Non-bioabsorbable vs. bioabsorbable membrane: assessment of their clinical efficacy in guided tissue regeneration technique. A systematic review.

In a 1998 review article, Laurell and colleagues performed a meta-analysis of relevant guided tissue regeneration (GTR) articles over the previous 20 years (1). The purpose of the present research was to expand on that work, particularly searching for trends discriminating between bioabsorbable and non-bioabsorbable barriers, as well as the use of enamel matrix derivative, with respect to interproximal bony defects. The most recent periodontal journals were reviewed and a search of PubMed (National Institutes of Health) was conducted via the internet covering 1990 to the present. Forty-nine articles were found to be relevant and within established parameters. The data were analyzed using (a) a variation of the methods described in Laurell et al. (1) and (b) statistics appropriate for inter-group comparisons. In most respects, all membranes and enamel matrix derivative (EMD) delivered better outcomes, in the range of 1 to 2 mm, than open flap debridement. The use of any barrier type or EMD configuration was found to yield more Clinical Attachment Level (CAL) gain than any open flap configuration. Other than collagen without grafts versus non-bioabsorbables without grafts, no other comparison between membranes or between membranes and EMD found any significant differences (P > 0.05). GTR was confirmed to be superior to open flap debridement.

Lysophosphatidic Acid signals through specific lysophosphatidic Acid receptor subtypes to control key regenerative responses of human gingival and periodontal ligament fibroblasts.

BACKGROUND: We showed that the pluripotent platelet growth factor and mediator lysophosphatidic acid (LPA) controls key regenerative responses of human gingival fibroblasts (GFs) and periodontal ligament fibroblasts (PDLFs) and positively modulates their responses to platelet-derived growth factor (PDGF). This study determined which LPA receptor (LPAR) subtype(s) LPA signals through to stimulate mitogenic extracellular signal-regulated kinase (ERK) 1/2 signaling and chemotaxis and to elicit intracellular Ca(2+) increases in GFs and PDLFs because many healing responses are calcium-dependent. METHODS: Activation of mitogen-activated protein kinase was determined using Western blotting with an antibody to phosphorylated ERK1/2. Migration responses were measured using a microchemotaxis chamber. GF and PDLF intracellular Ca(2+) mobilization responses to multiple LPA species and LPAR subtype-specific agonists were measured by using a cell-permeable fluorescent Ca(2+) indicator dye. RESULTS: LPA stimulated ERK1/2 phosphorylation via LPA(1)(-3). For GFs, LPA(1) preferentially elicited chemotaxis, and LPA(1-3) for PDLFs, as confirmed using subtype-specific agonists. Elevation of intracellular calcium seems to be mediated through LPA(1) and LPA(3), with little, if any, contribution from LPA(2). CONCLUSIONS: To the best of our knowledge, this study provides the first evidence that LPA signals through specific LPAR subtypes to stimulate human oral fibroblast regenerative responses. These data, in conjunction with our previous findings showing that LPA modulates GF and PDLF responses to PDGF, suggest that LPA is a factor of emerging importance to oral wound healing.

Lysophosphatidic acid modulates the healing responses of human periodontal ligament fibroblasts and enhances the actions of platelet-derived growth factor.

BACKGROUND: Platelet-derived growth factor (PDGF) has been used to promote healing in many in vitro and in vivo models of periodontal regeneration. PDGF interacts extensively with lysophosphatidic acid (LPA). We recently showed that LPA modulates the responses of human gingival fibroblasts to PDGF. The objectives of this study were as follows: 1) to evaluate the basic interactions of LPA with primary human periodontal ligament fibroblasts (PDLFs) alone and with PDGF-BB for promoting PDLF growth and migration; 2) to determine the effects in an in vitro oral wound-healing model; and 3) to identify the LPA receptors (LPARs) expressed by PDLF. METHODS: PDLF regenerative responses were measured using 1 and 10 microM LPA in the absence or presence of 1 or 10 ng/ml PDGF. Cell proliferation was determined by 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and by cell counting. Migration responses were measured using a microchemotaxis chamber. PDLFs were grown to confluence on glass slides, a 3-mm-wide wound was mechanically inflicted, and wound fill on days 4, 6, and 9 was reported. PDLF LPAR expression was determined using Western blotting. RESULTS: PDLFs exhibited proliferative and chemotactic responses to LPA; these responses were enhanced when LPA and PDGF were present together. LPA plus PDGF elicited complete wound fill. PDLFs express the LPARs LPA(1), LPA(2), and LPA(3). CONCLUSIONS: To our knowledge, this study provides the first evidence that LPA stimulates human PDLF wound healing responses and interacts positively with PDGF to regulate these actions. These results suggest that LPA and its receptors play important modulatory roles in PDLF regenerative biology.

Osteoporosis: una revisión de sus implicancias odontológicas / Osteoporosis: a review of his implications dentals

El presente articulo revisa los conceptos relacionados a la enfermedad periodontal y su relación con el nivel de densidad ósea en pacientes con osteopenia y osteoporosis, incluyendo aspectos clínicos, histológicos y prescripción terapéutica asociada.

Lysophosphatidic acid modulates the regenerative responses of human gingival fibroblasts and enhances the actions of platelet-derived growth factor.

BACKGROUND: Platelet-derived growth factor (PDGF) has been used to promote healing in many in vitro and in vivo models of periodontal regeneration. PDGF is known to interact extensively with another platelet mediator, lysophosphatidic acid (LPA), to enhance regenerative responses in non-oral systems. PDGF and LPA are both liberated by platelets in the blood clot, which is known to be critical in stabilizing early periodontal wound healing. The purpose of this study was to evaluate the basic interactions of LPA with primary human gingival fibroblasts (GF) alone and with PDGF-BB for promoting GF growth and migration, as well as their effects in an in vitro oral wound-healing model. METHODS: GF regenerative responses were measured using 1 and 10 microM LPA in the absence or presence of 1 or 10 ng/ml PDGF-BB. Cell growth was determined using [3H]thymidine incorporation and cell counting. Migration responses were measured using a microchemotaxis chamber. For the in vitro wound-healing experiments, GF were grown to confluence on glass slides, and a 3 mm wide wound was mechanically inflicted. Percent wound fill on days 4, 6, and 9 was analyzed using computer-assisted histomorphometry. RESULTS: GF exhibited proliferative and chemotactic responses to LPA. These responses were synergistic when LPA and PDGF-BB were present together. LPA on its own did not stimulate statistically significant wound fill, but when combined with PDGF-BB, wound fill was equivalent to the 10% serum positive control group by day 6 (5.5-fold of negative control, [P<0.001]) and again on day 9 (6-fold of negative control, [P<0.001]). CONCLUSIONS: These studies provide the first evidence that LPA stimulates human GF regenerative responses and that it interacts positively with PDGF-BB to regulate these actions. The results suggest that LPA needs to be further investigated in the oral system as a factor that should be considered for incorporation when designing new periodontal wound-healing therapies using PDGF.

Complications associated with diabetes mellitus after guided tissue regeneration--a case report revisited.

Twelve to fourteen million individuals suffer from diabetes mellitus (DM), though the disease is undiagnosed in a large number of these people. Dentists must be aware of the signs and symptoms of DM so they can better manage the treatment of whatever dental therapy their patients with diabetes require. DM has been reclassified into type 1 and type 2, based on the individual's insulin requirements. The diabetic patient may present with, or develop, advanced periodontal disease, which may be more difficult to control because of metabolic status and commitment to dental care. This article includes a description of a type 2 diabetic who reportedly was well controlled, yet experienced complications after guided tissue regeneration. The postsurgical results were acceptable and the patient remained stable during supportive periodontal therapy. However, she became noncompliant with her dental care and converted from a type 2 to a type 1 diabetic with poor control. The case illustrates the rapid progression of periodontal disease in a side that had been successfully treated. It also discusses the interrelationships between diabetes and periodontal disease.

Osteoporosis: a review and its dental implications.

Osteoporosis is a disease that affects primarily women, but can also occur in men. It is characterized by a loss of bone mineral density (BMD), and often culminates in a fracture of the hip, wrist, and/or vertebrae. The diagnosis of osteoporosis is often made by using bone density measurements. They are often expressed in relative terms (T-scores and Z-scores); the Z-score is the number of standard deviations from the age-matched average value of healthy women. A low Z-score indicates the bone density is lower than it should be for a patient's age and sex. Osteoporosis is defined as a BMD loss of 2.5 standard deviations or more below the established mean. Osteoporosis can be treated by a variety of methods, the most common being the use of estrogen, with or without progestin or progesterone. The use of estrogen alone is referred to as estrogen replacement therapy (ERT), and the combination hormone replacement therapy (HRT). Other drugs used in the treatment of osteoporosis are the selective estrogen receptor modulators (SERMs) and the bisphosphonates. The SERMs appear to offer many of the positive benefits of estrogen with fewer adverse effects on the breast or uterus. Recently, a randomized, double blind study of nearly 3,000 women found no overall benefit in reducing heart disease for those taking estrogen. In fact, in the first year of estrogen use, heart disease was higher in this group than in those taking placebo. The relationship between systemic BMD and periodontal status has been investigated. In some patients, there is a correlation between a decrease of mandibular bone mass and tooth loss. In others, there is no such correlation. Those postmenopausal women taking HRT had greater tooth retention and a reduced likelihood of edentulism. A recent study has found no correlation between clinical attachment levels and the BMD of the lumbar spine. Many possible factors contribute to the development of osteoporosis and periodontal diseases. It is difficult to establish a direct correlation between tooth loss, bone loss, and loss of attachment resulting from periodontitis and decreased BMD associated with osteoporosis, but studies are ongoing.