Analyzing the accuracy of a cross-mounting technique utilizing digitized interocclusal records.

PURPOSE: To compare the accuracy of a partially digital cross-mounting workflow of direct scans of interocclusal records to a conventional workflow by analyzing the deviations of sequentially cross-mounted casts. MATERIALS AND METHODS: A set of reference casts, comprising maxillary and mandibular full-arch prepared casts and interim prostheses, was articulated, mounted, and scanned to generate four reference casts for cross-mounting. In the conventional approach, 15 sets of these four casts were printed. Polyvinylsiloxane (PVS) records were made using the reference casts and utilized for sequential cross-mounting. In the partially digital group, the same PVS interocclusal records were scanned and used for digital cross-mounting via design software. The mean deviations of both groups from the reference cast were analyzed using a 3D inspection software program. Statistical tests, including paired t-test and analysis of variance (ANOVA), were conducted to compare the average discrepancies between the two groups and to evaluate discrepancies in the anterior and posterior regions (α = 0.05). RESULTS: The range of discrepancies was similar in both the conventional and partially digital groups. The final set of related casts had a mean deviation of 201.58 ± 136.98 mm in the conventional workflow and 248.69 ± 164.71 mm in the partially digital workflow. No statistically significant difference was found between conventional and partially digital groups (p = 0.091). Error propagation was examined by comparing discrepancies at each step within the cross-mounting process. In the conventional group, no significant difference was found (p = 0.148), but a significant difference was found among groups in the partially digital group at each step of sequential mounting (p < 0.001). A significant difference was observed between anterior and posterior deviations in the partially digital group (p < 0.001), but not in the conventional group (p = 0.143). CONCLUSIONS: The study reveals that there is no statistically significant difference between conventional and partially digital cross-mounting workflows. However, within the partially digital group, a significant difference in deviation emerges across cross-mounting steps, with increased deviation in the anterior region.

Comparison of accuracy in digital and conventional cross-mounting.

STATEMENT OF PROBLEM: The use of digital interocclusal registration scans for virtual articulation and mounting has been studied extensively; however, the accuracy of the cross-mounting procedures in a digital workflow is not well understood. PURPOSE: The purpose of this in vitro study was to compare the accuracy of digital and conventional cross-mounting by measuring the 3-dimensional deviation at each step of sequential cross-mounting. MATERIAL AND METHODS: A set of reference casts and complete-arch interim restorations was prepared for complete-arch complete-coverage restorations, hand-articulated, and mounted in an articulator. The reference casts were then scanned with and without the interim restorations to generate 4 reference casts for cross-mounting. For the conventional group, 15 sets of the 4 casts were printed. Polyvinyl siloxane interocclusal registration records were made of the reference casts for each set, and casts were sequentially cross-mounted. For the digital workflow, 15 sets of bilateral interocclusal registration scans were made of the mounted reference casts and used to align the cast scans. Three-dimensional deviations at 2 anterior and 2 posterior points were recorded between the experimental mountings and the reference casts on each set of casts. Nonpaired t test and analysis of variance (ANOVA) were used to compare the average discrepancy between the 2 groups, and the pooled anterior versus posterior discrepancies were compared (α=.05). RESULTS: A significant difference was found between conventional and digital cross-mounting procedures (P<.001), but no significant difference was found in either group, conventional (P=.116) or digital (P=.987), at each step of the sequential mountings. The mean ±standard deviation at the final set of related casts in the conventional workflow was 201.6 ±137.0 µm and that in the digital group was 50.3 ±47.5 µm, with a significant difference between anterior and posterior deviations in the digital group (P=.028), but not in the conventional group (P=.143). The mean ±standard deviation anterior conventional deviation was 175.6 ±119.2 µm and that in the digital group was 36.9 ±30.9 µm. The mean ±standard deviation posterior conventional deviation was 227.6 ±50.2 µm and that in the digital group was 63.7 ±57.2 µm. CONCLUSIONS: Digital cross-mounting was more accurate than conventional cross-mounting, although increased deviation was found in the anterior region compared with the posterior region.

Regenerative Treatment of Advanced Peri-implantitis: A Retrospective Case Series with 3 to 15 Years of Follow-up.

The present case series evaluated implant survival and changes in bleeding on probing (BOP), probing depths, marginal tissue levels (recession), and bone levels following regenerative treatment of implants with advanced peri-implantitis. Forty-six implants with advanced peri-implantitis in 38 patients were treated with a regenerative protocol and evaluated for the above parameters at the final follow-up 3 to 15 years later. Patients returned every 2 to 3 months for maintenance and at the final evaluation. Measurements were made and compared to those recorded preoperatively. No implant was lost, BOP was reduced to 0 on all but 4 implants, the mean reduction in pocket depth was 6.7 mm, and the average soft tissue marginal position was 0.9 mm coronal to presurgical levels. Bone level changes showed a mean gain of 3.6 mm (radiographically) and 6.8 mm (bone sounding). These results appear to indicate that an implant with > 50% bone loss caused by peri-implantitis can successfully be treated and retained using a specific regenerative technique.

A Retrospective Study of Bone-Level Stability Around 335 Hybrid Implants Placed with an Immediate or Delayed Protocol.

This retrospective study evaluated 335 hybrid implants placed in edentulous ridges; 167 were placed with an immediate implant protocol (IIP) and 168 were placed with a delayed implant protocol. Radiographic bone level changes were measured 1 to 23 years after loading. The average bone loss between implant placement and second-stage loading was 0.16 mm in the delayed group and 0.12 mm in the IIP group. Average bone loss from implant loading to the final radiograph was 0.26 mm in the IIP group and 0.13 mm in the delayed group. There was statistically significantly more bone loss in the IIP group, in patients taking amoxicillin (vs those taking azithromycin), in sites with splinted implants (vs nonsplinted implants), and in smokers (vs nonsmokers). However, even when statistically significant, bone loss would be considered clinically insignificant by most clinicians over the 1- to 23-year follow-up.

Comparison of Intraoral and Extraoral Digital Scanners: Evaluation of Surface Topography and Precision.

The aim of this study was to evaluate the surface topography and the precision measurements of different intraoral and extraoral digital scanners. A reference model of a maxillary arch with four implant analogs was prepared and scanned by three intraoral and two extraoral scanners. The reference model was scanned fifteen times with each digital scanning system, investigating the surface topography and precision measurements for the same-arch and cross-arch measurements. The data was exported to 3D inspection and mesh-processing software (GOM Inspect, Braunschweig, Germany). Statistical analysis was performed using a one-way Analysis of Variance (ANOVA) with the Tukey method for pairwise comparisons. The effect of parameters on generating the surface topography was analyzed by Univariate Linear Regression Analysis. Of the scanner systems evaluated, iTero (IT) exhibited the most number of triangulation points, followed by Trios 3 Shape (TR) and Straumann Cares (SC). There were no significant differences observed in the surface topography when comparing flat and contoured surfaces, the anterior and posterior position, and interproximal areas. For the precision measurement in the same quadrant, no statistical difference was noted between intra- and extraoral scanners. However, the extraoral scanners showed substantially higher precision measurements for the cross-arch measurement. Surface topography did not correlate to precision. Rather, precision correlated with the scanning mechanism. For a quadrant scanning, both intraoral and extraoral scanners are recommended, but extraoral scanners are recommended for a full-arch scanning.

Physical impacts of PLGA scaffolding on hMSCs: Recovery neurobiology insight for implant design to treat spinal cord injury.

Our earlier work generated a powerful platform technology of polymeric scaffolding of stem cells to investigate and treat the injured or diseased central nervous system. However, the reciprocal sequelae between biophysical properties of the polymer and responses of the stem cell have not been examined in situ in lesioned spinal cords. We postulated that implantable synthetic scaffolds, acting through physical features, might affect donor cell behavior and host tissue remodeling. To test this hypothesis, poly(d,l-lactic-co-glycolic acid) (PLGA) in either low/soft or high/hard rigidity was fabricated for carrying adult human bone marrow mesenchymal stromal stem cells (hMSCs). The construct was transplanted into the epicenter of a rat model of acute T9-10 segmental hemisection to evaluate the effect of PLGA rigidity on the therapeutic potential and fate of hMSCs for neural repair. Compared to controls, only treatment with soft PLGA-scaffolded hMSCs significantly improved sensorimotor function via activation of recovery neurobiology mechanisms. The main benefits included inhibiting neuroinflammation and enhancing tissue protection. Also detected in the treated lesion region were expressions of neurotrophic and anti-inflammatory factors together with proliferation of endogenous neural stem cells, impacts likely derived from hMSCs' functional multipotency maintained by soft PLGA-scaffolding. Conversely, hard rigidity PLGA activated mechanotransduction and mesoderm lineage differentiation of hMSCs that ectopically produced bone, cartilage and muscle markers in neural parenchyma. The findings collectively suggested that the physical texture of polymeric scaffolds should be tailored for sustaining the stemness of hMSCs to constructively interact with the spinal cord for functional restoration.

Prospective 1-Year Study of Immediately Loaded Implants: 8-Patient Case Series Report.

The goal of this case series report is to demonstrate the predictability of providing immediate restorations with an implant specifically designed to achieve high primary stability, and to report on 12-month survival outcomes. Twenty-nine implants were placed in eight patients with various tooth-replacement needs, from single teeth to partially edentulous spans to fully edentulous mandibles. A new tapered-implant system (The Marc Nevins, Little Implant) was utilized that incorporates a self-tapping thread design with a thread pitch and thread lead to improve primary stability at insertion. All implants were placed with a minimum insertion torque of 45 Ncm. Four immediate implants and two early placements at extraction sites were included in the cohort. Twenty-seven implants were clinically successful at 1 year. Two implants in a healed ridge were found to have failed at 6 weeks postoperative in one patient wearing an ill-fitting removable partial denture. The radiographic crestal marginal bone levels were recorded in millimeters from the top of the implant platform to the first bone-to-implant contact. The mean crestal marginal bone level change was -0.57 ± 0.82 mm. This case series report demonstrates the ability of an implant designed for high primary stability to achieve successful integration in the presence of an immediate restoration for various clinical presentations, including single-tooth, multi-unit, and edentulous cases.

Effectiveness of a Flipped Classroom in Learning Periodontal Diagnosis and Treatment Planning.

The aim of this study was to assess whether a flipped classroom was an effective model for dental students to learn periodontal diagnosis and treatment planning (DTP). Participants were all third-year students in three academic years (2015-17) at Harvard School of Dental Medicine: two groups that experienced the flipped classroom (Classes of 2017 and 2018), and a control group (Class of 2019) that received the same content in traditional lecture format. All three groups completed a DTP knowledge quiz before and after the educational experience; the flipped classroom groups also completed pre and post surveys of their opinions about flipped classrooms. The flipped classroom group received a 23-minute video and corresponding PowerPoint presentation to view on their own time. In class, these students were divided into groups to diagnosis and treatment plan cases and discuss them with the instructor. Of 71 students in the two flipped classroom groups, 69 pre and post quizzes were returned (response rate 97%), and 61 pre and post surveys were returned (response rate 86%). Of 35 students in the lecture group, 34 completed pre and post quizzes (response rate 97%). The mean pre scores on the knowledge quiz in the flipped classroom groups and the conventional lecture group were 64% and 54%, respectively. After the DTP education, students' quiz scores improved in all three groups, but only the difference in the flipped classroom groups was statistically significant (p<0.01). After the flipped classroom session, 84% of the students agreed or strongly agreed that this methodology was effective for learning periodontal DTP, and 90% agreed or strongly agreed they understood the fundamentals of periodontal DTP-both increases over their pre survey scores. Overall, this flipped classroom model was effective in educating students on periodontal DTP and was well received by the students.

Defining recovery neurobiology of injured spinal cord by synthetic matrix-assisted hMSC implantation.

Mesenchymal stromal stem cells (MSCs) isolated from adult tissues offer tangible potential for regenerative medicine, given their feasibility for autologous transplantation. MSC research shows encouraging results in experimental stroke, amyotrophic lateral sclerosis, and neurotrauma models. However, further translational progress has been hampered by poor MSC graft survival, jeopardizing cellular and molecular bases for neural repair in vivo. We have devised an adult human bone marrow MSC (hMSC) delivery formula by investigating molecular events involving hMSCs incorporated in a uniquely designed poly(lactic-co-glycolic) acid scaffold, a clinically safe polymer, following inflammatory exposures in a dorsal root ganglion organotypic coculture system. Also, in rat T9-T10 hemisection spinal cord injury (SCI), we demonstrated that the tailored scaffolding maintained hMSC stemness, engraftment, and led to robust motosensory improvement, neuropathic pain and tissue damage mitigation, and myelin preservation. The scaffolded nontransdifferentiated hMSCs exerted multimodal effects of neurotrophism, angiogenesis, neurogenesis, antiautoimmunity, and antiinflammation. Hindlimb locomotion was restored by reestablished integrity of submidbrain circuits of serotonergic reticulospinal innervation at lumbar levels, the propriospinal projection network, neuromuscular junction, and central pattern generator, providing a platform for investigating molecular events underlying the repair impact of nondifferentiated hMSCs. Our approach enabled investigation of recovery neurobiology components for injured adult mammalian spinal cord that are different from those involved in normal neural function. The uncovered neural circuits and their molecular and cellular targets offer a biological underpinning for development of clinical rehabilitation therapies to treat disabilities and complications of SCI.

Using the Theory of Planned Behavior to Identify Predictors of Oral Hygiene: A Collection of Unique Behaviors.

BACKGROUND: This study aims to identify predictors of performed oral hygiene behaviors (OHBs) based on the Theory of Planned Behavior (TPB), oral health knowledge, and demographic factors. METHODS: Using a questionnaire, 381 participants in three general dental offices and one hospital dental department in York, Pennsylvania, were surveyed regarding performed OHB, attitudes, subjective norms, perceived behavioral control, oral health knowledge, income, age, and sex. RESULTS: Three unique elements of OHB were identified for analysis: brushing, interdental cleaning, and tongue cleaning. Regression analysis revealed that attitude was the strongest predictor of brushing behavior, followed by oral health knowledge, perceived behavior control, subjective norms, and income. Perceived behavior control was the strongest predictor of interdental cleaning, followed by increased age and attitude. Female sex was the strongest predictor of tongue cleaning, followed by subjective norms, decreased age, and perceived behavior control. Respectively, these three groups of predictive variables explained 22.5% of brushing behavior, 22.7% of interdental cleaning behavior, and 9.5% of tongue cleaning behavior. CONCLUSIONS: The present findings highlight the utility of viewing OHB as a set of unique behaviors with unique predictive variables and provide additional support for use of TPB in predicting OHB. Periodontal practitioners should consider the strong associations of attitude and perceived behavioral control with brushing and interdental cleaning behaviors when designing interventional efforts to improve patient home care.

A 10-year retrospective radiographic study of implantium dental implants.

A retrospective radiographic study was conducted from five private dental offices on patients requesting dental implant therapy to replace their missing teeth. All implants were placed and restored by early 2000, and patients were encouraged to continue their dental care at the same office. The records were reviewed and analyzed by the clinicians, who had more than 15 years of dental experience at the time of the initial patient treatment. A total of 74 patients with 242 implants were recalled up to 10 years (mean follow-up: 9.21 ± 1.7 years) after loading. There were five implant failures from this radiographic observation period, resulting in a 97.9% dental implant survival rate. The mean crestal bone level change on the mesial aspect was -0.36 ± 1.05 mm, while the mean crestal bone level change on the distal aspect was -0.18 ± 0.96 mm. Thus, the overall mean bone loss was -0.28 ± 0.05 mm. The dental implants, which had a sandblasted, large-grit, acid-etched surface, appeared to achieve successful osseointegration in this long-term observation period, and the implant system's unique design and surface features resulted in a stable osseous crest without bone loss to the first thread.

Stemness enhancement of human neural stem cells following bone marrow MSC coculture.

Rapid loss of stemness capacity in purified prototype neural stem cells (NSCs) remains a serious challenge to basic and clinical studies aiming to repair the central nervous system. Based on the essential role of mesodermal guidance in the process of neurulation, we hypothesized that coculture of human NSCs (hNSCs) with human bone marrow-derived mesenchymal stromal stem cells (hMSCs) could enhance the stemness of hNSCs through Notch-1 signaling. We have now tested the hypothesis by assessing behaviors of hNSCs and hMSCs under systematically designed coculture conditions relative to monocultures, with or without Notch-1 manipulation in vitro. Our data demonstrate that expression levels of Notch-1 and Hes-1 as determined by immunocytochemistry are significantly higher in hNSCs cocultured with hMSCs than those of controls. Furthermore, coculturing significantly increases immunoreactivity of CD15, a neural stemness marker, but decreases CD24, a marker of neural/neuronal commitment in hNSCs. The effect is independent from the physical status of cell growth since coculture and notch signaling actually promotes hNSC adhesion. Importantly, coculture with hMSCs markedly augments hNSC proliferation rate (e.g., higher yield in G2/M phase subpopulation in a notch-dependent manner detected by flow cytometry) without diminishing their lineage differentiation capabilities. The results suggest that coculture of hNSCs with hMSCs enhances stemness biology of hNSCs partially via activation of Notch-1 signal transduction. Our finding sheds new light on mesoderm-ectoderm cell fate determination via contact-based hMSC-hNSC interactions and provides mechanistic leads for devising effective regimens to sustain and augment stemness of in vitro established hNSC and hMSC lines for basic science, translational and clinical applications.

Efficacy of growth factor in promoting early osseointegration.

A preclinical study was conducted to evaluate the feasibility of 2 different topical formulations of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to promote early osseointegration and enhanced bone-to-implant contact (BIC) for dental implants placed in an edentulous ridge. Six female beagle dogs were divided into 3 groups. The control group included 4 implants with no coating; test group A included 10 implants with commercially available rhPDGF-BB formulation coating; and second test group B included 10 implants with prototype viscous rhPDGF-BB coating. Three dogs were sacrificed at 3 weeks (12 implants) and the remaining 3 dogs at 6 weeks after implant placement (12 implants). The specimens were retrieved for histological evaluation, and revealed an uneventful healing of all implants without any sign of an inflammatory response at the different time intervals. Furthermore, the bone was in very close contact with the implants' surfaces with no evidence of intervening fibrous tissue layers. At 3 weeks, new bone formation between most implant threads on rhPDGF-BB coated implants was evident, whereas in the control group only a thin and sparse amount of new bone was noted. At 6 weeks, the commercially available rhPDGF-BB formulation coated implant group (Group A) showed more trabecular bone and higher BIC compared to the other 2 groups. Histologically, the results in this study showed that use of conventionally available rhPDGF-BB formulation as the implant surface treatment may accelerate the process of osseointegration and enhance BIC.

A prospective 9-month human clinical evaluation of Laser-Assisted New Attachment Procedure (LANAP) therapy.

This investigation was designed and implemented as a single-center, prospective study to evaluate the clinical response to the Laser-Assisted New Attachment Procedure (LANAP). Eight patients with advanced periodontitis were enrolled and treated with full-mouth LANAP therapy and monitored for 9 months. Fullmouth clinical measurements, including clinical attachment level (CAL), probing depth (PD), and recession, were provided at baseline and after 9 months of healing by a single calibrated examiner, including a total of 930 sites and 444 sites with initial PD equal to or greater than 5 mm. Clinical results for the 930 sites measured pre- and postoperatively revealed that mean PD was reduced from 4.62 ± 2.29 mm to 3.14 ± 1.48 mm after 9 months (P < .05). CAL decreased from 5.58 ± 2.76 mm to 4.66 ± 2.10 mm (P < .05) and recession increased from 0.86 ± 1.31 mm to 1.52 ± 1.62 after 9 months (P < .05). For the subset of 444 sites with initial PD greater than or equal to 5 mm, the PD decreased from 6.50 ± 2.07 mm to 3.92 ± 1.54 mm (P < .05) and CAL decreased from 7.42 ± 2.70 mm to 5.78 ± 2.06 mm (P < .05). As demonstrated by the clinical evaluation, the majority of treated sites demonstrated clinical improvement. LANAP therapy should be further investigated with long-term clinical trials to compare the stability of clinical results with conventional therapy.

A prospective, randomized controlled preclinical trial to evaluate different formulations of biphasic calcium phosphate in combination with a hydroxyapatite collagen membrane to reconstruct deficient alveolar ridges.

Many patients and clinicians would prefer a synthetic particulate bone replacement graft, but most available alloplastic biomaterials have limited osteogenic potential. An alloplast with increased regenerative capacity would be advantageous for the treatment of localized alveolar ridge defects. This prospective, randomized controlled preclinical trial utilized 6 female foxhounds to analyze the osteogenic impact of different formulations of biphasic calcium phosphate (BCP) in combination with an hydroxyapatite-collagen membrane and their ability to reconstruct deficient alveolar ridges for future implant placement. The grafted sites were allowed to heal 3 months, and then trephine biopsies were obtained to perform light microscopic and histomorphometric analyses. All treated sites healed well with no early membrane exposure or adverse soft tissue responses during the healing period. The grafted sites exhibited greater radiopacity than the surrounding native bone with BCP particles seen as radiopaque granules. The graft particles appeared to be well-integrated and no areas of loose particles were observed. Histologic evaluation demonstrated BCP particles embedded in woven bone with dense connective tissue/marrow space. New bone growth was observed around the graft particles as well as within the structure of the graft particulate. There was intimate contact between the graft particles and newly formed bone, and graft particles were bridged by the newly formed bone in all biopsies from the tested groups. The present study results support the potential of these BCP graft particulates to stimulate new bone formation. Clinical studies are recommended to confirm these preclinical findings.

The clinical and histologic outcome of dental implant in large ridge defect regenerated with alloplast: a randomized controlled preclinical trial.

A basic tenet of successful osseointegration is that the implant resides in a sufficient quality and quantity of bone to ensure bone contact and thus stabilization. A prospective, randomized controlled preclinical trial was conducted to evaluate the bone-to-implant contact (BIC) when placing implants in bone regenerated by 3 different combinations of biphasic calcium phosphate (BCP). Dental implants were placed into the regenerated ridges of 6 female foxhounds; the ridges were reconstructed with different formulations of BCP in combination with an hydroxyapatite collagen membrane. They were retrieved after 3 months to perform light microscopic and histomorphometric analyses. Implants in each group appeared to be stable and osseointegrated. Light microscopic evaluation revealed tight contacts between the implant threads with the surrounding bone for all 4 groups. The mean BIC ranged from 64.7% to 73.7%. This preclinical trial provided clinical and histologic evidence to support the efficacy of all 3 formulations of BCP to treat large alveolar ridge defects to receive osseointegrated dental implants.

Human clinical and histologic evaluation of laser-assisted new attachment procedure.

This investigation was designed to evaluate the healing response to the laser-assisted new attachment procedure (LANAP). Eight patients presenting with 12 teeth predetermined to be surgically extracted were enrolled and consented to treatment with full-mouth LANAP therapy. LANAP surgical therapy consisted of a first pass with a 360-Μm fiber diameter, laser settings with verified output of 4.0 W and energy density of 1,965 mJ/mm2, 100-Μs pulse duration, and 20 Hz applied from the gingival margin to the base of the pocket parallel to the root surface and moved laterally and apically to remove the diseased pocket epithelium. The teeth were aggressively scaled and root planed with piezo ultrasonic instrumentation. A second pass was performed with a 360-Μm fiber diameter, laser settings with verified output of 4.0 W and energy density of 1,965 mJ/mm2, 650-Μs pulse duration, and 20 Hz applied from the apical extent of the bone defect to the gingival margin. After 9 months of healing, en bloc biopsy extractions were provided. Ten teeth were analyzed histologically to assess the periodontal wound healing. Five teeth evidenced a degree of periodontal regeneration with new cementum, periodontal ligament, and alveolar bone. One tooth had new attachment with new cementum and inserting collagen fibers, and four teeth healed via a long junctional epithelium. LANAP therapy should be further investigated with long-term clinical trials to compare the stability of clinical results to conventional therapy. This report provides evidence that LANAP therapy can induce periodontal regeneration.

The combination of purified recombinant human platelet-derived growth factor-BB and equine particulate bone graft for periodontal regeneration.

BACKGROUND: The objective of this study is to evaluate the potential for periodontal regeneration of a critical-sized defect with the application of recombinant human platelet-derived growth factor (rhPDGF-BB) combined with either a particulate equine or a ß-tricalcium phosphate (ß-TCP) matrix. METHODS: Critical-sized intrabony 2-wall defects were created bilaterally on the distal surface of the second premolar and the mesial surface of the first molar in nine hounds. Twelve defects received rhPDGF-BB/equine treatment, 12 defects received rhPDGF-BB/ß-TCP treatment, and the remaining 12 sites served as sham-surgery controls. The animals were sacrificed after a 10-week healing period. RESULTS: Clinical healing was uneventful without obvious signs of overt gingival inflammation. Histologic and histomorphometric analyses revealed statistically that there were differences among the three groups in terms of new bone formation (P <0.001). The amount of test material for both rhPDGF-BB/equine and rhPDGF-BB/ß-TCP groups was comparable, but the amount of newly formed bone was significantly higher (P <0.01) in favor of the rhPDGF-BB/equine group. The amount of new cementum formed for the rhPDGF-BB/equine group (4.8 ± 1.3 mm) was significantly higher (P =0.001) than the sham-surgery control group (1.7 ± 1.9 mm). CONCLUSION: Both rhPDGF-BB/equine and rhPDGF-BB/ß-TCP have the potential to support the regeneration of the periodontal attachment apparatus.

The influence of different implant materials on human gingival fibroblast morphology, proliferation, and gene expression.

PURPOSE: The aim of this study was to investigate the cellular response of human gingival fibroblasts (HGFs) cultured on smooth or rough zirconia (Zr) or titanium (Ti) disks. MATERIALS AND METHODS: Disks fabricated from four different materials--smooth Zr (Zr-S), rough Zr (Zr-R), smooth Ti (Ti-S), and rough Ti (Ti-R)--were used, and surface roughness was analyzed by atomic force microscopy. After HGFs were cultured on these disks, cell morphology was examined by scanning electron microscopy, cell proliferation activity was evaluated by a monotetrazolium assay, and gene expression levels of various collagens and integrins were measured by real-time polymerase chain reaction. RESULTS: The Ti-R disks were the roughest, followed by Zr-R, Ti-S, and Zr-S, in that order. The cells cultured on the Zr-S and Ti-S disks appeared to be more aligned with the fine irregularities at later time points, whereas the cells cultured on the Zr-S showed the weakest spreading compared to the other surfaces after 3 hours of culture. With respect to proliferation, cells proliferated significantly faster on the Zr-S surface than on the other surfaces. Gene expression of integrin α2 at 3 hours and integrin α5 and type I collagen at 48 hours on Zr-S was significantly up-regulated compared to Ti. Conversely, the expression of integrins ß1 and ß3 and type III collagen was significantly decreased on Zr-S at 1 hour compared to the other materials. CONCLUSION: These data indicate that different surface materials and topographies may induce a distinct HGF morphology, proliferation, and gene expression.

The use of mucograft collagen matrix to augment the zone of keratinized tissue around teeth: a pilot study.

This prospective split-mouth pilot case series compared the use of a bilayer collagen matrix (CM) to an autogenous gingival graft (AGG) in the ability to increase the zone of keratinized attached gingiva. Five patients with inadequate amounts of keratinized attached gingiva bilaterally in the posterior mandible were enrolled using a split-mouth design. There were statistically significant increases in attached gingiva at all test (CM) and control (AGG) sites. The CM sites at 12 months blended well with surrounding tissues, while the AGG sites were morphologically dissimilar to the adjacent areas. Biopsy results showed intrapatient histologic similarity between CM and AGG treatments, with all sites exhibiting mature connective tissue covered by keratinized epithelium. Thus, the obtained data support further investigations in evaluating the role of CM as a viable alternative to AGG in augmenting areas deficient in keratinized gingiva.