Factors Associated with Increased Healing Time in Complete Femoral Fractures After Long-Term Bisphosphonate Therapy.

BACKGROUND: The purpose of this study was to analyze factors that affect healing time after operative treatment of complete femoral fractures associated with long-term use of bisphosphonates. In particular, we sought to determine surgically controllable factors related to fracture-healing time. METHODS: Ninety-nine consecutive patients (109 fractures) who had been surgically treated for a complete atypical femoral fracture were enrolled. All patients had a documented history of bisphosphonate therapy at the time of presentation, with an average duration of 7.4 ± 3.5 years (range, 3 to 20 years). Baseline demographic data, characteristics of the fracture and surgery, and radiographic findings including femoral neck-shaft angle, coronal and sagittal bowing of the femur, and thickness of the femoral cortex were examined. Univariate and multivariate logistic regression analyses were performed to identify predictive factors associated with delayed union or nonunion. RESULTS: Of the 109 fractures, 76 (69.7%) showed osseous union within 6 months after the index surgery and were assigned to the successful healing group. The remaining 33 fractures (30.3%), which showed delayed union or nonunion, were assigned to the problematic healing group. There were differences in body mass index (BMI), bisphosphonate therapy duration, and the rate of prodromal symptoms between the 2 groups. Supra-isthmic fracture location, femoral bowing of ≥10° in the coronal plane, and a lateral/medial cortical thickness ratio of ≥1.4 were predictive of problematic healing but were uncontrollable factors. Iatrogenic cortical breakage around the fracture site as well as a ratio of ≥0.2 between the remaining gap and the cortical thickness on the anterior and lateral sides of the fracture site were controllable predictive factors associated with problematic healing. CONCLUSIONS: Intramedullary nailing without cortical breakage around the fracture site and decreasing the anterior and lateral fracture gaps (avoidance of distraction) as much as possible are recommended to reduce healing time in complete femoral fractures associated with long-term use of bisphosphonates. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Non-thermal atmospheric pressure plasma increased mRNA expression of growth factors in human gingival fibroblasts.

OBJECTIVES: The aim of this in vitro study was to investigate the effects of a non-thermal atmospheric pressure plasma jet (NTAPPJ) on the cellular activity of human gingival fibroblasts (HGF) for possible non-surgical application of it during gingival wound healing. MATERIALS AND METHODS: HGF cells were exposed with NTAPPJ for 1, 2, and 4 min and were investigated for cellular attachment, cell viability, morphology of attached cells, proliferation rate, and messenger ribonucleic acid (mRNA) expression of various growth factors. Also, scavengers for chemicals produced by NTAPPJ were used to identify the chemical species responsible for the effects. RESULTS: There was no significant change in the number of HGF cells attached or their proliferation following NTAPPJ exposure. Also, high cell viability resulted from exposure of all of HGF cells to NTAPPJ for 1, 2, and 4 min. However, cells were more stretched while the mRNA expressions of transforming growth factor and vascular endothelial growth factor were significantly increased following NTAPPJ exposure. Additionally, the scavenger test showed that nitric oxide is likely to be the chemical responsible for an increase of cellular activity. CONCLUSION: The results demonstrated that the NTAPPJ increased mRNA expressions of growth factors in human gingival fibroblasts. CLINICAL RELEVANCE: Application of NTAPPJ would be useful in gingival wound healing in clinics though additional studies confirming the effects would be needed.

Incidence and Factors Predicting Venous Thromboembolism After Surgical Treatment of Fractures Below the Hip.

OBJECTIVES: This study was designed to investigate the incidence and risk factors of postoperative venous thromboembolism (VTE) in a series of patients with fractures below the hip. In addition, we sought to examine the rates of VTE before and after introduction of thromboprophylaxis. DESIGN: Retrospective review. SETTING: University-based academic medical center. PATIENTS: Nine hundred one consecutive patients met the inclusion criteria. Of the 901 patients, 337 (37.4%) were treated before the initiation of institutional guidelines for thromboprophylaxis and 564 (62.6%) received thromboprophylaxis in accordance with our hospitalization protocol. INTERVENTION: Surgical intervention for fractures occurring in the lower extremity below the hip. MAIN OUTCOME MEASUREMENTS: Symptomatic thromboembolic events within 90 days of surgery and risk factors of postoperative VTE. RESULTS: Of the 901 patients, 25 (2.7%) had confirmed symptomatic deep vein thrombosis and 13 (1.4%) had symptomatic pulmonary embolism. The overall incidence of symptomatic VTE was significantly different between the patients not receiving thromboprophylaxis (6.8%; 23 of 337) and those receiving thromboprophylaxis (2.3%; 13 of 564). Of the 31 variables tested for an association with VTE, an advanced age of more than 60 years, cardiovascular disease, and chronic lung disease were independent risk factors. CONCLUSIONS: Clinically detectable VTE in fractures of the lower extremity below the hip are not uncommon, and thromboprophylaxis seemed to decrease the incidence of postoperative VTE. LEVEL OF EVIDENCE: Prognostic Level II. See the guidelines for authors for a complete description of levels of evidence.

Monogeneans (Platyhelminthes) from marine fishes of Tongyeong, Korea.

Monogeneans (Platyhelminthes) mostly parasitize on fins, skin and gills of fishes. In Korea, the study on monogeneans is limited, although, fishes are frequently encountered with severe infection of monogeneans. Hence, some of ranched and wild fishes were collected from Tongyeong marine living resources research and conservation center, southern part of Korea to screen and understand the infection of monogeneans. All three fish hosts were found with the infection of monogeneans including five species from four different families. They are: (1) Anoplodiscus spari Yamaguti (Publ Seto Mar Biol Lab Kyoto Univ 7:53-88, 1958) (Anoplodiscidae) from the fins and body surface of blackhead seabream Acanthopagrus schlegelii schlegelii (Bleeker); (2) A. tai Ogawa (Fish Pathol 29:5-10, 1994) from the fins of red seabream Pagrus major (Temminck and Schlegel); (3) Benedenia sekii Yamaguti (Studies on the helminth fauna of Japan. Part 19. Fourteen new ectoparasitic trematodes of fishes. Published by the author, Kyoto, 1937), Meserve (Rep Allan Hancock Paci Exped (1932-1937) 2:31-89, 1938) (Capsalidae) from the body surface of P. major; (4) Choricotyle elongata Goto (J Coll Sci Imp Univ Tokyo 8:1-273, 1894) (Diclidophoridae) from the gills of P. major; (5) Udonella fugu Freeman and Ogawa (Int J Parasitol 40:255-264, 2010) (Udonellidae) hyperparasitized on the body of parasitic copepod Pseudocaligus fugu (Yamaguti 1936) (Caligidae) infecting the wild grass puffer Takifugu niphobles (Jordan and Snyder). Capsalids are commonly reported in Korea, except B. sekii, however, other reported genera are uncommon. Hence, all reported monogeneans are considered as a first record from Korea.

Standard versus over-tensioning in the transfer of extensor indicis proprius to extensor pollicis longus for chronic rupture of the thumb extensor.

PURPOSE: The purpose of this study was to evaluate the functional outcomes of the over-tensioning technique compared with those of the standard tensioning technique in the transfer of extensor indicis proprius (EIP) to extensor pollicis longus (EPL) for the chronic rupture of the thumb extensor. METHODS: Data were collected from patients who underwent tendon transfer using EIP between March 2003 and August 2011. 23 were treated with the standard tensioning technique and 25 patients (Group B) with the over-tensioning technique. While standard tension was maintained with the thumb in full extension and the wrist in 30° of flexion, over-tension was maintained with the thumb in full extension and the wrist in the neutral position. All patients were assessed for total range of motion, elevation and flexion deficit, the thumb grip and pinch strength, and the thumb and the index extension strength compared to the unaffected side, EIP-EPL evaluation as suggested by Lemmen et al. and Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH). RESULTS: Group A: total range of motion 115°, elevation deficit 2.0 cm, combined flexion deficit 1.0 cm, thumb extension strength 75%, thumb grip strength 91%, and pinch strength 87%. Functional outcomes were 13 excellent, 6 good, 3 fair, and 1 poor. Median DASH score was 21.3 points. Group B: total range of motion 125°, elevation deficit 1.0 cm, combined flexion deficit 1.5 cm, thumb extension strength 85%, thumb grip strength 88%, and pinch strength 83%. Functional outcomes were 16 excellent, 7 good, 2 fair, and 0 poor. Median DASH score was 19.8 points. There are significant differences in the range of motion, elevation deficit, and extension strength of thumb between the two groups (p=.001, p=.001, and p=.028, respectively). CONCLUSION: While the functional outcomes of both groups were favorably acceptable in a majority of the patients, there were significant differences in aspects of range of motion, elevation deficit, and strength of the thumb between both groups. LEVEL OF EVIDENCE: Case-control study, Level III.

Impact of different synthetic bone fillers on healing of extraction sockets: an experimental study in dogs.

OBJECTIVES: The objective of this study was to elucidate the socket healing process and biodegradation of incorporating synthetic bone fillers followed by grafting of the fresh extraction socket. MATERIALS AND METHODS: Third premolars in four quadrants of eight beagle dogs were extracted and randomly treated with either one of hydroxyapatite (HA), biphasic calcium phosphate (BCP), ß-tricalcium phosphate (ß-TCP), or no graft (C). Histologic observations and histomorphometric analysis at three zones (apical, middle, and coronal) of the socket were performed. Socket area (S) and the proportions of newly formed bone (%NB), residual biomaterials (%RB), and fibrovascular connective tissue (%FCT) at 2, 4, and 8 weeks were measured. The numbers of osteoclast-like multinucleated cells (No.OC) were also determined at the three zones. RESULTS: %NB was significantly higher in control group compared with the grafted groups at all healing periods. %NB of HA and BCP increased with time, whereas %RB showed different patterns that decreased in BCP, unlike the minimal change observed in HA. %NB of ß-TCP showed smallest portion compared with other grafted groups at 2 and 4 weeks, however, significantly increased at 8 weeks. %RB of ß-TCP was less than HA and BCP at all healing periods. Numbers of multinucleated cells were greater in BCP and ß-TCP, followed by HA and smallest in control group. CONCLUSIONS: Within the limit of this study, bone formation of the extraction socket was delayed in the sockets grafted with synthetic bone fillers and showed different healing process according to the biodegradation patterns.

Comparison between a ß-tricalcium phosphate and an absorbable collagen sponge carrier technology for rhGDF-5-stimulated periodontal wound healing/regeneration.

BACKGROUND: The objective of this study is to compare a candidate ß-tricalcium phosphate (ß-TCP) carrier technology with the absorbable collagen sponge (ACS) benchmark to support recombinant human growth/differentiation factor-5 (rhGDF-5)-stimulated periodontal wound healing/regeneration. METHODS: Routine, bilateral, critical-size (5-mm), 1-wall, intrabony periodontal defects were surgically created in the mandibular premolar region in 10 beagle dogs. Five animals received rhGDF-5/ß-TCP and five animals received rhGDF-5/ACS, with a total of 20 µg rhGDF-5 per defect. The animals were euthanized for histologic and histometric analyses at 8 weeks postsurgery. RESULTS: Both rhGDF-5/ACS and rhGDF-5/ß-TCP stimulated the formation of functionally oriented periodontal ligament, cellular mixed fiber cementum, and woven/lamellar bone. Bone regeneration (height and area) was significantly greater for the rhGDF-5/ß-TCP construct than for the rhGDF-5/ACS (3.26 ± 0.30 mm versus 2.22 ± 0.82 mm, P <0.01; and 10.45 ± 2.26 mm(2) versus 5.62 ± 2.39 mm(2), P <0.01, respectively). Cementum formation ranged from 3.83 ± 0.73 mm to 3.03 ± 1.18 mm without significant differences between groups. Root resorption/ankylosis was not observed. CONCLUSIONS: The ß-TCP carrier technology significantly enhanced rhGDF-5-stimulated bone formation compared with the ACS benchmark in this discriminating periodontal defect model. The structural integrity of the ß-TCP carrier, preventing compression while providing a framework for bone ingrowth, may account for the observed results.

Maturation of alveolar bone following implantation of an rhGDF-5/PLGA composite into 1-wall intra-bony defects in dogs: 24-week histometric observations.

OBJECTIVE: The aim of this study was to evaluate long-term (24 weeks) alveolar bone maturation following surgical application of recombinant human growth/differentiation factor-5 (rhGDF-5) in an injectable poly-lactide-co-glycolide-acid (PLGA) composite carrier using an established periodontal defect model. METHODS: Routine, bilateral, 4 × 5 mm (width × depth), 1-wall, critical-size, intra-bony periodontal defects were surgically created at the 2nd and 4th mandibular premolar teeth in 10 Beagle dogs. The animals were randomized to receive (split-mouth design; defect sites in the same jaw quadrant getting the same treatment) rhGDF-5/PLGA high dose (188 µg/defect) versus sham-surgery control (5 animals), and rhGDF-5/PLGA low dose (37 µg/defect) versus carrier control (5 animals). The animals were euthanized for histometric analysis following a 24-week healing interval. RESULTS: Clinical healing was uneventful. The rhGDF-5 high dose significantly increased bone formation compared with controls in terms of bone area (p < 0.05), and a high degree of bone maturation was observed in the rhGDF-5/PLGA high dose group. Root resorption/ankylosis or other aberrant healing events were not observed. CONCLUSION: The rhGDF-5/PLGA appears to support alveolar bone healing/regeneration and the rhGDF-5/PLGA high dose uniquely increased maturation of the regenerated bone.

Maturation of periodontal tissues following implantation of rhGDF-5/ß-TCP in one-wall intra-bony defects in dogs: 24-week histological observations.

OBJECTIVE: Although a previous study reported that recombinant human growth/differentiation factor-5 (rhGDF-5) coated onto a ß-tricalciumphosphate (ß-TCP) significantly enhanced periodontal regeneration, the long-term stability/maturation of the regenerated tissues has not been demonstrated. The objective of this study was to evaluate periodontal regeneration/maturation following application of rhGDF-5/ß-TCP using an established periodontal defect model and a 24-week healing interval. MATERIAL & METHODS: Unilateral, surgically created, 4 × 4 × 5 mm (length × width × height), one-wall, critical-size, intra-bony periodontal defects at the mandibular second and fourth premolar teeth in five young adult Beagle dogs received rhGDF-5/ß-TCP. Bilateral sites at the fourth premolar in the other four dogs served as pristine controls receiving mucogingival flap surgery without defect induction. The animals were euthanized at 24 weeks for histological analysis. Unpublished data from the previous 8-week study were used to compare tissue maturation between 8 and 24 weeks. RESULTS: Linear histometric observations of cementum and alveolar regeneration showed no significant differences between the 8- and 24-week observation intervals. However, parameters of periodontal tissue maturation showed significant differences between the observation intervals including increased fraction mineralized tissue and lamellar bone (p < 0.05) and decreased osteocyte counts (p < 0.05) at 24 weeks compared with 8 weeks. Although the count inserting Sharpey's fibre did not significantly change, regenerated cementum remote from the intact periodontal ligament appeared more highly mineralized and thicker at 24 weeks compared with 8 weeks, and compared with the pristine cementum. Minimal ß-TCP remained. CONCLUSIONS: These 24-week observations suggest that regenerated periodontal tissues in sites receiving rhGDF-5/ß-TCP undergo progressive maturation without debilitating aberrant tissue reactions.

An arthroscopic pleated capsular shift for recurrent anterior dislocation of the shoulder.

PURPOSE: This study examined the clinical results of an arthroscopic simple pleated capsular shift to treat severe recurrent anterior dislocation of the shoulder. METHODS: Twenty-four patients with anterior labroligamentous periosteal sleeve avulsion or advanced lesions who underwent an arthroscopic simple pleated capsular shift were included in this study. To create an arthroscopic simple pleated capsular shift, redundant capsules, including glenohumeral ligaments, were brought at least 1 cm lateral and 1 cm inferior and shifted to the prepared glenoid. Four sutures were made at the 5, 4, 3, and 1-2 o'clock positions with four anchors. Clinical results were evaluated using a visual analog scale (VAS), ROWE scores, active motion, and return to activity. Statistical analyses were carried out using paired t tests. RESULTS: Three out of 24 patients had complaints. Two patients with recurrent instability underwent a repeat surgery, while the other patient complained of a stiff shoulder. There was a significant improvement in the VAS and ROWE scores post-operatively versus pre-operatively (p < 0.001, p < 0.001, respectively), but no significant differences in active motion except for external rotation, which decreased post-operatively (p = 0.02). CONCLUSIONS: In patients with severe recurrent anterior dislocation, simple pleated capsular shift provided a reliable result. Four capsular shift sutures, 1 cm lateral and 1 cm inferior from the glenoid, were sufficient to reduce shoulder joint volume and restore stability. The arthroscopic capsular shift could be an alternative method in the case of no available labral lesion for repair. LEVEL OF EVIDENCE: Case series, Therapeutic, Level IV.

Modified cytotoxicity evaluation of elastomeric impression materials while polymerizing with reduced exposure time.

OBJECTIVE: Cytotoxicity evaluation is an important step in biocompatibility assessment of dental impression materials. Previously, cytotoxicity evaluations were carried out on already set ('set') impression materials for contact time or extraction time of 24 h or longer in duration. However, clinically, dental impression materials are in contact with oral tissue while they are being set ('polymerizing'), for no longer than 10 min. Hence, the aim of this study was to investigate the difference in results between 'polymerizing' and 'set' forms of impression materials as well as the difference in results between longer duration of contact or extraction time (12 or 24 h) and shorter duration of time (15 or 30 min). MATERIALS AND METHODS: Seven dental impression materials of different chemical compositions were tested. Two commonly used in vitro tests were used-test on extraction and test by direct contact. Both 'polymerizing' and 'set' forms of impression materials were used with different durations of extraction and contact (15 min, 30 min, 12 h and 24 h). RESULTS: There were significant (p < 0.05) differences of cell viability and cell proliferation between the 'polymerizing' and 'set' impression materials. Also, significant (p < 0.05) differences were noted with variance in duration of time. CONCLUSION: In light of the results, it is recommended to use a 'polymerizing' state of dental impression material for cytotoxicity evaluation, with 15 or 30 min of contact between cell and dental impression materials and an extraction time of 15 or 30 min that is more reflective of clinical situations.

Dimensional change of the healed periosteum on surgically created defects.

PURPOSE: The final goal of regenerative periodontal therapy is to restore the structure and function of the periodontium destroyed or lost due to periodontitis. However, the role of periosteum in periodontal regeneration was relatively neglected while bone repair in the skeleton occurs as a result of a significant contribution from the periosteum. The aim of this study is to understand the histological characteristics of periosteum and compare the native periosteum with the repaired periosteum after elevating flap or after surgical intervention with flap elevation. METHODS: Buccal and lingual mucoperiosteal flaps were reflected to surgically create critical-size, "box-type" (4 mm width, 5 mm depth), one-wall, intrabony defects at the distal aspect of the 2nd and the mesial aspect of the 4th mandibular premolars in the right and left jaw quadrants. Animals were sacrificed after 24 weeks. RESULTS: THE RESULTS FROM THIS STUDY ARE AS FOLLOWS: 1) thickness of periosteum showed difference as follows (P<0.05): control group (0.45±0.22 mm)>flap-elevation group (0.36±0.07 mm)>defect formation group (0.26±0.03 mm), 2) thickness of gingival tissue showed difference as follows (P<0.05): defect formation group (3.15±0.40 mm)>flap-elevation group (2.02±0.25 mm)>control group (1.88±0.27 mm), 3) higher cellular activity was observed in defect formation group and flap-elevation groups than control group, 4) the number of blood vessles was higher in defect formation group than control group. CONCLUSIONS: In conclusion, prolonged operation with increased surgical trauma seems to decrease the thickness of repaired periosteum and increase the thickness of gingiva. More blood vessles and high cellular activity were observed in defect formation group.

Effect of seeding using an avidin-biotin binding system on the attachment of periodontal ligament fibroblasts to nanohydroxyapatite scaffolds: three-dimensional culture.

PURPOSE: For periodontal tissue engineering, it is a primary requisite and a challenge to select the optimum types of cells, properties of scaffold, and growth factor combination to reconstruct a specific tissue in its natural form and with the appropriate function. Owing to fundamental disadvantages associated with using a two-dimensional substrate, several methods of seeding cells into three-dimensional scaffolds have been reported and the authors have asserted its usefulness and effectiveness. In this study, we explore the cell attachment of periodontal ligament fibroblasts on nanohydroxyapatite (n-HA) scaffold using avidin biotin binding system (ABBS). METHODS: Human periodontal ligament fibroblasts were isolated from the health tooth extracted for the purpose of orthodontic procedure. HA nanoparticles were prepared and Ca(NO(3))(2)-4H(2)O and (OC(2)H(5))(3)P were selected as precursors of HA sol. The final scaffold was 8 mm in diameter and 3 mm in height disk with porosity value of 81.55%. 1×10(5) periodontal ligament fibroblasts were applied to each scaffold. The cells were seeded into scaffolds by static, agitating and ABBS seeding method. RESULTS: The number of periodontal ligament fibroblasts attached was greater for ABBS seeding method than for static or agitating method (P<0.05). No meaningful difference has been observed among seeding methods with scanning electron microscopy images. However, increased strength of cell attachment of ABBS could be deduced from the high affinity between avidin and biotin (Kd=10(-15) M). CONCLUSIONS: The high-affinity ABBS enhances the ability of periodontal ligament fibroblasts to attach to three-dimensionally constructed n-HA scaffolds.

Wound healing/regeneration using recombinant human growth/differentiation factor-5 in an injectable poly-lactide-co-glycolide-acid composite carrier and a one-wall intra-bony defect model in dogs.

OBJECTIVE: The purpose of this study was to evaluate the effect of recombinant human growth/differentiation factor-5 (rhGDF-5) on periodontal wound healing/regeneration using an injectable poly-lactide-co-glycolide-acid (PLGA) composite carrier and an established defect model. METHODS: Bilateral 4 × 5 mm (width × depth) one-wall, critical-size, intra-bony periodontal defects were surgically created at the second and the fourth mandibular pre-molar teeth in 15 Beagle dogs. The animals were randomized to receive (using a split-mouth design; defect sites in the same jaw quadrant getting the same treatment) rhGDF-5 high dose (188 µg/defect) versus sham-surgery control (five animals), rhGDF-5 mid dose (37 µg/defect) versus carrier control (five animals), and rhGDF-5 low dose (1.8 µg/defect) versus treatment reported elsewhere (five animals). The animals were euthanized for histometric analysis following an 8-week healing interval. RESULTS: Clinical healing was uneventful. The rhGDF-5/PLGA construct was easy to assemble and apply. The rhGDF-5 high dose supported significantly increased bone formation compared with the low-dose, sham-surgery, and carrier controls (p<0.05) and induced significantly increased cementum formation compared with the controls (p<0.05). Root resorption/ankylosis or other aberrant healing events were not observed. CONCLUSION: rhGDF-5 appears to effectively support periodontal wound healing/regeneration in a dose-dependent order; the PLGA composite appears to be an effective ease-of-use candidate for carrier technology.

Mechanism of alveolar bone loss in a collagen-induced arthritis model in mice.

OBJECTIVE: the aim of this study was to understand the cellular/molecular mechanisms of periodontal breakdown in a collagen-induced arthritis (CIA) model in mice to enhance the understanding of rheumatoid arthritis (RA)-associated alveolar bone loss in humans. MATERIALS AND METHODS: all analyses were performed on paired samples from CIA and control group mice. Mandibles were retrieved for micro-computed tomography (micro-CT), histomorphometric analysis, and isolation of alveolar bone cells (ABCs). In vitro osteoclastogenic/osteogenic/adipogenic potentials of ABCs were evaluated and the mRNA expression of downstream effector genes was assessed. Bone formation of ABCs was assessed using an ectopic transplantation model. RESULTS: histomorphometric and micro-CT data showed that alveolar bone loss was significantly increased in the CIA group (p<0.05). Osteoclastogenesis was significantly increased in the CIA group in vivo (p<0.05), with upregulated mRNA expressions of osteoclastogenesis-associated genes. Osteoblasts appeared to undergo increased apoptosis, and the bone-forming activity of ABCs concomitantly decreased with in vitro osteogenic differentiation and in vivo ectopic transplantation (p<0.05). Also, adipogenesis-associated mRNA expression was highly expressed in the CIA group, resulting in significantly enhanced adipocyte differentiation in vitro (p<0.05). CONCLUSIONS: these data demonstrate that increased osteoclastic activity, decreased bone-forming activity and enhanced adipogenesis promote alveolar bone loss in a CIA model in mice, and they suggest that these mechanisms could account for the same outcome in human RA.

Evaluating intra- and inter-examiner reproducibility in histometric measurement: one-wall intrabony periodontal defects in beagle dogs.

PURPOSE: Accurate and exact measurement is an important factor for generating meaningful results in any properly designed study. If all the participating examiners are able to yield similar results, it will be possible to evaluate the objective results of the study more easily and quickly. The purpose of this study was to evaluate the intra- and inter-examiner reproducibility of histometric measurements in the intrabony periodontal defect model. METHODS: One wall intrabony defects were surgically created at the distal aspect of the second and the medial aspect of the fourth mandibular premolars in the right and left jaw quadrants in twenty beagle dogs and the defect sites received the following ß-tri calcium phosphate, growth differentiation factor-0, growth differentiation factor-100 and sham surgery. Histometric analysis was performed after 8 weeks. Histometric parameters were recorded and repeated at three months interval by three examiners. Intra- and inter-examiner reproducibility was assessed. RESULTS: Most parameters of all the groups showed high intra- and inter-examiner reproducibility. Parameters including defect height, bone regeneration height, cementum regeneration height, and formation of junctional epithelium yielded inter-examiner correlation ≥ 0.9. The intra-examiner reproducibility showed a high result, over 0.9. CONCLUSIONS: Histometric evaluation of the one-wall intra-alveolar periodontal defect model showed high reproducibility not only for a single given examiner but also among the three examiners.

A simple approach to preserve keratinized mucosa around implants using a pre-fabricated implant-retained stent: a report of two cases.

PURPOSE: There is no consensus regarding the relationship between the width of keratinized mucosa and the health of peri-implant tissues, but clinicians prefer to provide enough keratinized mucosa around dental implants for long-term implant maintenance. An apically positioned flap during second stage implant surgery is the chosen method of widening the keratinized zone in simple procedures. However, the routine suture techniques used with this method tend to apply tension over the provisional abutments and decrease pre-existing keratinized mucosa. To overcome this shortcoming, a pre-fabricated implant-retained stent was designed to apply vertical pressure on the labial flap and stabilize it in a bucco-apical direction to create a wide keratinized mucous zone. METHODS: During second stage implant surgery, an apically displaced, partial thickness flap with a lingualized incision was retracted. A pre-fabricated stent was clipped over the abutments after connecting to the provisional abutment. Vertical pressure was applied to displace the labial flap. No suture was required and the stent was removed after 10 days. RESULTS: A clinically relevant amount of keratinized mucosa was achieved around the dental implants. Buccally displaced keratinized mucosa was firmly attached to the underlying periosteum. A slight shrinkage of the keratinized zone was noted after the healing period in one patient, but no discomfort during oral hygiene was reported. Clinically healthy gingiva with enough keratinized mucosa was achieved in both patients. CONCLUSIONS: The proposed technique is a simple and time-effective technique for preserving and providing keratinized tissue around dental implants.

Growth/differentiation factor-5 significantly enhances periodontal wound healing/regeneration compared with platelet-derived growth factor-BB in dogs.

OBJECTIVE: Recombinant human growth/differentiation factor-5 (rhGDF-5) in a particulate beta-tricalcium phosphate (beta-TCP) carrier is being evaluated to support periodontal regeneration. The objective of this study was to evaluate periodontal wound healing/regeneration following an established clinical (benchmark) protocol including surgical implantation of rhGDF-5/beta-TCP in comparison with that following implantation of recombinant human platelet-derived growth factor-BB (rhPDGF) combined with a particulate beta-TCP biomaterial using an established canine defect model. MATERIALS AND METHODS: Bilateral, 4 x 5 mm (width x depth), one-wall, critical-size, intrabony periodontal defects were surgically created at the mandibular second and fourth pre-molar teeth in five adult Beagle dogs. Defect sites were randomized to receive rhGDF-5/beta-TCP or the rhPDGF construct followed by wound closure for primary intention healing. The animals were sacrificed following an 8-week healing interval for histological and histometric examination. RESULTS: Clinical healing was generally uneventful. Sites receiving rhGDF-5/beta-TCP exhibited a significantly enhanced cementum formation compared with sites receiving the rhPDGF construct, averaging (+/-SD) 4.49+/-0.48 versus 2.72+/-0.91 mm (p<0.001). Similarly, bone regeneration height and area were significantly enhanced at sites receiving rhGDF-5/beta-TCP versus that of the rhPDGF construct averaging, 3.08+/-0.74 versus 1.29+/-0.78 mm (p<0.001) and 6.03+/-1.28 versus 2.98+/-2.61 mm(2) (p<0.01), respectively. Cementum regeneration included cellular/acellular mixed (extrinsic/intrinsic) fibre cementum at sites receiving rhGDF-5/beta-TCP; sites receiving the rhPDGF/beta-TCP showed a pre-dominantly acellular cementum. Newly formed cementum generally extended above the adjoining alveolar bone. Both protocols displayed beta-TCP residues apparently undergoing resorption. Application of both materials appears safe, as they were associated with limited, if any, adverse events. CONCLUSION: rhGDF-5/beta-TCP shows a significant potential to support/accelerate periodontal wound healing/regeneration. Application of rhGDF-5/beta-TCP appears safe and should be further evaluated in human clinical trials.

Effect of conical configuration of fixture on the maintenance of marginal bone level: preliminary results at 1 year of function.

OBJECTIVES: To evaluate and to compare the effect of the conical neck design on marginal bone loss around the fixtures, when both implants were provided with micro-threads to the top of the fixture. MATERIALS AND METHODS: Two types of implant, one with a straight shape (S) and the other with a conical neck design (C) provided with a retentive element to the top of the fixture, were placed adjacent to each other in the partially edentulous areas of 12 patients. Bone loss around each implant was analyzed after 1 year of functional loading. The bone losses after loading were compared using Wilcoxon's signed-rank test. RESULTS: The mean marginal bone losses (S, 0.05 + or - 0.09 mm; C, 0.07 + or - 0.14 mm) were not statistically significant between the two groups (P=0.578). CONCLUSIONS: There was no significant difference between conical and straight neck implants in terms of marginal bone loss after 1 year of loading.