Alveolar ridge resorption has long been considered an unavoidable consequence of tooth extraction and can be a significant problem in implant and restorative dentistry. Postextraction maintenance of the alveolar ridge minimizes residual ridge resorption and allows placement of an implant that satisfies both esthetic and functional criteria. Guided bone-regeneration techniques and the use of bone-replacement materials have been shown to enhance socket healing and potentially modify the resorption process. The prime indication for socket preservation is the prevention of alveolar-bone and soft-tissue collapse, which would cause unacceptable prosthesis esthetics. This review describes the rationale behind socket preservation, and the various techniques and materials used for extraction site grafting.

Periodontitis is a well-appreciated example of leukocyte-mediated bone loss and inflammation that has pathogenic features similar to those observed in other inflammatory diseases such as arthritis. Resolvins are a new family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammatory signals. Because it is now increasingly apparent that local inflammation plays a critical role in many diseases, including cardiovascular disease, atherosclerosis, and asthma, experiments were undertaken to evaluate the actions of the newly described EPA-derived Resolvin E1 (RvE1) in regulation of neutrophil tissue destruction and resolution of inflammation. The actions of an aspirin-triggered lipoxin (LX) analog and RvE1 in a human disease, localized aggressive periodontitis (LAP), were determined. Results indicate that neutrophils from LAP are refractory to anti-inflammatory molecules of the LX series, whereas LAP neutrophils respond to RvE1. In addition, RvE1 specifically binds to human neutrophils at a site that is functionally distinct from the LX receptor. Consistent with these potent actions, topical application of RvE1 in rabbit periodontitis conferred dramatic protection against inflammation induced tissue and bone loss associated with periodontitis.

Recent studies have suggested the use of drugs to modulate host response as a new approach in periodontal therapy. In this regard, the tetracycline antibiotics have been found to inhibit host-derived collagenases and other matrix metalloproteinases by a mechanism independent of the antimicrobial activity of these drugs; this effect may suppress connective tissue breakdown during periodontal disease and during a variety of medical disorders including (but not limited to) noninfected corneal ulcers, serious (sometimes life-threatening) skin-blistering diseases, rheumatoid arthritis and osteoarthritis, systemically--as well as locally--induced bone loss, and perhaps even tumor-induced angiogenesis. Two therapeutic strategies based on the host-modulating properties of tetracyclines are currently being developed: 1) the use of low-dose doxycycline (the most potent anticollagenase of commercially available tetracyclines) formulations, which do not appear to result in tetracycline side effects such as the emergence of antibiotic-resistant microorganisms; and 2) the production of a family of chemically modified tetracyclines that have lost their antimicrobial activity, but have retained their anticollagenase activity. A description of several of these compounds and a discussion of their efficacy in inhibiting collagenases in vitro and reducing tissue destruction in several animal models of periodontal and medical diseases is presented.

TEN PATIENTS WHO REQUIRED two or more anterior teeth extractions were utilized in this study. Extraction procedures were carried out with a full thickness surgical flap approach. After flap reflection, teeth were removed with a minimum of trauma to the surrounding bone. Following extraction silicone-based impression techniques were used to produce a model of the alveolar process and small metal pins were placed in the alveolus to be used as fixed points to make measurements of ridge dimensions. One socket was covered with an expanded polytetrafluoroethylene (ePTFE) barrier membrane (experimental site); the other socket was a conventional control. The soft tissue flaps were then mobilized using periosteal releasing incision and the wound closed with ePTFE mattress sutures. Six months following extraction, patients were treated with flap surgery to expose both extractions sites to remove the ePTFE membranes and to measure ridge dimensions using the pins as fixed points. Clinical and model measurements have shown statistically significant better ridge dimensions at experimental sites than at control (P < or = 0.05). Three patients with exposed membranes had similar dimensional changes as controls. Results from this study suggested that this improved technique offers a predictable alveolar ridge maintenance enhancing the bone quality for dental implant procedures and esthetic restorative dentistry.

The purpose of this study was to evaluate the clinical effectiveness of a bioabsorbable membrane made of glycolide and lactide polymers in preserving alveolar ridges following tooth extraction using a surgical technique based on the principles of guided bone regeneration. Sixteen patients requiring extractions of 2 anterior teeth or bicuspids participated in the study (split-mouth design). Following elevation of buccal and lingual full-thickness flaps and extraction of teeth, experimental sites were covered with bioabsorbable membranes; control sites did not receive any membrane. Titanium pins served as fixed reference points for measurements. Flaps were advanced in order to achieve primary closure of the surgical wound. No membrane became exposed in the course of healing. Reentry surgeries were performed at 6 months. Results showed that experimental sites presented with significantly less loss of alveolar bone height, more internal socket bone fill, and less horizontal resorption of the alveolar bone ridge. This study suggests that treatment of extraction sockets with membranes made of glycolide and lactide polymers is valuable in preserving alveolar bone in extraction sockets and preventing alveolar ridge defects.

Strontium ranelate (S12911) has previously been shown to stimulate bone formation and inhibit bone resorption in rats. To determine whether strontium ranelate affects normal bone remodeling, we studied the effect of strontium ranelate on alveolar bone in monkeys. Strontium ranelate, at dosages of 100, 275, and 750 mg/kg per day, or vehicle, were given by gavage to 31 normal adult monkeys (Macaca fascicularis)(15 males, 16 females), aged 3-4 years. Treatment for 6 months with strontium ranelate resulted in an increase in plasma strontium concentration. Histomorphometric analyses of indices of bone formation and resorption were determined in standardized areas of alveolar bone. Treatment with strontium ranelate decreased the histomorphometric indices of bone resorption (osteoclast surface and number) with a maximal significant effect at the highest dose tested. In contrast to this inhibitory effect on bone resorption, strontium ranelate maintained bone formation. Although the amount of osteoid tended to increase, strontium ranelate, even at the highest dose, had no deleterious effect on bone mineralization, as evaluated by mineral apposition rate and osteoid thickness. These findings show that strontium ranelate decreases indices of bone resorption while maintaining bone formation in the alveolar bone in monkeys.

The treatment of periodontal disease has been largely directed at the microbiological etiology. The prevention of bone loss by modulating the host response to the bacteria may be a useful adjunctive method in the management of periodontitis. Alendronate, an amino bisphosphonate, may inhibit bone loss in osteolytic diseases by altering osteoclast activity. The objective of this double-blind study was to evaluate alendronate inhibition of alveolar bone loss in the naturally occurring beagle dog model of periodontitis. Sixteen 7 to 9 year old beagles with moderate-to-severe periodontitis were studied for 6 months. The dogs were stratified into two groups based on initial periodontal severity. One group received 3.0 mg/kg alendronate weekly orally and the other group received a placebo. Silk ligatures were placed on the study teeth for the first 3 months of the study to exacerbate the periodontal destruction. Clinical data were collected for attachment level, gingival index, plaque index, and mobility at baseline and one-month intervals. Intraoral radiographs were made at baseline and at 3 and 6 months. The mandibles were processed for histology at month 6. The radiographs were analyzed by digital image analysis of the subtracted images. A statistically significant difference in bone mass (P < 0.001) was observed between the alendronate and placebo groups. The bisphosphonate had no effect on the clinical parameters of gingival inflammation or plaque. A trend toward decreased attachment loss and mobility was observed in favor of the alendronate group.(ABSTRACT TRUNCATED AT 250 WORDS)

The overall aim of this study was to examine the relationship between bone mass of the jaw and the axial skeleton. Sixty-nine subjects (age at entry: 32-64), who underwent hormone replacement therapy during the study period, participated. Bone mass of the lumbar spine was determined using dual photon absorptiometry. The jaw-bone of the posterior region of the mandible was evaluated by means of standardized long-cone radiography using individual bite-blocks. A densitometric wedge in the film holder provided a reference to quantify bone mass. From both measurements, it appeared that the bone mass of the mandible and the lumbar spine showed a moderate relationship. The present results also confirmed that estrogen replacement therapy had a positive effect on the bone mass of the mandible and the lumbar spine. Different estrogen regimens resulted in different increases in bone mass during the observation period, which was on average 5 yr.

Systemic non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce alveolar bone loss in periodontitis. This study assesses the efficacy of a topical NSAID rinse, containing ketorolac tromethamine as the active agent. Adult periodontitis patients (n = 55) were studied in this 6-month randomized, double blind, parallel, placebo and positive-controlled study. Each patient had a least 3 sites at high risk for bone loss as assessed by low dose bone scan. Groups, balanced for gender, were assigned to one of three regimens: bid ketorolac rinse (0.1%) with placebo capsule; 50 mg bid flurbiprofen capsule (positive control) with placebo rinse; or bid placebo rinse and capsule. Prophylaxes were provided every 3 months. Monthly examinations assessed safety, gingival condition, and gingival crevicular fluid PGE2. Standardized radiographs were taken at baseline and at 3 and 6 months for digital subtraction radiography. A significant loss in bone height was observed during the study period in the placebo group (-0.63 +/- 0.11; P < 0.001), but not in the flurbiprofen (-0.10 +/- 0.12; P = 0.40) or ketorolac rinse (+0.20 +/- 0.11 mm; P = 0.07) groups. Nested ANOVA revealed that ketorolac and flurbiprofen groups had less bone loss (P < 0.01) and reduced gingival crevicular fluid PGE2 levels (P < 0.03) compared to placebo. ANOVA suggests (P = 0.06) that ketorolac rinse preserved more alveolar bone than systemic flurbiprofen at the dose regimens utilized. These data indicate that ketorolac rinse may be beneficial in the treatment of adult periodontitis.

Mucoperiosteal flaps are used to access the bone and root surface in a wide range of periodontal procedures and in implant surgery. We have demonstrated that the mucoperiosteal surgical flap of the rat mandible produces a transient burst of alveolar bone resorption similar to the clinical observations in humans. This resorptive activity, when coupled with local irritation factors, may cause confined alveolar bone loss. Recently, we have demonstrated that an amino bisphosphonate, which is used in preventing systemic bone resorption in osteoporosis and other bone diseases, reduces alveolar bone resorption in the rat model when administered systemically. In this study we evaluated the effect of local delivery of the amino bisphosphonate on bone resorption associated with mucoperiosteal flaps. Following mucoperiosteal flap elevation in the premolar and molar region of the rat mandible, a surgical pellet soaked with amino bisphosphonate was locally applied on the exposed bone surface and covered by flap. The results show that local delivery of amino bisphosphonate reduces significantly alveolar bone resorption activated by mucoperiosteal flap surgery. This study suggests that local application of amino bisphosphonate can be used as an adjunct in therapy for reducing bone resorption following surgery.

Systemic metronidazole and tetracycline were compared as adjunctive agents in the treatment of localized juvenile periodontitis (LJP). 27 patients with Actinobacillus actinomycetemcomitans-positive (Aa) LJP were treated with scaling and rootplaning, control of oral hygiene and periodontal surgery if indicated. The patients were randomly divided into 3 equal groups: the 1st group had metronidazole 200 mg x 3 x 10 days, the 2nd tetracycline 250 mg x 4 x 12 days, the 3rd group received no medication and served as a control. 6 patients had periodontal surgery. 4 sites with the most advanced bone loss as determined on radiographs were selected in each subject for test sites. Gingival index, gingival bleeding after probing (GB), probing depth (PD), suppuration, and radiographic bone loss were registered, and subgingival Aa was selectively cultured. GB and PD > or = 4 mm were registered in the whole dentition as well. All parameters were monitored at baseline and at 6 and 18 months after treatment. By the end of the study, Aa was suppressed to below detection level at all test sites only in the metronidazole group, at 17/26 sites (4 patients) in the tetracycline group and at 19/26 sites (6 patients) in the control group. Clinically, all groups showed improvement. In conclusion, metronidazole was more effective than tetracycline in the suppression of Aa and the suppression of Aa appeared to produce better clinical results.