• Bone replacement grafts enhance the effectiveness of enamel matrix derivative in the treatment of infrabony defects

      Behmanesh, Sara; Reynolds, Mark A., D.D.S., Ph.D. (2011)
      Background: Histologic studies in animals and humans have provided evidence that the treatment of periodontal defects with EMD promotes healing which is characterized by formation of a new attachment apparatus--namely, new bone, cementum and periodontal ligament. Nevertheless, improvements in clinical outcomes fail to completely restore the periodontium. Considerable interest has focused on the potential of combing EMD with bone replacement grafts to enhance the regeneration. Purpose: The purpose of this paper is systematic review of literature comparing use of EMD alone or in combination with bone replacement grafts in treatment of infrabony defects. Does the addition of a bone replacement graft to EMD improve clinical outcome compared to EMD alone in the treatment of infrabony defects? Methods: An electronic search of the databases MEDLINE and EMBASE was performed without any language limitations as well as hand searches of selected periodicals. Mean differences in clinical outcome measures (clinical attachment level, probing depth, recession, and defect fill) were submitted to a meta-analysis, including assessment for heterogeneity. The meta-analysis was computed using a random-effects model, with α-level set at p ≤ 0.05. Results: The search strategies identified 326 publications, with 10 studies fulfilling qualifications for inclusion in the analysis. A significant overall mean difference was found for defect fill, reflecting greater defect fill when EMD was combined with bone replacement graft compared to EMD treatment alone. No significant differences were found in improvements for mean clinical attachment level and reduction in probing depth. Conclusions: The potential for EMD to support hard tissue formation, as reflected in periodontal defect fill, can be enhanced by the addition of a bone replacement graft. Although a significant improvement in defect fill was shown for combination therapy, the overall mean improvement in defect fill was nonetheless modest in magnitude (≈ 1 mm). Moreover, no evidence was found for a corresponding difference in mean gain in clinical attachment level or probing depth. Thus, the potential benefit of greater defect fill on the therapeutic prognosis of the tooth must be considered in evaluating the cost-benefit ratio for combination therapy using EMD and bone replacement grafts.
    • The effect of neodymium:yttrium-aluminum-garnet laser treatment at different power settings and distances on hydroxyapatite-coated dental implants: A scanning electron microscope study

      Elbanhawy, Omar E.; Reynolds, Mark A., D.D.S., Ph.D. (2013)
      Aim: The purpose of this study was to evaluate the surface changes caused by a single pass of pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on hydroxyapatite (HA)-coated dental implant surfaces, and to report on the effect of varying the distance from the laser fiber tip to the implant surface on laser induced implant surface changes. Materials and methods: Nine HA-coated tapered screw vent implants (Zimmer Dental, Carlsbad, CA) were used in this study. The laser used was the Periolase<sup>TM</sup> MVP-7<sup>TM</sup>, which is a pulsed Nd:YAG (1062nm) laser. The effect of the laser was evaluated a distance of 3 mm and 10 mm away from implant surfaces at 3 different power settings (0.8 W, 2.0 W, and 3.0 W), which yielded 6 treatment groups: Group 1 (0.8 W at 3mm); Group 2 (0.8 W at 10mm): Group 3 (2.0 W at 3mm); Group 4 (2.0 W at 10mm); Group 5 (3.0 W at 3mm); and Group 6 (3.0 W at 10mm). The implants were examined for the area of surface damage using scanning electron microscopy (SEM). Measurements on SEM images were made at 350x magnification. Data were submitted to an analysis of variance with repeated measures. Results: The mean areas of surface damage were as follows: Group 1 891 μm2 ±129; Group 2 684μm2 ±227; Group 3 2825μm2 ±730; Group 4 2300μm2 ±590; Group 5 5225μm2 ±409; and Group 6 2397μm2 ±370. At 3 mm distance, the mean area of surface damage increased significantly with each higher level of energy. At 10mm distance, the mean area of surface damage increased significantly at 2.0 W and 3.0 W, when compared to 0.8 W; however, no difference was found between 2.0 W and 3.0 W. No obliteration of HA surface was noted. Conclusion: Within the limitations of this study, the surface effects of a single pass of Nd:YAG laser on HA-coated implants appear to be proportional to the laser power output and inversely proportional to the distance from the object being irradiated.
    • The Effectiveness of Regenerative Therapy in Achieving Complete Hard Tissue Closure of Mandibular Class II Furcations

      Lee, Eugenie Eunkyung; Reynolds, Mark A., D.D.S., Ph.D. (2011)
      Mandibular Class II furcation involvement poses a significant challenge for the treatment and prognosis of mandibular molars. Loss of bone due to advancing periodontal disease in the furcation area with its anatomic configuration leads to continual susceptibility to plaque-related inflammation, breakdown, and attachment loss since adequate debridement and maintenance is difficult. Numerous clinical studies demonstrate regenerative therapies can result in improved overall clinical furation measures with a wide range of clinical success, between 37-91%, for furcation closure. Clinical furcation closure is the most important outcome measurement to ensure proper maintenance by the patient and long-term success of therapy. The purpose of this study was to perform a systematic review of human clinical studies of mandibular Class II furcations treated with regenerative procedures to evaluate hard tissue closure of the furcation, horizontal defect fill (HDF). The search protocol was completed using the OVID database with predetermined inclusion and exclusion criteria, which produced 37 articles for analysis. To be included in this study, surgical re-entry outcome measures for mandibular class II furcations at least 6 months following regenerative therapy in humans had to be reported. Regenerative treatment showed a mean percentage horizontal defect furcation fill ranging from 34.3-46.4%, when adjusted for pre-treatment means. A subset of 17 studies reported the frequency of complete furcation closure yielding a range of 35.5-52.8% closure. Post-hoc comparisons for the effect on open horizontal defect depth revealed a significant difference between open flap debridement and regenerative theapy: bone replacement graft (BRG), guided tissue regeration (GTR) or combination therapy. Guided tissue regeneration (GTR) and combination therapy (GTR/BRG) were superior to open flap debridement in obtaining hard tissue fill. The BRG group produced imtermediate horizontal defect fill relative to open flap debridement and the GTR and GTR/BRG groups with no significant difference between BRG and the other two regenerative treatment groups. Regenerative therapies, according to summary statistics, yield improvements approaching 50% horizontal defect fill. Early diagnosis and treatment may most likely increase the probability of clinical closure. More studies are necessary evaluating the impact of biologic agents on the predictability of improved clinical outcome measures and furcation closure.
    • The effects of Neodymium: Yttrium-Aluminum-Garnet laser on the Osseotite® surface: An in vitro scanning electron microscope evaluation

      Rostami, Arash Mike; Reynolds, Mark A., D.D.S., Ph.D. (2013)
      Background: Recently Nd:YAG laser has been proposed as an option to decontaminate the implant surface. The aim of this study was to evaluate the effects of laser irradiation on Osseotite implant surfaces using the Nd:YAG laser. Methods: Four 3i Osseotite® implants were used with each implant providing 3 sides for observation. The implants were mounted in jig that moved the surface perpendicularly past a Nd:YAG laser beam. After positioning at 3mm or 10mm a fresh surface was irradiated with either 0.8w, 2w, or 3w delivered through a 360nm fiber optic tip. The specimens were evaluated using SEM microscopy and the surface area of alteration was recorded using Image J software. Results: The results demonstrated that implant surfaces irradiated with Nd:YAG, regardless of distance (3mm, or 10mm) or power setting (0.8-3W), showed alteration of the Osseotite® surface. Repeated ANOVA analysis showed surface alterations were significant with increased power settings, but not to distance (P=0.005). The altered areas on the implants included charring, bluing, loss of surface roughness and in severe cases, melting, blistering and loss of surface layer as viewed by SEM and clinical photos. Conclusion: Regardless of power setting or distance, use of Nd:YAG on the Osseotite® surfaces will produce surface alterations. The implications of these surface alterations on re-osseointegration are not known.
    • The Effects of Neodymium:Yttrium-Aluminum-Garnet Laser On the TiUnite® Surface at Set Distance and Energy Levels: An in vitro Scanning Electron Microscopic Evaluation

      Ward, Melody Daroogar; Reynolds, Mark A., D.D.S., Ph.D. (2013)
      Background: Lasers are increasingly being used in the treatment of ailing implants with peri-implantitis. This study sought to evaluate via scanning electron microscopy (SEM) the effect of a single pass of a Nd:YAG laser on the TiUnite® implant surface at pre-determined distance and energy levels. Methods: 6 irradiated NobelReplace® TiUnite® Tapered implants were mounted on a jig and pulled at a constant speed across a Nd:YAG laser at energy levels of 0.8W, 2.0W and 3.0W and at a distance of 3mm or 10mm. Each implant provided 3 treatment surfaces, one per energy setting at the set distance. The first three threads of each implant were selected for analysis under SEM. Imaging software was used to calculate the area of surface alteration for each thread. Results: It was found that the further the laser fiber optic was from the implants the greater the affected area. The area of effect at 3mm at the different energy levels was 21,490μm2 ±7,975, 48,986μm2 ±6,195 and 47,362μm2 ±5,810 for 0.8W, 2.0W and 3.0W, respectively. For the 10mm distance, the area of effect was 11,548μm2 ±3,287, 10,723μm2 ±5,651 and 14,403μm2 ±5,435. The altered areas on the implants included charring, blackening, loss of surface roughness and in severe cases melting, blistering and loss of surface layer. After repeated ANOVA, it was found that distance had a greater effect on implant surface alteration at higher energy levels (2.0W and 3.0W) than at the lower energy level of 0.8W indicating that distance becomes a more significant contributor to implant surface damage when higher energy levels are used. Conclusions: The application of Nd:YAG laser on all implants at all distances produced surface damage when observed under SEM with distance having a greater effect on implant surface changes at higher wattages. It remains to be investigated whether this surface damage is a hindrance to re-osseointegration after treatment of implants with laser.
    • Maxillary Sinus Morphology: A Radiographic Retrospective Evaluation of Sinus Septa in Caucasian and African-American Subjects

      Van-Dinh, Kim-Thi; Reynolds, Mark A., D.D.S., Ph.D.; Aichelmann-Reidy, Mary Beth (2012)
      Anatomic variations of maxillary sinus morphology including volume and septa impact the success of sinus augmentation procedures for dental implant placement. Anatomy has been investigated mainly with respect to age and gender; however, the effect of race has not been examined. The purpose of this study was to evaluate variations of maxillary septa sinus anatomy of African-American and Caucasian subjects, given differences significantly impact treatment success. This retrospective study examined consecutive computerized tomographic scans (CT) of patients scheduled for maxillary implant surgery at the University of Maryland School of Dentistry between 2009 to 2011. A total of 259 CT scans of 139 African-American and 120 Caucasian subjects were evaluated, of which, 62.5% of subjects (162/259) had identifiable septa. A total of 343 septa were identified in 518 sinuses (66.2%). Caucasians had more septa than African-Americans (1.56 compared to 1.09, p=0.006). The effect of gender was approaching significance (p=0.07). The adjusted mean number of sinus septa in female subjects was 1.48 compared to 1.17 in males. Sinuses were divided into three sections: anterior (premolars), middle (first and second molars), and posterior (third molar). In both the anterior and middle sections, race had a significant effect (p=0.033 and p=0.035). In the anterior, the adjusted mean number of septa for Caucasians was nearly twice that of African-Americans (0.32 compared to 0.17). In the middle section, the adjusted mean for African-Americans was 0.57 compared to 0.79. With respect to the posterior section, only gender had a significant effect (p=0.008). Women had an adjusted average of 0.51 septa compared to men with a 0.29 average. The majority of septa were found in the middle segment (51.3%, 176/343), and 17.5% (60/343) were identified in the anterior segment. Sinus septa complicate Schneiderian membrane elevation therefore increasing likelihood of membrane perforation, a common complication of sinus augmentation procedures. The dentally relevant sinus segments contain the majority of sinus septa (68.8%) and have a direct impact on clinicians performing sinus augmentation procedures. Both race and gender impact maxillary implant treatment planning with a greater frequency of detectable septa in Caucasians and females when compared to African-American males.
    • Maxillary Sinus Morphology: A Radiographic Retrospective Evaluation of the Posterior Superior Alveolar Artery in Caucasian and African-American Subjects

      Fontana, John Battista, III; Reynolds, Mark A., D.D.S., Ph.D. (2012)
      Maxillary sinus floor augmentation using a lateral window approach is commonly used to increase the alveolar bone available in the edentulous maxilla for dental implant placement. Although this grafting procedure is generally considered safe and predictable, intra-operative complications can involve anatomic variations related to sinus septa and vasculature. Morphologic variations in the maxillary sinus have been documented in Caucasians but not African Americans. The purpose of this retrospective study was to compare the anatomic location and diameter of the posterior superior (PSAA) alveolar artery in African-Americans and Caucasians. Computerized tomographic images of 219 patients (108 African American and 111 Caucasian) permitted radiographic assessment and morphometric comparison of the PSAA. The primary dependent measure was radiographic diameter of the PSAA. Secondary dependent measures included the vertical distance of the PSAA to both the crest of the alveolar ridge and the inferior-most aspect of the maxillary sinus. The association of race and gender to the dependent measures was assessed using an analysis of covariance, adjusting for body mass index. The prevalence of the artery differed significantly between African-Americans (72.2%) and Caucasians (43.2%). Mean artery diameter did not differ significantly between African-Americans and Caucasians (1.29 mm ± 0.05, 1.24 mm ± 0.06, respectively), when adjusted for BMI. Diameter of the PSAA exhibited a significant positive association with BMI (p ≤ 0.05). The mean distance from the PSAA to alveolar crest was significantly lower for Caucasian females than Caucasian males (13.30mm ± 1.15, 17.79mm ± 1.05, respectively), whereas no gender difference was found in African Americans. The more prevalent and potentially larger caliber PSAA in African-Americans and the more inferior position of the artery seen in Caucasians women must be taken into consideration when attempting maxillary sinus floor augmentation via a lateral approach.
    • Survival Rates of Narrow Diameter Implants

      Tuan, Lawrence C.; Reynolds, Mark A., D.D.S., Ph.D. (2011)
      Endosseous implants are used for the support of prostheses ranging from single tooth to complex full mouth rehabilitations. Longitudinal, retrospective and case series reports have shown the cumulative success for endosseous implants supporting various forms of prostheses to be highly successful. Frequently, bone grafting for sinus and ridge augmentation is performed to improve the osseous dimensions to accommodate the placement of dental implants in the ideal prosthetic position. Implants of smaller dimensions have become increasingly popular since implant site development, requiring bone grafting can be circumvented for the atrophied or reduced edentulous site. Reduced implant diameter and length result in proportional decreases in implant surface area. This confers a decreased implant-to-bone contact area. Biomechanically, implants of smaller dimensions have higher crestal strain, lower pull out force and lower structural integrity. Theoretically, this can translate to lower clinical success rate for implants of lesser dimensions. The purpose of this paper was to perform a systematic review of the available literature on the efficacy of narrow diameter implants by comparing implant survival rates. Electronic and manual search were conducted using Ovid and the bibliographies of relevant articles. Summary statistics and meta-analysis were performed using commercially available software. A total of 23 articles fulfilled the inclusion and exclusion criteria and were used for final data analysis. The result of this systematic review showed the survival rates and rate of marginal bone loss for narrow diameter implants to be comparable to regular diameter implants both in short and long term studies. Meta analysis of the data showed a significant difference in the survival rate between short (< 10mm) and regular length (≥ 10mm) narrow diameter implants, favoring regular length narrow diameter implants. Thus, it can be concluded that dental implants of smaller dimensions should be used with caution. Although clinical successes have been reported for both short or narrow diameter implants, the clinical effect of both dimensional factors, when combined is still not known. The use of shorter implants with diameter of less than 3.75mm cannot be substantiated.
    • Th17 Cells in Gingival Immunity and Their Key Role in Periodontitis Pathogenesis

      Dutzan, Nicolas; Reynolds, Mark A., D.D.S., Ph.D.; Moutsopoulos, Niki; 0000-0001-8343-0214 (2017)
      Periodontitis is a very common human disease characterized by inflammatory bone destruction in the oral cavity. It affects more than 64 million adults in the United States and is often linked to systemic or distant co-morbidities. T helper (Th) cells and specifically Th17 have been identified as important constituents of the inflammatory lesion in periodontitis. However, the specific role of Th17 cells in periodontitis and whether they drive inflammatory pathology is not fully understood. We performed a detailed characterization of gingival tissues and found that Th17 are amplified in the lesions of human periodontitis. In fact, Th17 cells represent the major source of IL-17A in humans and in animal models of periodontitis and we show that their accumulation in gingival tissues is IL-6 dependent. Th17 differentiation and IL-17A expression are tightly regulated by signal transducer and activator of transcription-3 (STAT3). To analyze the role of Th17/STAT3 in humans with periodontitis we have evaluated a large cohort of patients with autosomal dominant mutations in STAT3. Autosomal Dominant Hyper IgE Syndrome (AD-HIES) patients have a defect in Th17 differentiation and lack Th17 cells in the circulation. We clinically characterized patients with AD-HIES and evaluated Th17 responses in their oral tissues. We find that AD-HIES patients have reduced susceptibility to periodontitis and present minimal oral inflammation, consistent with blunted Th17 tissue responses. To mechanistically dissect the role of Th17 cells and STAT3 in periodontitis, we performed periodontitis induction in mouse models specifically lacking Th17 cells. Cd4creStat3floxed mice lacked Th17 cells but other sources of IL-17 producing cells were unaffected in gingival tissues and importantly, were resistant to inflammatory bone loss. These results demonstrate the key role of Th17 in periodontitis and suggest inhibition of Th17 through Stat3 in the treatment/prevention of disease. Indeed, we performed preclinical studies of Stat3 inhibition (using C188-9 inhibitor, a small-molecule compound designed to prevent Stat3 activation) and demonstrated that pharmacologic inhibition of Stat3 prevented inflammatory bone loss in periodontitis models. Our work uncovers the pathogenic potential of Th17 cells in periodontal inflammatory bone loss and suggests pharmacologic inhibition through STAT3 in the prevention of this common inflammatory disease.