Francisco Rivera-Hidalgo

Influence of three membrane types on healing of bone defects

OBJECTIVES To determine and compare osseous regeneration associated with three guided tissue regeneration membrane types (expanded polytetrafluoroethylene, dense polytetrafluoroethylene, and an absorbable polylactic acid/citric acid ester base) and removal forces required for expanded and dense polytetrafluoroethylene membranes. STUDY DESIGN Bilateral osseous defects were created in 30 adult rat calvaria; one defect was covered with a test membrane and the other received no membrane (control). After 2 or 4 weeks, forces required for membrane removal from the tissues were electronically determined, and the calvaria removed and decalcified. Sections through the defects were stained and evaluated electronically and microscopically. Data were analyzed statistically. RESULTS Microscopic evaluation with Mann-Whitney U test revealed that dense polytetrafluoroethylene was associated with significantly greater bone formation than expanded polytetrafluoroethylene (p = 0.02) at 2 weeks and absorbable polylactic acid/citric acid ester base (p = 0.004) at 4 weeks. Electronic evaluation of the linear degree of fill with one way ANOVA and Tukeys test found no significant difference (p > 0.05) among the experimental or the control groups. In addition, the Mann-Whitney U test indicated that removal forces required for dense polytetrafluoroethylene were significantly less than for expanded polytetrafluoroethylene (p = 0.003). CONCLUSIONS The use of dense polytetrafluoroethylene as a membrane barrier deserves further investigation as it allows osseous regeneration, it is easier to remove from healing soft tissues, and it is inexpensive. A study with larger sample sizes should be conducted.

Kahweol and cafestol: Inhibitors of hamster buccal pouch carcinogenesis

Kahweol and cafestol, two compounds extracted from green coffee beans, were tested for cancer chemopreventive activity. For the experiment, 60 hamsters were divided into three equal groups and placed on one of three diets. The animals in Group I received a normal diet, whereas the animals in Groups II and III received the same diet supplemented with a 50:50 mixture of kahweol and cafestol. The content of the kahweol and cafestol mixture in these two diets was 0.2 g/kg of food (Group II) and 2.0 g/kg of food (Group III). After the hamsters adjusted to their respective diets, 16 hamsters from each group were selected. The left buccal pouches of these animals were painted three times weekly with a 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. The 12 remaining hamsters were used as controls. The left buccal pouches of these animals were painted three times weekly with mineral oil. After 13 weeks (39 applications) the hamsters were killed. Multiple tumors were common in animals treated with DMBA; however, the animals receiving kahweol and cafestol in the diet (2 g/kg of food) exhibited a 35% reduction in tumor burden. Further comparisons between Groups I and III showed that this reduction in tumor burden was due to a decrease in tumor number. The results for Group II were inconclusive. Some reduction in tumor number was found, but this was offset by an increase in the size of the tumors.

A Comparative Study of Root Coverage Using Two Different Acellular Dermal Matrix Products

BACKGROUND Gingival recession remains an important problem in dental esthetics. A new dermal matrix material has been introduced, but its effectiveness has not been studied and compared to current dermal matrix material. The aim of this study is to compare the healing associated with a coronally advanced flap for root coverage in areas of localized tissue recession when using Alloderm (ADM) and Puros Dermis (PDM). METHODS A split-mouth design was used for this study, with 52 contralateral sites in 14 patients with Miller Class I or III facial tissue recession. Twenty-six sites were treated with coronally advanced flap using PDM, and 26 sites were treated with coronally advanced flap using ADM, all followed for 6 months. Clinical measurements of vertical recession, keratinized tissue, probing depths, and attachment levels were made initially, at 3 months, and at 6 months. RESULTS Both groups had significant improvement in the amount of recession coverage with means of 2.83 mm for the PDM and 3.13 mm for the ADM. The percentage of root coverage was 81.4% for the PDM and 83.4% for the ADM; differences between the materials were not statistically significant. CONCLUSIONS Based on the results of this study, there was no statistical or clinical difference in the amount of root coverage, probing depth, or keratinized tissue in coronally advanced flaps for root coverage with either of the two acellular dermal matrix materials. Both materials were successful in achieving root coverage.

Inhibition of hamster buccal pouch carcinogenesis by green coffee beans

Forty female Syrian Golden hamsters were divided into two equal groups and placed on one of two diets. The hamsters in Group I received a normal chow, and the animals in Group II were given the same chow supplemented with powdered green coffee beans (20%). After the hamsters adjusted to the diets, 16 animals from each group were selected. The right buccal pouch of each of these hamsters was painted three times weekly with a 0.5% solution of 7, 12-dimethylbenz(a)anthracene (DMBA) in heavy mineral oil. The eight remaining animals, four in each group, served as controls and were treated three times weekly with heavy mineral oil. After a total of 50 treatments (16 1/2 weeks), the hamsters were killed. The animals receiving green coffee beans exhibited a significant delay in the development of DMBA-induced carcinogenesis of the buccal pouch mucosa, as determined by both visual and histologic examination.

A Comparison of the Periodontal Status in Patients With Mucous Membrane Pemphigoid: A 5-Year Follow-Up

BACKGROUND Mucous membrane pemphigoid (MMP) is a heterogeneous group of blistering autoimmune disorders of unknown etiology. Intraoral manifestations of MMP feature the formation of vesiculobullous lesions that eventually rupture, leading to pseudomembrane-covered, irregularly-shaped ulcerations. The presence of these often painful oral lesions may hinder oral hygiene efforts resulting in increased plaque accumulation and may increase the risk of developing periodontal disease. The purpose of this study was to evaluate the changes in periodontal status in patients with MMP after a period of 5 years. METHODS Twenty patients, 10 diagnosed with MMP and 10 controls matched for age, gender, and smoking history, were chosen to participate in a study evaluating their periodontal status. Parameters evaluated included the plaque index, gingival index, bleeding index, probing depths, recession, clinical attachment level, mobility, furcation involvement, number of missing teeth, and periodontitis. Data from the same MMP and control patients were available for comparison from an identical baseline evaluation performed 5 years earlier. RESULTS Patients with MMP exhibited a statistically significant higher gingival index and amount of lingual gingival recession at both time periods compared to controls. Both groups exhibited statistically significant increases in attachment loss and facial/lingual recession, but the difference in change between groups was not statistically significant. CONCLUSIONS The results of this study suggest that patients diagnosed with MMP appear to be no more at risk than controls matched for age, gender, and smoking history in developing or having an increased progression of periodontal disease.

A comparative study of root defect coverage using an acellular dermal matrix with and without a recombinant human platelet-derived growth factor.

BACKGROUND The objective of this case series is to compare root defect coverage results and healing responses of bilateral recession defects treated with acellular dermal matrix (ADM) with and without recombinant human platelet-derived growth factor (rhPDGF). METHODS Seventeen patients with 40 bilateral gingival recession defects were compared. Each defect was ≥2 mm and treated with ADM and a coronally advanced flap. Using split-mouth design, the control-side ADM was hydrated in sterile saline, whereas the test-side ADM was hydrated in rhPDGF. The patients were evaluated at 1 week, 1 month, 3 months, and 6 months. Standardized measurements were taken preoperatively at 3 and 6 months. Healing was clinically assessed at 1 week and 1 month post-surgically. RESULTS Both test and control groups showed significant gain in root defect coverage over the 6-month period for all individuals, with the test group showing a 69.0% gain and the control group showing a 76.7% gain. Patients divided into Miller Class I and Class III defects were also found to have a significant gain in root defect coverage over 6 months. The test group showed 84.1% gain, and the control group showed 84.7% gain for Miller Class I defects. For Miller Class III defects, the test group showed 51.5% gain, and the control group showed a 60.8% gain. One week after surgery, 35% of the test group showed better healing, whereas 15% of the control group showed better healing. One month after surgery, 20% of the test group showed better healing, whereas 15% of the control group showed better healing. CONCLUSION Based on the results of this case series, there were no statistically or clinically significant differences in root defect coverage, keratinized tissue, clinical attachment level, or clinical healing for treatment of root recession with a coronally advanced flap and ADM with and without rhPDGF.

3-Methoxybenzamide, A Possible Initiator for DMBA-Induced Carcinogenesis

During the last few years this laboratory has formulated a hypothesis (Fig. 1) linking nicotinamide, NAD, and poly(ADP-ribose) polymerase to carcinogenesis. The factors that have led to the development of this hypothesis are as follows: (i) The fact that poly(ADP-ribose) polymerase utilizes NAD as a substrate to form poly(ADP-ribose) (1). (ii) The ability of this nuclear enzyme to respond to damage in DNA (2–4). (iii) Evidence (5, 6) indicating that poly(ADP-ribose) polymerase has a role in DNA repair, (iv) The fact that carcinogens damage DNA and the possibility that this damage is the driving force in carcinogenesis (7, 8).

Videoscope-Assisted Minimally Invasive Periodontal Surgery: One-Year Outcome and Patient Morbidity.

The aim of this study was to report the 1-year clinical outcomes from videoscope-assisted minimally invasive surgery (V-MIS). A sample of 18 patients having sites with residual pocket probing depth (PPD) of at least 5 mm and 2 mm loss in clinical attachment level (CAL) following initial nonsurgical therapy were treated with V-MIS. At 12 months postsurgery, there was a statistically significant improvement (P < .001) in mean PPD (4.11 ± 0.98 mm) and CAL (4.58 ± 1.19 mm) in all surgical sites. A mean improvement in soft tissue height (0.48 ± 0.65 mm, P = .006) was also observed. In most cases, patients reported no postoperative discomfort. The improvements associated with V-MIS appear to be favorable when compared with previously reported results of periodontal regenerative surgery. The lack of postsurgical recession following V-MIS has not been reported with traditional regenerative surgery.

Videoscope Assisted Minimally Invasive Surgery (VMIS): 36-Month Results

BACKGROUND Clinical outcomes from videoscope assisted minimally invasive surgery (VMIS) at 36 to 58 months are reported. METHODS Fourteen patients having sites with residual probing depth (PD) of at least 5 mm and 2 mm loss of clinical attachment level (CAL) after initial non-surgical therapy were treated with VMIS. RESULTS At 36 months or greater post-surgery there was a statistically significant improvement (P <0.001) in mean PD and CAL (PD: 3.80 ± 1.18 mm, CAL: 4.16 ± 1.18 mm) in all surgical sites compared with baseline. There was a mean improvement in soft tissue height (0.36 ± 0.64 mm, P = 0.03). In most cases, patients reported no postoperative discomfort. CONCLUSIONS Improvements from VMIS appear to be favorable when compared with previously reported results of periodontal regenerative surgery. All improvements were stable over time. The lack of post-surgical recession after VMIS has not been reported with traditional regenerative surgery.