A Randomized Clinical Trial Evaluating rh-FGF-2/ß-TCP in Periodontal Defects.

Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a ß-tricalcium phosphate (ß-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups-ß-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with ß-TCP-following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/ß-TCP groups with significant improvements over control and 0.1% rh-FGF-2/ß-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/ß-TCP (ClinicalTrials.gov NCT01728844).

"In-line" bipolar, steroid-eluting, high impedance, epimyocardial pacing lead.

Recent advances in electrode surface designs have eliminated traditional threshold differences between endo- and epicardial pacing leads. Since the epicardial approach offers the potential of direct left ventricular pacing and the transvenous approach may not be feasible or warranted in all instances, more advanced leads are being designed to optimize epicardial pacing capabilities. This study was conducted to evaluate a bipolar epimyocardial lead. Six immature canines (age 3 months) were instrumented. The lead (Medtronic model 10389) is a single-pass, "in-line" bipolar electrode with low current drain and high impedance, with an intramyocardial steroid-eluting cathode and nonsteroid epicardial anode. Twelve ventricular leads were implanted (two per animal) and the animals followed for 6 months with weekly analysis of pacing and sensing capabilities. Results at explant were compared with implant values and showed no significant differences between sensed R waves or in R wave slew rates in unipolar or bipolar modes. Explant lead impedances remained high in both modes: bipolar, 1658 +/- 331; and unipolar, 1327 +/- 308 omega (P < 0.05). Chronic voltage (V) threshold at 0.5 ms showed no significant change from implant values during the study: unipolar, 0.3 +/- 0.06 versus 1.0 +/- 0.8; and bipolar, 0.4 +/- 0.06 versus 1.6 +/- 1.2. Histologic review showed negligible fibrous reaction at the electrode-tissue interface. This study introduces a high impedance, low threshold, "in-line" bipolar pacing lead design capable of stable chronic pacing with implant facilitated by a single suture technique.

Successful regeneration of mandibular Class II furcation defects: an evidence-based treatment approach.

The purpose of the present evidence-based critical review was to define goals and outcomes for regenerative therapy of Class II furcation defects and rank the efficacy of current regenerative procedures based on the available literature. Meta-analysis was employed to quantitate the mean overall expected changes and compare various techniques. The evidence presented in the literature was used to determine factors affecting regeneration of Class II furcation defects. These factors were used to establish decision-making trees to enhance success and highlight potential shortcomings of the technique. Guided tissue regeneration, used alone or in combination with bone replacement grafts, had the highest overall ranking. Mean reduction in probing depths and gains in vertical and horizontal attachment levels were all statistically significant at 6 months. Similar results were obtained in the 12-month studies. Compared to flap debridement, guided tissue regeneration resulted in greater reduction in probing depths and greater gains in vertical and horizontal attachment levels. Guided tissue regeneration provided almost identical results whether used with or without root conditioning, suggesting that root conditioning does not offer an adjunctive effect. A combination of guided tissue regeneration and bone replacement grafts yielded better results than did guided tissue regeneration alone in reducing probing depths and increasing vertical attachment levels. The decision-making trees derived from analysis of these results may assist the clinician in improving success and predictability of guided tissue regeneration procedures in Class II furcation defects.

Improved epimyocardial pacing: initial experience with a new bipolar, steroid-eluting, high impedance lead design.

Epicardial pacing typically is associated with decreased pacing and sensing capabilities compared with the endocardial approach. Since endocardial pacing is neither appropriate nor possible in all instances, this study was conducted to evaluate a new concept in a chronic epimyocardial lead design in six 3-month-old growing dogs. The new bifurcated lead (Medtronic model 10401) is a low current drain, high impedance, steroid-eluting, bipolar design. The implant is facilitated by a suture attached with an atraumatic needle. Twelve ventricular leads were implanted (2 per animal) and followed for 6 months with weekly analysis of pacing and sensing capabilities. Results at explant were compared with implant values. There were no significant differences between implant and explant in sensed R waves, or in the slew rate of the R wave in unipolar or bipolar modes. Lead impedances at explant remained high in both modes: bipolar, 1550 +/- 223; unipolar, 1234 +/- 262 omega (P < 0.05). Chronic voltage (v) threshold at 0.5 msec showed no significant change from implant values during the study: unipolar, 0.4 +/- 0.2 vs 0.7 +/- 0.3; bipolar, 0.5 +/- 0.4 vs 1 +/- 0.5. Histologic evaluations of the electrode tissue interface demonstrated negligible fibrotic capsule formation. This study introduces a new, easily implanted, high impedance, low threshold, bipolar epimyocardial pacing lead design with excellent chronic pacing and sensing characteristics.

Clinical and radiographic healing pattern observations with combined regenerative techniques.

Clinical and radiographic healing observations were categorized into four patterns: rapid, typical, delayed, and adverse. While considerable overlap of characteristics was noted between the categories, singular factors or combinations of factors enabled pattern identification. The factor primarily associated with the rapid healing pattern was the appearance of bone in the former defect adjacent to the membrane at removal. In contrast, the adverse healing pattern depicted surface necrosis or loss of tissue height at membrane removal. One hundred random sites were evaluated, revealing 13% rapid healing patterns, 76% typical healing patterns, 8% delayed healing patterns, and 3% adverse healing patterns. With favorable patient compliance with oral hygiene and follow-up care, the rapid and typical healing patterns became clinically successful cases. The level of clinical success varied with the delayed healing pattern; the adverse pattern failed to achieve the therapeutic objective.

Long-term assessment of combined osseous composite grafting, root conditioning, and guided tissue regeneration.

Although the short-term success of guided tissue regeneration has been widely reported, few studies on the long-term success of treatment have been published. The present investigation assessed the 5-year results of guided tissue regeneration procedures used alone or in combination with root conditioning and osseous composite grafts. Results indicated that the long-term success of guided tissue regeneration was significantly enhanced by the addition of root conditioning and grafting procedures.

Subjective criteria and probing attachment loss to evaluate the effects of plaque control and root debridement.

11 adult patients with moderate to advanced periodontitis were treated with oral hygiene instruction and an initial, single episode of root debridement. Before therapy, 3 independent clinicians examined all patients and identified sites that in their opinion probably would not respond to the therapy and would continue to lose attachment. On 2 occasions, 3 and 12 months later, the clinicians re-examined and re-evaluated all patients and all sites. The results of therapy were also monitored by probing attachment level measurements performed every 3rd month. All 11 patients completed 24 months of follow-up, and 6 subjects were available until 36 months. Sites with probing attachment loss after 12, 24 and 36 months were identified using linear regression analysis and compared to the clinicians' prediction of probing attachment loss. The results demonstrated a limited agreement between probing attachment loss determined by linear regression and the clinicians' predictions of probing attachment loss. It appears that the traditional clinical signs and factors used to forecast and identify periodontal disease activity are only moderately associated with probing attachment loss. This suggests that attachment loss may be caused by several factors, at least following initial therapy. The progression of an inflammatory disease of microbial etiology may be only 1 of such causes. Further studies are needed to clarify the nature and cause of probing attachment loss.

Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

The growth in the dental literature continues to escalate, as evidenced by the publication of at least 326 new books in 1988 and 1989 and more than 20 new journals in 1989. There still appears to be undue emphasis on quantity instead of quality of research. This proliferation in the literature poses ever increasing difficulties to this Committee in filtering out the articles that are of particular interest to the members of the Academy and identifying those that are most likely to have a major impact on dental practice and service. The subjects covered include periodontics, caries and preventive dentistry, craniomandibular disorders, occlusion, pulp biology, ceramics, and restorative dental materials.

Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

Dental research continued to grow during 1988. Unfortunately the quality does not always parallel the quantity of publications. This report obviously does not encompass all of the literature but focuses on studies that are related to trends and to matters that are considered controversial. Likewise the particular interests of the members of the American Academy of Restorative Dentistry were taken into consideration. The subjects covered include periodontics, preventive dentistry, bulp biology, craniomandibular disorders, ceramics, color in restorative dentistry, and dental materials.

Method for antegrade/retrograde conduction discrimination using a standard atrial bipolar lead.

Significant differences between morphology, magnitude, and relative timing of antegrade and retrograde conduction were demonstrated on unipolar electrograms from a standard atrial bipolar J lead positioned in the right atrium in dogs. The morphology of the P wave sensed from the tip was more or less biphasic while the morphology of the P wave sensed from the ring was monophasic only and of lower frequency content. The unipolar-ring P wave was attenuated in retrograde as compared with the antegrade. During retrograde conduction the unipolar-ring signal returned to baseline earlier in time relative to the peak of the unipolar-tip signal, than it did during antegrade conduction. Based on these differences a sensing circuit capable of discriminating between antegrade and retrograde conduction was built. This discriminator circuit, which relies on a standard lead and simple electronics, functioned reliably in trials in dogs and thus may prove to be practical for use in future pacemakers.