percentage of bone loss was the dependent variable. Independent variables were age, subject sex, and the presence or absence of carotid area calcifications. RESULTS: Differences measured in percentage of bone loss between sexes were not statistically significant. While bone loss did increase with age, comparison of the mean bone loss of each age category revealed no statistical significance. There was a highly significant correlation between carotid artery area calcifications visible on panoramic radiographs and percent alveolar bone loss. Radiographs showing unilateral and bilateral calcifications had a mean percent bone loss of 24.2% +/- 12.6% and 25.7% +/- 13.0% respectively, compared to those with no calcification at 10.4% +/- 9.9%. CONCLUSIONS: Nearly 1 in 4 subjects in this study evidenced calcifications projected in the carotid bifurcation region. The finding of such calcifications was significantly related to the calculated percentage of alveolar bone loss.

Age Factors↗

PubMed2005

Oral reconstructive and corrective considerations in periodontal therapy.

This paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. It is intended to provide information for the dental profession and other interested parties. The purpose of this paper is to provide a general overview of oral reconstructive and corrective procedures used in periodontal therapy. It is not intended to be a comprehensive review of this subject.

Connective Tissue↗

PubMed2005

Periodontal regeneration.

Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

Absorbable Implants↗

PubMed2005

Complete root coverage at multiple sites using an acellular dermal matrix allograft.

This study reports results of root coverage treatment with a coronally positioned flap and an acellular dermal matrix allograft. The same protocol was followed as in a previous university study to determine if the results could be duplicated in a private practice setting. Complete root coverage was obtained on most defects. Use of an acellular dermal matrix allograft avoided the postoperative morbidity associated with harvesting palatal connective tissue. The unlimited supply of the allograft allowed extended flaps to achieve multiple site root coverage, which proved to be a practical and predictable procedure in these cases.

Biocompatible Materials↗

PubMed2004

The clinical effect of acellular dermal matrix on gingival thickness and root coverage compared to coronally positioned flap alone.

BACKGROUND: The primary aim of this randomized, controlled, blinded, clinical investigation was to compare the coronally positioned flap (CPF) plus an acellular dermal matrix (ADM) allograft to CPF alone to determine their effect on gingival thickness and percent root coverage. METHODS: Twenty-four subjects with one Miller Class I or II buccal recession defect of > or = 3 mm were treated with a CPF plus ADM or a CPF alone. Multiple additional recession sites were treated with the same flap procedure, and all sites were studied for 6 months. Tissue thickness was measured at the sulcus base and at the mucogingival junction of all teeth, with an SDM ultrasonic gingival thickness meter. RESULTS: For the ADM sites, mean initial recession of 3.46 mm was reduced to 0.04 mm for defect coverage of 3.42 mm or 99% (P < 0.05). For the CPF group, mean initial recession of 3.27 mm was reduced to 1.08 mm for defect coverage of 2.19 mm or 67% (P < 0.05). The difference between ADM and CPF groups was statistically significant (P < 0.05). Marginal soft-tissue thickness was increased by 0.40 mm (P < 0.05) for the ADM group, whereas the CPF group remained essentially unchanged. Keratinized tissue was increased for the ADM group by 0.81 mm (P < 0.05), whereas the CPF group increased by 0.33 mm (P > 0.05). No additional root coverage was gained due to creeping attachment between 2 and 6 months for either group. CONCLUSIONS: Treatment with a CPF plus an ADM allograft significantly increased gingival thickness when compared with a CPF alone. Recession defect coverage was significantly improved with the use of ADM.

Adult↗

PubMed2004

Superficial-layer split-thickness flap for maximal flap release and coronal positioning: a surgical technique.

The aim of this report is to describe the superficial-layer split-thickness flap, which provides maximal flap release and mobilization for coronal positioning. The traditional split-thickness flap technique dissects following the contour of the buccal alveolar plate, leaving a periosteal layer on the osseous surface, while the muscular layer remains with the flap. This limits flap mobilization and can lead to flap retraction during healing because of muscle pull from lip and cheek movement. The superficial-layer split-thickness flap technique dissects following the contour of the external surface of the flap, toward the lip or cheek, and separates the epithelium and connective tissue from the underlying muscular and periosteal layers, which remain attached to bone. The advantages of this technique are: (1) the extreme flap release that allows complete, passive flap coverage for virtually all root coverage, ridge preservation, and ridge augmentation procedures; and (2) the absence of muscle pull during healing, which prevents flap retraction and promotes more rapid union of flap margins. Four cases are presented to demonstrate the flap technique and healing advantages.

Alveolar Ridge Augmentation↗

PubMed2003

Ridge preservation with freeze-dried bone allograft and a collagen membrane compared to extraction alone for implant site development: a clinical and histologic study in humans.

BACKGROUND: Tooth extraction typically leads to loss of ridge width and height. The primary aim of this 6-month randomized, controlled, blinded, clinical study was to determine whether ridge preservation would prevent post-extraction resorptive changes as assessed by clinical and histologic parameters. METHODS: Twenty-four patients, 10 males and 14 females, aged 28 to 76 (mean 51.5 +/- 13.6), requiring a non-molar extraction and delayed implant placement were randomly selected to receive either extraction alone (EXT) or ridge preservation (RP) using tetracycline hydrated freeze-dried bone allograft (FDBA) and a collagen membrane. A replaced flap, which did not completely cover the sockets, was used. Following extraction, horizontal and vertical ridge dimensions were determined using a modified digital caliper and an acrylic stent, respectively. Prior to implant placement, a 2.7 x 6.0 mm trephine core was obtained and preserved in formalin for histologic analysis. RESULTS: The width of the RP group decreased from 9.2 +/- 1.2 mm to 8.0 +/- 1.4 mm (P<0.05), while the width of the EXT group decreased from 9.1 +/- 1.0 mm to 6.4 +/- 2.2 mm (P<0.05), a difference of 1.6 mm. Both the EXT and RP groups lost ridge width, although an improved result was obtained in the RP group. Most of the resorption occurred from the buccal; maxillary sites lost more width than mandibular sites. The vertical change for the RP group was a gain of 1.3 +/- 2.0 mm versus a loss of 0.9 +/- 1.6 mm for the EXT group (P<0.05), a height difference of 2.2 mm. Histologic analysis revealed more bone in the RP group: about 65 +/- 10% versus 54 +/- 12% in the EXT group. The RP group included both vital bone (28%) and non-vital (37%) FDBA fragments. CONCLUSIONS: Ridge preservation using FDBA and a collagen membrane improved ridge height and width dimensions when compared to extraction alone. These dimensions may be more suitable for implant placement, especially in areas where loss of ridge height would compromise the esthetic result. The quantity of bone observed on histologic analysis was slightly greater in preservation sites, although these sites included both vital and non-vital bone. The most predictable maintenance of ridge width, height, and position was achieved when a ridge preservation procedure was employed.

Adult↗

PubMed2003

Comparison of porous and non-porous teflon membranes plus a xenograft in the treatment of vertical osseous defects: a clinical reentry study.

BACKGROUND: The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects. METHODS: Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner. RESULTS: There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill. CONCLUSION: Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

Adult↗

PubMed2002

Emerging concepts in periodontal therapy.

Conventional periodontal therapy consists of mechanical scaling and root planing, and surgical treatment. This is still the mainstay of periodontal treatment. Adjunctive antimicrobial treatments, both systemic and local delivery, are becoming more sophisticated and useful in the treatment of recurrent periodontitis. Also very promising are adjunctive treatments that modulate the host response and decrease levels of destructive pro-inflammatory cytokines or matrix metalloproteinases. Smoking is a major risk factor for periodontitis and has a profound impact on the progression of periodontal bone and attachment loss. In the interest of improved periodontal health patients should be encouraged to stop smoking. Finally bacterial endotoxins that stimulate the release of pro-inflammatory cytokines can have systemic effects and may lead to pre-term, low birthweight babies, and cardiovascular diseases such as atherosclerosis, myocardial infarction and stroke. Health professionals need to be cognisant of the effect dental health can have on systemic diseases and refer for treatment when appropriate to ensure that optimum oral and systemic health is achieved for their patients.

Anti-Infective Agents↗

PubMed2002

Are cardiac transplant patients more likely to have periodontitis? A case record study.

In several large epidemiological studies chronic periodontitis has been implicated as an additional risk factor, independent of other risk factors, for the development of ischaemic heart disease. The underlying mechanism is thought to be a localised infection giving rise to an inflammatory host response, and some experimental data agree with this hypothesis. Recently, however, some studies have questioned the post dated relationship between the two diseases. The current case-record study was undertaken to evaluate the prevalence of chronic periodontitis and the severity of such periodontal disease in a heart transplant population, assuming the latter represented a relatively severely compromised cardiovascular patient population. The study demonstrated that 76% of the patients had various degrees of periodontal disease prior to undergoing a heart transplant. Thus, it is possible that a relationship between cardiovascular disease and periodontal disease exists, but further, large intervention studies will be needed to confirm such a conclusion.

Adolescent↗

PubMedDate not supplied

Comparison of an allograft in an experimental putty carrier and a bovine-derived xenograft used in ridge preservation: a clinical and histologic study in humans.

PURPOSE: The aim of this randomized, controlled, blinded clinical study was to compare ridge dimensions and histologic characteristics of ridges preserved with 2 different graft materials. MATERIALS AND METHODS: Twenty-four subjects, each requiring a nonmolar extraction and delayed implant placement, were randomly selected to receive ridge preservation treatment with either an allograft in an experimental putty carrier plus a calcium sulfate barrier (PUT) or a bovine-derived xenograft (BDX) plus a collagen membrane. Horizontal and vertical ridge dimensions were determined using a digital caliper and a template. At 4 months postextraction, a trephine core was obtained for histologic analysis. RESULTS: The average ridge width decreased by 0.50 mm for both groups (P < .05). The midbuccal vertical change for the PUT group was a loss of 0.3+/-0.7 mm versus a gain of 0.7+/-1.2 mm for the BDX group, a difference of 1.0 mm (P > .05). Histologic analysis revealed vital bone in the PUT group of about 61%+/-9% versus 26%+/-20% for the BDX group (P < .05). DISCUSSION: Greater vital bone fill in the PUT group may be attributable to earlier and greater vascular invasion of the carrier material. The putty material was characterized by ease of handling, simple placement, and enhanced graft particle containment. CONCLUSIONS: Allograft mixed with an experimental putty carrier produced significantly more vital bone fill than did the use of a xenograft with no carrier material. Ridge width and height dimensions were similarly preserved with both graft materials.

Alveolar Bone Loss↗