Current evidence regarding periodontal disease as a risk factor in preterm birth

Preterm birth, resulting in babies born too little and too soon, is a major cause of morbidity. Evidence indicates that infections can be major risk factors in preterm birth. Case-control studies point to an association between periodontal infection and increased rates of preterm birth. This paper summarizes evidence to date and the strategies that ongoing intervention studies are using to answer the fundamental clinical question: can periodontal therapy reduce the risk of preterm birth?

Retrospective radiographic analysis of sinus graft and implant placement procedures from the Academy of Osseointegration Consensus Conference on Sinus Grafts

A retrospective quantitative radiographic analysis determined the effect of graft material and smoking status on the maintenance of graft height over 3 years. Analysis of variance models with planned comparison were constructed to compare mean graft change by (1) graft material and (2) smoking status. Maintenance of bone height was significantly greater in intraoral autogenous grafts versus allografts (P < .05). The effect of smoking on implant loss revealed a significant difference in implant survival (P < .05). Autogenous bone generally resulted in a more favorable outcome over a 3-year period. Smoking adversely impacted implant survival in sinus grafts.

Intrapocket anesthesia for scaling and root planing: results of a double-blind multicenter trial using lidocaine prilocaine dental gel

BACKGROUND

The efficacy of a novel anesthetic gel (lidocaine 25 mg/g plus prilocaine 25 mg/g in thermosetting agents) for non-invasive periodontal pocket anesthesia was evaluated.

METHODS

One hundred twenty-two (122) patients in 8 centers with moderate to severe periodontitis requiring scaling and root planing (SRP) were enrolled in this multicenter, randomized, double-blind, controlled clinical trial. The active dental gel or a matching placebo gel was applied into the periodontal pocket using a blunt applicator. Following a waiting period of 30 seconds to 2 minutes, scaling and root planing were performed. If the patient had any discomfort, a second application of the gel was applied. If the patient continued to experience discomfort, conventional anesthesia was offered. After all teeth in the test quadrant had received SRP, the overall pain was assessed by the patient using a 100 mm horizontal, ungraded visual analog scale in which the left side was marked "no pain" and the right side marked "worst pain imaginable." Patients also assessed pain by using a 5-point verbal rating scale, from "no pain" to "very severe pain."

RESULTS

The visual analog scale showed significant reductions in reported pain, favoring the active gel over the placebo (mean reduction, 8 mm; P <0.0005). The verbal rating scale revealed that 90% of patients treated with active gel reported no pain or mild pain compared to 64% of placebo-treated patients (P<0.001).

CONCLUSIONS

Intrapocket administration of lidocaine 25 mg/g plus prilocaine 25 mg/g and thermosetting agents may be effective for pain control for scaling and root planing and may offer an alternative to infiltration anesthesia.

Periodontal infection and preterm birth: results of a prospective study

BACKGROUND

Previous studies have suggested that chronic periodontal infection may be associated with preterm births. The authors conducted a prospective study to test for this association.

METHODS

A total of 1,313 pregnant women were recruited from the Perinatal Emphasis Research Center at the University of Alabama at Birmingham. Complete periodontal, medical and behavioral assessments were made between 21 and 24 weeks gestation. After delivery, medical records were consulted to determine each infant's gestational age at birth. From these data, the authors calculated relationships between periodontal disease and preterm birth, while adjusting for smoking, parity (the state or fact of having born offspring), race and maternal age. Results were expressed as odds ratios and 95 percent confidence intervals, or CIs.

RESULTS

Patients with severe or generalized periodontal disease had adjusted odds ratios (95 percent CI) of 4.45 (2.16-9.18) for preterm delivery (that is, before 37 weeks gestational age). The adjusted odds ratio increased with increasing prematurity to 5.28 (2.05-13.60) before 35 weeks' gestational age and to 7.07 (1.70-27.4) before 32 weeks' gestational age.

CONCLUSIONS

The authors' data show an association between the presence of periodontitis at 21 to 24 weeks' gestation and subsequent preterm birth. Further studies are needed to determine whether periodontitis is the cause.

CLINICAL IMPLICATIONS

While this large prospective study has shown a significant association between preterm birth and periodontitis at 21 to 24 weeks' gestation, neither it nor other studies to date were designed to determine whether treatment of periodontitis will reduce the risk of preterm birth. Pending an answer to this important question, it remains appropriate to advise expectant mothers about the importance of good oral health.

Implants in regenerated bone in a primate model

BACKGROUND

Earlier publications from our laboratory described the use of guided bone regeneration to fill large bone voids in the mandible created through en bloc resection in primates. The present report describes placement of implants into the regenerated bone with subsequent prostheses construction and loading.

METHODS

Lesions were created in the mandibles of 9 monkeys in a standardized mandibular defect of 8 x 19 mm. Reinforced expanded polytetrafluoroethylene membranes were placed in the animals and held in place with mini screws and sutures for anywhere from 1 to 12 months. No material was added to the defect. In each animal a root-form implant was placed 12 mm distal to the abutment teeth into the regenerated bone and was loaded with a prosthesis for 12 months. These implants were compared to original implants placed in the same monkeys years earlier in the same location in non-regenerated bone. Digital radiology and histomorphometry are described.

RESULTS

The results show that root-form implants placed in regenerated bone show the same radiological and histomorphometric characteristics as in normal bone when loaded. In addition, the percentage of bone contact with implants seen in regenerated bone versus non-regenerated bone is the same when both are loaded (65 +/- 13% SD in regenerated bone versus 59 +/- 15% SD in non-regenerated bone).

CONCLUSIONS

In a primate model root-form implants placed in regenerated bone and prosthetically loaded show no difference when compared to root-form implants placed in non-regenerated bone and prosthetically loaded.

Advances in measurements of periodontal bone and attachment loss

Periodontal probing and measurements using intraoral radiographs are widely utilized clinical techniques to measure attachment and bone levels, respectively. Determination of progressive disease, healing, or regeneration in clinical studies may require maximal sensitivity and attention to measurement error in order to assure that changes detected by new methodology are accurate. Both types of methods are susceptible to errors due to resolution, repeatability, and accuracy of the technique. While both probing and radiographic methods are useful in clinical trials they vary widely with respect to these errors. For example, manual probing is repeatable to within 1 mm better than 90% of the time, and state-of-the-art radiographic methods, such as digital subtraction radiography, can detect as little as 1 mg of bony change.

Persistent bacterial colonization of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans in periodontitis and its association with alveolar bone loss after 6 months of therapy

BACKGROUND, AIMS

The purpose of this study was to determine whether the presence of bacterial antigens for Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), and Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque of periodontitis patients after periodontal treatment was associated with progressive alveolar bone loss.

METHOD

39 (39) subjects in good general health previously diagnosed with adult periodontitis within the last 2 years, and still presenting with probing depth >5 mm in 2 to 6 teeth, were studied. All subjects were treated with scaling and root planing. Half of the subjects were randomly assigned to receive adjunctive systemic doxycycline (200 mg the 1st day, then 100 mg per day for 21 days). Subgingival plaque samples were taken at baseline, 1, 3 and 6 months after therapy. A modified ELISA test (Evalusite, Periodontal Test Kit, Eastman Kodak Co., Rochester, NY) was used to test for plaque antigens associated with P. gingivalis, P. intermedia and A. actinomycetemcomitans. Progressive alveolar bone loss was determined using digital subtraction radiography with standardized radiographs taken at baseline and 6 months after treatment.

RESULTS

The presence of P. gingivalis in plaque after treatment was significantly associated with progressive bone loss (positive predictive value 84%, negative predictive value 85%, odds ratio 31.9, p<0.0001). In contrast, the presence of P. intermedia in plaque after treatment was not indicative of progressive loss (positive predictive value 39%, negative predictive value 82%). Too few sites had evidence of A. actinomycetemcomitans to be amenable to statistical analysis. No significant difference in bone loss was attributable to the systemic antibiotic therapy.

CONCLUSION

These data indicated that, in this population, the presence of P. gingivalis in plaque after treatment might be indicative of progressive alveolar bone loss.

Periodontal disease progression

BACKGROUND

The objective of this investigation is to use noninvasive, state-of-the-art, diagnostic techniques to measure periodontal disease progression and model periodontal disease activity over time. In this investigation, digital subtraction radiography and an electronic controlled force periodontal probe capable of attachment level measurement were used to measure bone loss and attachment loss, respectively. The use of these nearly continuous measures of attachment and bone loss allowed detection of small amounts of disease activity and provided data to be used in modeling of the disease process over time.

METHODS

Forty-four patients were studied for 18 months. Examinations used clinical attachment level measures at 1-month intervals and quantitative radiology at 6-month intervals. The sites were analyzed by regression for statistically significant changes. These data were used to determine sites of periodontal disease activity for testing various models of periodontal disease progression.

RESULTS

Overall 22.8% of sites lost attachment, 5.4% gained, and 71.7% demonstrated no statistically significant change. The mean time to lose 1 mm of attachment was 8.4 +/- 0.6 months. In the first model tested a step-wise discriminant analysis was used to determine whether or not baseline measurements of plaque (PI), gingival inflammation (GI), attachment loss, and probing depth (PD) could be used to derive a satisfactory model for disease progression. Although the overall model was statistically significant with PI, PD, and GI contributing to the model (Wilks' lambda = 0.859, F = 5.71, P <0.0012), its predictive power was relatively weak. A considerably stronger significant model resulted when the rate of attachment loss over the first 6 months, baseline PI, and baseline GI were included (Wilks' lambda = 0.712, F = 14.17, P<0.00001). A significant model also resulted when bone loss during the first 6 months and baseline probing depth were included (Wilks' lambda = 0.438, F = 61.48, P<0.00001). When the last model was applied to each site, the sensitivity in predicting disease progression was 80.0% and the specificity in ruling out progressive disease was 93.9%.

CONCLUSIONS

This study indicates that clinically significant progression of attachment loss in posterior tooth sites occurs as a frequent event in adult periodontitis. The modeling data also suggest that short-term (6 month) measures of periodontal disease progression greatly improve the ability to model attachment loss over a longer period in untreated periodontitis patients.

Guided bone regeneration of large mandibular defects in a primate model

BACKGROUND

An earlier publication from our laboratory described the use of guided bone regeneration to fill large bone voids in the mandible created through en bloc resection in primates. The present report is an embellishment of this paper and describes bone regeneration experiments in 18 adult male Macaca mulatta monkeys to determine how long membranes must be in position to promote guided bone regeneration.

METHODS

Thirty-six lesions were created in the mandibles of 18 monkeys in a standardized mandibular defect of 8 x 19 mm. Reinforced ePTFE membranes were placed in the animals and held in place with mini screws and sutures for anywhere from 1 to 12 months. No material was added to the defect. In addition to clinical studies, digital subtraction radiology and fluorescent labeling with tetracycline and histomorphometry are described.

RESULTS

The results indicate that no bone gain was observed in membranes exposed for 1 month or less, but bone gain (approximately well over 90% of defects) was observed at 12 months when membranes were left in situ for 2 to 12 months (P <0.0001). No significant difference in the amount of bone gained at 12 months was observed for membranes left in place for intervals ranging from 2 to 12 months. A significant correlation between the amount of bone gain observed at 3 and 12 months was observed (P <0.0001).

CONCLUSIONS

Data therefore suggest that membranes left in situ for 1 month or less result in minimal bone gain compared with membranes left in place from 2 to 12 months. In addition, labeling and stained sections clearly showed that the bone produced after 2 months of membrane placement is mature.

Use of a biodegradable chlorhexidine chip in the treatment of adult periodontitis: clinical and radiographic findings

BACKGROUND

Previous multi-center trials demonstrated the efficacy of a biodegradable chlorhexidine-gelatin chip (CHX) in reducing probing depth in patients with periodontitis. The present study utilized a subset of subjects from the parent study to determine if the CHX chip was effective in maintaining alveolar bone over a 9-month period.

METHODS

Forty-five subjects with at least four 5 to 8 mm pockets, stratified by smoking status, were enrolled in this double-blind controlled, placebo-controlled trial. Control groups received either placebo chip plus scaling and root planing (SRP) or SRP alone. Test group subjects received active CHX chip or SRP alone (to maintain the blind). Standardized radiographs were taken for quantitative digital subtraction radiography at baseline and 9 months.

RESULTS

At 9 months, 15% of SRP treated subjects experienced loss of bone in 1 or more sites, no subject treated with active chip plus SRP lost bone (P <0.01). At 9 months, significant differences in the change in probing depth and clinical attachment levels favoring the active chip over SRP alone or SRP plus CHX chip were also observed (P <0.05).

CONCLUSIONS

These data indicate that the CHX chip, when used as an adjunct to scaling and root planing, significantly reduces loss of alveolar bone.

Preterm birth, osteoporosis, and periodontal disease

The purpose of this two-part article is to review two major events in the life span of a woman. These include the putative relationship between oral health, pregnancy, and postmenopausal osteoporosis. Current knowledge about risk factors for preterm birth and for osteoporosis are discussed. The newest studies that address the relationship between oral and systemic health are also reviewed.

Progression and treatment of chronic adult periodontitis

BACKGROUND

The periodontal status of 41 medically healthy adults with untreated chronic periodontitis was monitored before and after scaling and root planing (SRP).

METHODS

During a 6-month pretreatment phase, clinical measurements, digital subtraction radiography (DSR) analysis of alveolar bone, and measurement of gingival crevicular fluid (GCF) prostaglandin E2 (PGE2) levels were undertaken. SRP was provided during a 1-month treatment phase. Clinical, radiographic, and biochemical analyses were repeated in a 6-month post-treatment healing period.

RESULTS

Pretreatment: no clinically significant changes in mean plaque indices (PI), probing depths (PD), bleeding on probing (BOP), or relative clinical attachment levels (CAL) were detected (P>0.05). DSR revealed small but statistically significant bone height (0.04 mm) and mass (0.97 mg) loss (P<0.001). GCF PGE2 levels gradually increased from 38.8 ng/ml at month 1 to 79.4 ng/ml at month 6. Post-treatment: statistically and clinically significant reductions were observed in mean PI, BOP, and PD (P<0.05). A statistically significant reduction in CAL was noted (P<0.05). The trend towards progressive bone loss was halted and reversed, and a statistically significant decrease in GCF PGE2 concentrations was detected (P<0.001). Smokers, non-smokers, and ex-smokers did not differ significantly in PI, BOP, CAL, radiographic, or biochemical parameters at any time. Mean PD was significantly greater in current smokers than in non- and ex-smokers (P<0.005). PD reduced comparably in all 3 smoking subgroups following treatment (P<0.01).

CONCLUSIONS

Conventional clinical measurements failed to identify disease progression over a 6-month period. Significant improvements were observed in clinical parameters after SRP, and a trend towards progressive bone loss was halted and reversed. Regular and frequent maintenance visits are important following treatment to maintain improvements in clinical parameters. Smokers had deeper probing depths than non- and ex-smokers, but pockets were reduced significantly and comparably in all 3 smoking subgroups following efficacious treatment.

The cost-effectiveness of a new chlorhexidine delivery system in the treatment of adult periodontitis

BACKGROUND

Periodontal treatment is costly. The authors assessed the potential economic impact of a new periodontal chemotherapeutic, testing the hypothesis that its adjunctive use would result in reduced periodontal surgical needs.

METHODS

An economic model estimated treatment needs following two clinical trials of the adjunctive use of a chlorhexidine, or CHX, -containing chip compared with scaling and root planing, or SRP, alone. Needs were based on periodontal status at nine months and a probabilistic algorithm; costs were assigned on the basis of a national dental survey and an average wholesale price of the CHX chip.

RESULTS

The base case model projected significantly more maintenance procedures and significantly fewer periodontal surgical procedures for patients treated with SRP and the CHX chip compared with patients who were treated with SRP alone (54.4 percent vs. 46.4 percent, P = .014; 29.2 percent vs. 35.5 percent, P = .015, respectively). Average total costs of care for patients treated with SRP and CHX chip were $737 +/- $244 compared with $734 +/- $239 for patients treated with SRP alone. Sensitivity analyses to account for variations in practice patterns did not appreciably alter the results. When data were analyzed after only three or six months of treatment, the significant differences in treatment needs disappeared.

CONCLUSIONS

The CHX chip is a new, apparently cost-effective treatment option for non-surgical periodontal therapy. Adjunctive use of the CHX chip could reduce periodontal surgical needs significantly at little or no additional cost.

CLINICAL IMPLICATIONS

Results suggest that incorporating the CHX chip into routine practice requires a new algorithm for management of periodontal disease. To obtain full clinical benefit, treatment needs to be continued for nine months.

Longitudinal changes in TCRB variable gene expression and markers of gingival inflammation in experimental gingivitis

The aim of this study was to gain information of the cellular and molecular events which occur during the development of experimental gingivitis and to determine whether such changes occur in the presence or absence of alveolar bone resorption. Clinical, radiographic, biochemical and immunological variables were monitored in a 3-week, single-centre, experimental gingivitis study of 10 healthy volunteers. Following screening and professional prophylaxis to achieve visibly healthy gingival status, subjects abstained from all oral hygiene practises in one maxillary (test) quadrant for a period of 21 days. At days 0 and 21, in test and (contralateral) control quadrants, % bleeding on controlled pressure probing (% BOP) was calculated, and radiographic alveolar bone status was assessed using bilateral standardised vertical bite-wing radiographs and digital subtraction radiography (DSR) analysis. In test quadrants, gingival crevicular fluid (GCF) was sampled from 4 sites per subject with Periopaper strips, and prostaglandin E2 (PGE2) levels measured using an enzyme immunoassay (EIA) kit. At days 0, 7 and 21, one interdental papilla was surgically excised from the test quadrant, and the expression of T cell receptor B variable (TCRBV) genes was investigated using a reverse transcription-polymerase chain reaction (RT-PCR) procedure. At days 0, 7 and 21, peripheral blood lymphocytes (PBL) were isolated and additionally investigated for TCRBV gene expression. Following 21 days of plaque accumulation in test quadrants, a statistically significant increase in % BOP scores confirmed the presence of gingival inflammation (p<0.001). DSR analysis revealed that there were no significant alveolar bone changes in either the test or control quadrants between days 0 and 21 (p>0.05). EIA analysis of GCF samples identified a significant decrease in mean GCF PGE2 concentrations from day 0 to day 21 (p<0.05). RT-PCR analysis indicated that genes from all 3 TCRBV families studied (TCRBV-2, -6, -8) were expressed in the PBL samples at all time points and in healthy gingival tissues at day 0. A restriction in the expression pattern of TCRBV genes similar to those which have previously been reported in chronic periodontitis was noted at gingivitis sites. It is possible that such an event may identify susceptibility to periodontal disease independently of other positive predictive markers such as GCF-PGE2.

Adjunctive use of a subgingival controlled-release chlorhexidine chip reduces probing depth and improves attachment level compared with scaling and root planing alone

The present studies evaluated the efficacy of a controlled-release biodegradable chlorhexidine (CHX) (2.5 mg) chip when used as an adjunct to scaling and root planing on reducing probing depth (PD) and improving clinical attachment level (CAL) in adult periodontitis. Two double-blind, randomized, placebo-controlled multi-center clinical trials (5 centers each) were conducted; pooled data are reported from all 10 centers (447 patients). At baseline, following 1 hour of scaling and root planing (SRP) in patients free of supragingival calculus, the chip was placed in target sites with PD 5 to 8 mm which bled on probing. Chip placement was repeated at 3 and/or 6 months if PD remained > or = 5 mm. Study sites in active chip subjects received either CHX chip plus SRP or SRP alone (to maintain study blind). Sites in placebo chip subjects received either placebo chip plus SRP or SRP alone. Examinations were performed at baseline; 7 days; 6 weeks; and 3, 6, and 9 months. At 9 months significant reductions from baseline favoring the chlorhexidine chip compared with both control treatments were observed with respect to PD (chlorhexidine chip plus SRP, 0.95 +/- 0.05 mm; SRP alone, 0.65 +/- 0.05 mm, P < 0.001; placebo chip plus SRP, 0.69 +/- 0.05 mm, P < 0.001) and CAL (chlorhexidine chip plus SRP, 0.75 +/- 0.06 mm; SRP alone, 0.58 +/- 0.06 mm, P < 0.05; placebo chip plus SRP, 0.55 +/- 0.06 mm, P < 0.05). The proportion of patients who evidenced a PD reduction from baseline of 2 mm or more at 9 months was significantly greater in the chlorhexidine chip group (19%) compared with SRP controls (8%) (P < 0.05). Adverse effects were minor and transient toothache, including pain, tenderness, aching, throbbing, soreness, discomfort, or sensitivity was the only adverse effect that was higher in the chlorhexidine group as compared to placebo (P = 0.042). These data demonstrate that the adjunctive use of the chlorhexidine chip results in a significant reduction of PD when compared with both SRP alone or the adjunctive use of a placebo chip. These multi-center randomized control trials suggest that the chlorhexidine chip is a safe and effective adjunctive chemotherapy for the treatment of adult periodontitis.

Radiographic bone loss correlations and technetium-99m-MDP bone uptake in ligature-induced periodontal disease in the beagle

The goal of this study was to develop an animal model for the study of acute periodontal disease using silk ligatures in combination with a soft diet in eleven purebred beagle dogs. The silk ligatures were placed subgingivally on the mandible second and fourth premolar on one side of the mouth; the opposite side served as a control. Dogs were monitored during the 16-20 weeks of ligature placement, and for 48 weeks after ligature removal. Development of periodontal disease was evaluated by radiopharmaceutical uptake into bone, radiographic evidence of alveolar bone loss, attachment loss, gingival index and prostaglandin level. Bone loss occurred on the ligatured side during the ligature phase of the study. Radiopharmaceutical uptake was correlated with radiographic evidence of bone loss during the ligature phase. No significant bone loss occurred during the post-ligature phase. Progressive periodontal disease was induced during ligature placement. However, a chronic less aggressive form was not sustained by soft diet alone after ligature removal.

Osteoporosis: a possible modifying factor in oral bone loss

There has been increasing interest in the interrelationship between systemic osteoporosis, oral bone loss, tooth loss, and risk factors for these conditions. Because the severity of alveolar bone loss increases with age, it has long been hypothesized that it may, in part, be related to systemic conditions that also predispose the patient to osteoporosis/osteopenia. The purpose of this paper is to review the risk factors for osteoporosis and periodontitis, as well as the evidence that loss of oral bone mineral may be related to systemic osteopenia. There is also evidence that therapies designed to influence systemic bone mineral density, such as hormone replacement and bisphosphonate therapy, may be associated with less tooth loss and a slower loss of alveolar bone, respectively.

Semiautomated image registration for digital subtraction radiography

OBJECTIVE

The purpose of this study was to evaluate the semiautomatic alignment and correction of affine geometric discrepancies for digital subtraction radiography.

STUDY DESIGN

Algorithms were tested in vitro to determine their ability to semiautomatically select reference points on a second image based on points selected on a first (reference) image. A preserved human mandible was imaged with and without bone-equivalent material chips at varying degrees of angulation. Each chip had a mass of less than 10 mg and was no more than 0.3 mm thick. High levels of specificity and sensitivity for chip detection were achieved with 6 degrees of angular discrepancy or less. The algorithms were then applied to radiographs from six human subjects through use of the bone-chip validation model.

RESULTS

Sensitivity was 89% and 100% for the three-point and four-point affine warp algorithms, respectively. Specificity for both algorithms was 100%.

CONCLUSIONS

The data indicate that semiautomated alignment algorithms may enhance the efficacy of digital subtraction radiography while maintaining diagnostic efficacy in clinical trials.

Coordinate production of PGE2 and IL-1 beta in the gingival crevicular fluid of adults with periodontitis: its relationship to alveolar bone loss and disruption by twice daily treatment with ketorolac tromethamine oral rinse

The inflammatory mediators prostaglandin E2 (PGE2) and interleukin-1 beta (IL-1 beta) play critical roles in the inflammatory process leading to alveolar bone and connective tissue loss in periodontal disease. Data from a previously published 6-month clinical study demonstrated that twice daily use of 0.1% ketorolac tromethamine oral rinse prevented alveolar bone loss in adults with periodontitis. We further analyzed data from this study to examine the relationship between PGE2. IL-1 beta and bone loss. Patient mean PGE2 and IL-1 beta levels in gingival crevicular fluid (M-GCF) measured throughout the course of the study were directly compared to the maximum amount of alveolar bone height loss observed at a single study site in each patient. The maximum amount of bone loss measured was chosen for the analysis since the pattern of bone loss was clearly episodic in nature. A statistically significant correlation (r = 0.73, p = 0.001) exists between M-GCF PGE2 concentration and the maximum amount of bone height lost at individual patient study sites. The correlation between M-GCF IL-1 beta concentration and maximum bone height lost is also statistically significant (r = 0.66, p = 0.005). Over the 6-month duration of the study, both PGE2 and IL-1 beta were coordinately expressed in the placebo treatment group as reflected in the significant correlation between M-GCF concentrations of the 2 mediators (r = 0.81, p < 0.001). Treatment of patients with 0.1% ketorolac tromethamine twice daily for 6 months resulted in reductions of PGE2 in GCF and a negligible correlation between M-GCF PGE2 and M-GCF IL-1 beta (r = 0.42, p = 0.088). This lack of a strong association between the 2 mediators in the ketorolac treatment group provides a direct biochemical readout of the anti-inflammatory efficacy of ketorolac tromethamine oral rinse in patients with periodontitis. Further studies are warranted to determine the full diagnostic potential of M-GCF levels of PGE2 and IL-1 beta for predicting risk of alveolar bone loss in patients with periodontitis and monitoring periodontal therapy effectiveness.

Evidence-based periodontal treatment. Highlights from the 1996 World Workshop in Periodontics

State-of-the-art periodontal therapy involves a wide range of diagnostic and treatment options. The 1996 World Workshop in Periodontics used an evidence-based approach to assess the efficacy of many of these options. This article describes the evidence-based approach and summarizes the findings of the workshop in the areas of diagnosis and nonsurgical and surgical periodontal therapy as well as dental implants.

Blur reduction of conventional film-based tomograms for pre-surgical evaluation of potential mandibular implant sites

The usefulness of motion-based cross-sectional tomography to evaluate osseous support and adjacent anatomical structures for dental implant placement is limited by the inherent blurring in these images. The goal of this study was to develop a method to remove blurring while permitting accurate dimensional analysis of the potential implant site. Defined regions (anterior, cuspid, premolar, molar) on two preserved human mandibles were imaged using cross-sectional linear tomography. Algorithms were developed as a personal computer application to remove the blur and to aid in identification of the cortical plate borders and the mandibular canal. The data set of eight tomograms was digitized and the blur reduced with the developed algorithm. An operator measured the height and width of the mandible on each original tomogram and each deblurred tomogram in triplicate. Method error was calculated as the difference between direct caliper measurements of the respective skull regions and image measurements of height and width for both the original digitized tomograms and the deblurred tomograms. Method error using the original images (height: -2.72 +/- 2.15 mm; width: -0.58 +/- 1.36 mm) compared to the deblurred tomograms (height: -0.58 +/- 1.16 mm; width: 0.37 +/- 0.59 mm) was significantly greater for both height (t-test level of significance, P = 0.0047) and width (t-test level of significance, P = 0.0001). These findings suggest that the method developed may greatly improve the ability of clinicians to accurately assess the implant site using cross-sectional film-based linear tomograms.

The effect of ketoprofen creams on periodontal disease in rhesus monkeys

Ketoprofen creams were evaluated for the treatment of periodontal disease in a placebo-controlled, double-blind study in the rhesus monkeys, Macaca mulatta. Two formulations containing ketoprofen (1%), with or without vitamin E, were evaluated against appropriate controls (8 monkeys per group). Two weeks prior to treatment, the animals received prophylaxis on only the left side of the mouth (spontaneous model). Selected teeth on the right side of the mouth were ligated (ligature model). The creams were administered to the gingiva once daily at a standard dose of 1.8 ml per monkey for 6 months. Clinical assessments were made 2 wk before initiation, at baseline and 1, 2, 3 and 6 months post-treatment. The clinical parameters included plaque formation, gingival redness, edema, bleeding on probing and Ramfjord Attachment Level measurements (RAL). Radiographs were taken at 2 wk before initiation, baseline and at 3 and 6 months post-treatment. Digital, subtraction radiography was used to measure vertical linear bone loss along the interproximal root surfaces of the left and right mandibular first molars. Gingival crevicular fluid (GCF) was collected for biochemical assays on PGE2, TxB2, LTB4, IL-1 beta and TNF alpha. There were no significant differences among groups with respect to gingival indices. Radiographic data demonstrated significant positive effects on bone activity in both groups treated with ketoprofen formulations with improvement over time in the ligature model (0.01 < or = p < or = 0.04). The placebo group exhibited bone loss of 1.96 +/- 0.48 and 1.40 +/- 0.56 mm per site at 3 and 6 months, respectively. The group treated with ketoprofen cream showed an apparent bone gain of 0.28 +/- 0.41 and 0.78 +/- 0.47 mm per site at 3 and 6 months, respectively. The group treated with ketoprofen cream containing vitamin E showed a mean bone loss of 0.41-0.48 mm per site at 3 months with improvement to an apparent bone gain of 0.31 +/- 0.44 mm per site at 6 months. The biochemical data demonstrated early and significant suppression of GCF-LTB4 by both ketoprofen formulations at 1 month, which preceded the significant suppression of GCF-PGE2 at 2 and 3 months in the ligature model (p < 0.003) and at 2 to 6 months in the spontaneous model (p < 0.02). We conclude that ketoprofen at 1% level in suitable topical vehicles can effectively inhibit GCF-LTB4 and GCF-PGE2 and positively alter alveolar bone activity in the ligature-induced model of periodontitis in the monkey.

Clinical and radiographic digital imaging evaluation of a bioresorbable membrane in the treatment of periodontal bone defects

This study evaluated the use of a bioresorbable membrane (Guidor USA) for treatment of periodontal angular bone defects in eight periodontitis patients. Presurgical measurements consisted of probing depth, clinical attachment levels, and digital radiographic imaging evaluation. Full-thickness buccal and lingual flaps were elevated allowing for soft tissue debridement, scaling, and root planing. Bioresorbable membranes were placed in at least one of the periodontal defects, and controls were left without barrier placement. Clinical and radiographic results 6 months after the surgical procedure showed clinical and radiographic improvement for control and test lesions. However, sites treated with bioresorbable membranes presented a significant gain in clinical attachment and bone mass when compared to sites that had received flap surgery alone.

Comparison between 2 surgical techniques for the treatment of early-onset periodontitis

The objective of this study was to compare guided tissue regeneration (GTR) and osseous surgery (OS) in treatment of early-onset periodontitis. Six patients participated in this research, presenting 15 paired defects randomly assigned to 1 of the surgical groups. Pre-operative clinical parameters (probing depth and attachment loss) between the two groups were not significantly different. Results 1 year following surgery showed probing depth reduction (2.60 +/- 1.30 mm) and clinical attachment gain (2.20 +/- 1.42 mm) were significantly greater in the GTR group than in the osseous surgery group (P < 0.05). The gingival recession was -0.53 +/- 0.52 mm and -0.40 +/- 0.74 mm for the osseous and the guided tissue regeneration group, respectively (no significant difference, P > 0.05). Radiographic analysis by two techniques illustrated that the interproximal alveolar bone changes at the margin of the defects in the OS group were slightly decreased (-0.20 +/- 1.15; 0.26 +/- 0.74 mm) and those in the GTR group were slightly increased (0.16 +/- 0.96; 0.26 +/- 0.68 mm), but showed no significant difference (P > 0.05). The base of the GTR-treated defects showed significant increase in bone fill (1.67 +/- 0.68; 1.97 +/- 0.74 mm; P < 0.05). At a follow-up reexamination 1 year following surgery, oral hygiene and gingival conditions in both groups were at satisfactory levels and gingiva was clinically healthy throughout the entire study period, except the first 4 to 6 weeks following surgery.

Efficacy of quantitative digital subtraction radiography using radiographs exposed in a multicenter trial

Digital subtraction radiography (DSR) has been shown to be a sensitive and specific method for the detection of small bony changes in periodontitis. The purpose of this study was to perform a multicenter validation of the DSR in human subjects. Seventeen subjects were enrolled at 3 centers. Feather-edged hydroxyapatite chips (approximately 1, 7 and 10 mg) were used to simulate osseous lesions. Bilateral radiographs were taken with and without chips. Geometry was standardized using a cephalostat and the order of radiographs was determined using a randomization plan. Radiographs were subtracted, lesions isolated, and quantified at a single center without knowledge of the randomization code or location of the chips used in each subject. The overall sensitivity and specificity in detecting 1 mg changes was 87.8% and 100%, respectively. Sensitivity and specificity in detecting 7 mg and 10 mg chips was 100%. A strong linear relationship between actual lesion mass and calculated mass was observed (R2 = 0.94, slope = 0.98, p < 0.0001). No significant differences were observed by center. These data indicate that the DSR is a valid technique for the assessment of alveolar bone changes in multicenter trials.

Risk factors in dental implant failure

The goal of this study was to assess risk factors for dental implant failure. Eighty-three implants were placed in thirty patients who were followed for three years using digital subtraction radiography. The following putative risk factors for implant failure were employed in the model: age, sex, implant length, implant position, implant surface coating, smoking habit, and presence of infection. Implant failure was defined as progressive bone loss compromising the implant. We found that the presence of infection (P < 0.001) and absence of HA coating (P < 0.001) were the primary factors associated with early implant failure.

A comparison of topical ketorolac, systemic flurbiprofen, and placebo for the inhibition of bone loss in adult periodontitis

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.

Alendronate treatment of naturally-occurring periodontitis in beagle dogs

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 effect of systemic flurbiprofen on bone supporting dental implants

This article describes a study of the efficacy of the non-steroidal anti-inflammatory drug flurbiprofen in maintaining alveolar bone around mandibular root-form dental implants. The preliminary results indicate that, in appropriate doses, flurbiprofen may spare bone around such implants.

Dental education at the crossroads: a report by the Institute of Medicine

Today's dental schools confront an environment in higher education and health care that promises less stable financing and, thus, more uncertainty for faculty, students, researchers and administrators. A new report from the Institute of Medicine underscores the need for changes in dental education to prepare for a future that will in many important ways be quite different from the past.

Research, technology transfer, and dentistry

The periodontal discipline illustrates the need for dentists to be doctors specializing in oral medicine. Research findings are tending toward more complex and possibly lengthy treatment with drugs and/or growth factors, necessitating a curriculum with more emphasis on pharmacology, medical management, critical review of clinical trial results, and evaluation of risk-benefit ratios.

A comparison of the diagnostic advantages of panoramic radiography and computed tomography scanning for placement of root form dental implants

This study evaluated the advantages of computed tomography (CT) in comparison to routine panoramic radiography for dental implant treatment planning. An in vitro validation study was performed to assess the accuracy of CT and panoramic radiography film images for measurement of anatomic structures and distances between anatomic structures. After correcting by a standard 25% magnification on the panoramic images, a significant difference in measurements was found between the CT and panoramic radiography images. Ten subjects requiring implants in compromised ridges were treatment planned with either CT and panoramic radiographs or panoramic radiographs alone. The ideal implant length was determined at surgery with direct digital radiography. The dentists were significantly more confident using CT and panoramic images than panoramic radiographs alone. Implant length treatment planned with panoramic radiography alone underestimated length significantly compared with the implant length determined to be ideal during surgery, whereas treatment planning with CT and panoramic radiography demonstrated no significant difference. The data indicate the CT may be of value in treatment planning for dental implants, especially when gaining maximum length is of critical importance.

An adaptable head retention and alignment device for computed tomography scanning of Macaca mulatta

An adaptable retention device has been developed for the purpose of holding and aligning the head of a sedated primate subject during computed tomography (CT) scan procedures. The device is used to obtain a close reproduction of CT scan studies at a time before and after dental implant placement in the mandibles of nine subjects. Geometric and material properties are extracted from these studies for the purpose of developing finite elements computer models. The device is constructed of low-density acrylic and consists of a horizontal base to which lateral supports are affixed. The device is placed on the CT table and axially aligned with the scan beam. Repeatable, calibrated CT studies of primate implant subjects were possible using the head holding device.

Prevention of periodontal diseases in adults: strategies for the future

Gingivitis and periodontitis are the most prevalent periodontal diseases in adults. Gingivitis is characterized by inflammation of the gingiva without loss of connective tissue attachment to the teeth while periodontitis results in loss of attachment and alveolar bone and may lead to tooth loss. Gingivitis is highly prevalent in adults in the United States, and up to 70% of adults have at least mild periodontitis. In only a small proportion of adults (< 15%) does periodontitis progress to severe disease. The etiology of periodontal disease is infection with pathogenic dental plaque bacteria in a susceptible host. Strategies for preventing periodontal diseases therefore may intervene at the level of the initiation of the inflammatory process, or by preventing the progression of bone and attachment loss in periodontitis. Improved mechanical and chemical plaque control as well as improved restorative materials to facilitate plaque removal continue to enhance the patient's ability to control the plaque bacteria. Strategies to target prevention to the patients who need it most include risk factor assessment, new diagnostic methods, and further elucidation of the natural history of periodontal disease. Further study of the etiology and pathophysiology of periodontitis will aid in the prevention of further destruction through targeted use of local and systemic antibiotics and well as drugs to aid in the host response. Ultimately research may yield multivalent vaccines to be used in high-risk patients.

Current concepts in periodontal disease testing

Tests for periodontal disease fall into four categories. The test may identify putative periodontopathic plaque bacteria, the susceptible host, metabolic changes associated with inflammation, tissue damage or death or anatomic changes including periodontal probing and radiographs. The current understanding of tests for periodontal disease is reviewed within a framework for understanding the rationale for such tests.

Longitudinal evaluation of elastase as a marker for the progression of periodontitis

To determine whether elastase levels in gingival crevicular fluid (GCF) could serve as a marker for the progression of periodontitis, we monitored GCF elastase and periodontal status in selected sites in 32 periodontally healthy volunteers and 31 periodontitis patients at intervals over a 6-month period. Clinical measurements included plaque index, gingival index, bleeding on probing, suppuration, probing depth, clinical attachment level, and relative attachment level measured with an automated disk probe. GCF elastase, detected by reaction with a fluorescent substrate, was assessed visually against fluorescence standards and quantitatively with a fluorometer. Bone loss was detected by subtraction radiography of standardized vertical bite-wing radiographs at baseline and 6 months. Mean visual elastase scores (VES) and quantitative elastase measurements were significantly higher (P < 0.001) in sites from periodontitis patients than in sites from healthy volunteers. When bone loss was used as the criterion for disease progression, significantly higher (P < 0.001) visual and quantitative GCF elastase levels were found at progressing sites than in nonprogressing sites in the periodontitis patients. The odds ratios (OR) for the event of developing bone loss with positive 4-minute and 8-minute VES tests were 4.2 (P < 0.001) and 7.4 (P < 0.001), respectively. When corrected for the tendency of progressing sites to be clustered within a subpopulation of patients, the OR for developing bone loss with the 4-minute and 8-minute VES tests were 3.1 (P < 0.007) and 4.9 (P < 0.001), respectively. These data indicate that sites with high levels of elastase are at significantly greater risk for progressive bone loss as assessed by digital subtraction radiography.

Bone loss in the oral cavity

Bone loss in the oral cavity may occur due to many causes, including infection, systemic or local alterations in the host response, or multifactorial causes. The purpose of this article is to review our present understanding of the major causes of oral bone loss in adults, with special emphasis on two major oral diseases: periodontitis and residual ridge resorption. Periodontitis is characterized by resorption of the alveolar bone as well as loss of the soft tissue attachment to the tooth. Progressive periodontitis will result in continued alveolar bone loss and may result in tooth mobility, abscesses, and ultimately tooth loss. Although the reported prevalence may vary according to the epidemiologic study design, the 1985 National Survey of Oral Health of United States Adults indicated that 94% of female senior citizens examined demonstrated at least one site with at least 2 mm loss of attachment. Resorption of alveolar bone that occurs following tooth extraction is termed residual ridge resorption. In many cases, the denture will loosen because of the inability of the resorbed ridge to stabilize the prosthesis. In the most severe cases, the denture may impinge on the exposed mandibular nerve, resulting in pain or total inability to tolerate the prostheses. Although clear statistics on the prevalence of residual ridge resorption are not available, this boss loss may result in the need for new dentures to replace ill-fitting prostheses.

Effects of nonsteroidal antiinflammatory drugs on bone loss in chronic inflammatory disease

Several controlled clinical trials have indicated that nonsteroidal antiinflammatory drugs may slow alveolar bone loss in periodontitis. Demonstration of this efficacy is dependent on the development of accurate, sensitive, and specific quantitative methods for the assessment of bony change, such as digital subtraction radiography. Further studies of such methodologies are required to more fully investigate the effect of nonsteroidal antiinflammatory drugs in rheumatoid arthritis.

Systemic osteoporosis and oral bone loss: evidence shows increased risk factors

Aging is associated with a loss of bone mass and an increased risk of oral and systemic bone loss. Systemic osteoporosis can result in bone fractures, especially of the spine and hip, with the characteristic spinal curvature and loss of height often seen in osteoporotic postmenopausal women. Loss of teeth and ridge resorption can occur in the mouth.

Efficacy of meclofenamate sodium (Meclomen) in the treatment of rapidly progressive periodontitis

This 6-month, double-blind, controlled clinical trial determined the efficacy of the non-steroidal anti-inflammatory drug, meclofenamate sodium (Meclomen), as an adjunct to scaling and root planing in the treatment of rapidly progressive periodontitis (RPP). 22 subjects (7 male, 15 female) aged 36.5 +/- 7.88 years with RPP and disease-active sites as determined by pretreatment bone scan had standardized radiographs at baseline and 6 months, and clinical measurements at baseline, 3 and 6 months. Following full-mouth scaling and root planing, subjects were randomly assigned to either a placebo, 50 or 100 mg meclofenamate sodium bid group. Bone change over the 6-month period as assessed by subtraction radiography was the primary efficacy determinant. Specialized software was used to isolate the lesion from the subtraction image and to measure bone change along the root surface. ANOVA using the subject as the unit of analysis revealed a significant dose response (p < 0.001) with the placebo group having a mean bone loss of 0.42 +/- 0.06 mm and the low and high dose groups having mean bone gains of 0.07 +/- 0.05 and 0.20 +/- 0.07 mm, respectively. These findings indicate that meclofenamate sodium may be a useful adjunct in the treatment of rapidly progressive periodontitis.

Digital subtraction radiography

Subtraction radiography offers greater visualization of radiographic changes between a pair of radiographs by subtracting out the unchanging background distractions. Originally, subtraction was achieved by using positive and negative prints in angiography. The advent of digital imaging devices has led to validation of quantitative measurements from digital subtraction images. As well, computer software manipulations have allowed for more flexibility in the clinical application of subtraction imaging. The clinical application of digital subtraction radiography is discussed along with clinical cases.

Application of digital radiography to implantology

Modern digital radiographic techniques can aid the clinician in planning dental implant selection and placement before and during surgery, a well as in the long term assessment of periimplant bone support. Implant treatment planning can be facilitated using computed tomography on film-based motion tomography. During surgery, direct digital radiography allows the clinician to visualize the relationship of the osteotomy sit to important anatomic structures such as the mandibular nerve. Following placement, digital subtraction radiography permits detection of osseous changes too small to be seen by eye with an accuracy approaching 95%. Such sensitivity and specificity encourages early evaluation and, if necessary, intervention on behalf of the ailing implant.

Digital subtraction radiography for longitudinal assessment of peri-implant bone change: method and validation

The purpose of this paper is to present a digital subtraction technique for the assessment of peri-implant bone change over time in vivo. Digital subtraction radiography may be used to detect areas of bony change that have occurred between radiographic examinations, and image processing algorithms have been developed which can relate the magnitude of the change on the subtraction image to a reference wedge, thereby allowing calculation of the mass of the lesion. This manuscript will present two algorithms for the assessment of osseous change. The method was validated in monkeys by means of small bony chips placed intra-orally prior to the first radiograph. The chips were removed, a second radiograph taken, and the images subtracted. Each algorithm was used to isolate the lesion and calculate change in bone mass. Overall, there was excellent correlation between the calculated lesion mass (in milligrams) and actual lesion mass (r2 > 0.9). The utility of the method was demonstrated by comparison of the results of subtraction radiography in successful implants and in implants that did not integrate during the healing phase.