Effects of enamel matrix derivatives on the proliferation and the release of growth factors of human periodontal ligament cells / 대한치과보철학회지

PURPOSE: Stimulating the proliferation and migration of periodontal ligament cells (PDLCs) has become the main goal of periodontal regeneration. To accomplish this goal, regeneration procedures have been developed, but results have not been predictable. Recently, tissue engineering using enamel matrix derivatives (EMDs) and growth factors has been applied to periodontal regeneration; however, the mechanism of EMDs is largely unknown. The aim of this study was to investigate the effects of EMDs on the proliferation and release of growth factors from PDLCs. MATERIALS AND METHODS: Human PDLCs were removed from individually extracted 3rd molars of healthy young adults, and cultured in the media containing EMDs (Emdogain, Biora, Malmo, Sweden) at concentration of 0, 12.5, 25, 50, 100, and 200 µg/mL each. Cell proliferation and ALP (alka-line phosphatase) activity were measured. The evaluation of growth factors released by PDLCs was also performed by one-way analysis of variance (ANOVA) and Bonferroni's multiple comparison test. RESULTS: Significantly increased proliferation and ALP activity were observed in PDLCs treated with over 25 µg/mL and 50 µg/mL EMDs, respectively. Additionally, treatment of PDLCs with 50 µg/mL resulted in significantly increased release of vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β after 24 h and 48 h, respectively. CONCLUSION: EMDs enhance the proliferation and ALP activity of PDLCs, and promote the release of growth factors, including VEGF and TGF-β, from PDLCs. Therefore EMDs could be one of the effective methods for periodontal regeneration.

Histomorphometric Evaluation of Onlay Freeze-Dried Block Bone and Deproteinized Bovine Bone with Collagen in Rat

The aim of this study was to evaluate the effect of human freeze-dried bone block (FDBB) and deproteinized bovine bone with collagen (DBBC) on bone formation when applied as an onlay graft in rat calvariums. Thirty male Sprague-Dawley rats received collagen sponge (control), FDBB, or DBBC onlay grafts trimmed into 8-mm disks measuring 4-mm height. Each graft was secured onto the calvarium surface using horizontal mattress sutures. Rats in each group were killed at 2 (n=5) or 8 (n=5) weeks postoperatively for histologic and histomorphometric analysis. The total augmented area (mm²), new bone area (mm²), and bone density (%) were measured. The FDBB and DBBC groups showed significantly more new bone formation and bone density than the control group at 2 and 8 weeks. The increased new bone area was significantly greater in the FDBB group than in the DBBC group (p<0.05). The total augmented area was significantly higher in the FDBB and DBBC groups at 2 and 8 weeks than in the control group (p<0.05), and at 8 weeks, the area was significantly decreased in the DBBC group compared to that in the FDBB group and the area at 2 weeks (p<0.05). Within the limitations of the present study, we concluded that onlay FDBB and DBBC grafts caused new bone formation through an osteoconductive mechanism. In addition, compared to FDBB, DBBC had less capacity to form new bone and maintain the space.

Effects of Block Bone Substitutes Loaded with Escherichia Coli-Produced Recombinant Human Bone Morphogenetic Protein-2 on Space Maintenance and Bone Formation in Rat Calvarial Onlay Model

We aimed to evaluate the effects of onlay-type grafted human freeze-dried corticocancellous bone block (FDBB) and deproteinized bovine bone with collagen (DBBC) loaded with Escherichia coli-produced recombinant human bone morphogenetic protein-2 (ErhBMP-2) on space maintenance and new bone formation in rat calvaria. Collagen sponge (CS), FDBB, or DBBC disks (8×4 mm) with ErhBMP-2 (2.5 µg) were implanted onto the calvaria of male Sprague-Dawley rats, whereas CS with buffer was implanted onto the calvaria as controls (n=20/carrier). Rats were killed at 2 or 8 weeks post-surgery for histologic and histomorphometric analyses; total augmented area, new bone area, and bone density were evaluated. At both time-points, all ErhBMP-2 groups showed significantly higher new bone area and bone density than the control group (p<0.05). ErhBMP-2/FDBB and ErhBMP-2/DBBC groups showed significantly higher total augmented area than ErhBMP-2/CS group (8 weeks), and ErhBMP-2/FDBB group showed significantly higher new bone area and bone density than ErhBMP-2/DBBC group (p<0.05). ErhBMP-2/CS group showed the highest bone density (p<0.05). Combining ErhBMP-2 with FDBB or DBBC could significantly improve onlay graft outcomes, by new bone formation and bone density increase. Moreover, onlay-grafted FDBB and DBBC with ErhBMP-2 could be an alternative to autogenous block onlay bone graft.

A prospective study of patient satisfaction after implant supported mandibular overdenture treatment in fully edentulous patients / 대한치과보철학회지

PURPOSE: The purpose of this prospective study was to compare the satisfaction levels of the patients worn implant supported mandibular overdentures and conventional complete dentures. MATERIALS AND METHODS: Full edentulous patients (n=40) who were planned to do implant supported mandibular overdentures, aged 51 to 82 years, were enrolled in this study. All subjects rated their satisfaction levels (mastication, pronunciation, esthetics, pain, and general satisfaction) of their original conventional dentures prior to treatment and their new overdentures 1 week and 12 weeks after the delivery on 10 cm visual analogue scales. Repeated-measures ANOVA was performed to compare the satisfaction level of each three period (P<.05). RESULTS: The mean satisfaction levels of the implant supported overdentures after 1 week and 12 weeks of delivery were significantly higher than those of the conventional complete dentures in all scoring parameters (P<.05). After 12 weeks of overdenture delivery, the increase of the satisfaction levels in mastication, pronunciation, and pain and the decrease in esthetics and general satisfaction were observed in comparison with those after 1 week of delivery, however, no significant difference was found between the satisfaction levels of 1 week and 12 weeks after delivery. CONCLUSION: An implant supported overdenture might be one of the effective ways to give more satisfaction to patients who were not gratified with a conventional denture and eventually to improve their quality of life.

Effects of adjunctive daily phototherapy on chronic periodontitis: a randomized single-blind controlled trial

PURPOSE: The purpose of this randomized single-blind controlled trial was to elucidate the clinical and antimicrobial effects of daily phototherapy (PT) as an adjunct to scaling and root planing (SRP) in patients with chronic periodontitis. METHODS: The study was conducted from December 2013 to May 2014 at Ewha Womans University Mokdong Hospital, Seoul, Korea. Forty-one patients with mild to moderate chronic periodontitis were randomly divided into two therapeutic groups in a 1:1 ratio: SRP+PT and SRP (control) groups. All participants underwent full-mouth SRP. PT was performed thrice a day for a month by using electric toothbrushes with embedded light-emitting diodes. Plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing were assessed before (baseline) and four weeks after (follow-up) the treatment. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Campylobacter rectus, Eikenella corrodens, Streptococcus mutans, and Streptococcus sobrinus levels were detected by a real-time polymerase chain reaction at the same points in time. RESULTS: The clinical parameters improved in both the groups. At the follow-up assessment, PPD was significantly decreased in the SRP+PT group (P=0.00). Further, PPD and CAL showed significantly greater changes in the SRP+PT group than in the SRP group (PPD, P=0.03; CAL, P=0.04). P. gingivalis and T. forsythia levels decreased in this group, but no significant intergroup differences were noted. CONCLUSIONS: Adjunctive PT seems to have clinical benefits, but evidence of its antimicrobial effects is not sufficient. Long-term studies are necessary to develop the most effective PT protocol and compare the effectiveness of PT with and without exogenous photosensitizers.

Anterior maxillary defect reconstruction with a staged bilateral rotated palatal graft

PURPOSE: In the anterior maxilla, hard and soft tissue augmentations are sometimes required to meet esthetic and functional demands. In such cases, primary soft tissue closure after bone grafting procedures is indispensable for a successful outcome. This report describes a simple method for soft tissue coverage of a guided bone regeneration (GBR) site using the double-rotated palatal subepithelial connective tissue graft (RPSCTG) technique for a maxillary anterior defect. METHODS: We present a 60-year-old man with a defect in the anterior maxilla requiring hard and soft tissue augmentations. The bone graft materials were filled above the alveolar defect and a titanium-reinforced nonresorbable membrane was placed to cover the graft materials. We used the RPSCTG technique to achieve primary soft tissue closure over the graft materials and the barrier membrane. Additional soft tissue augmentation using a contralateral RPSCTG and membrane removal were simultaneously performed 7 weeks after the stage 1 surgery to establish more abundant soft tissue architecture. RESULTS: Flap necrosis occurred after the stage 1 surgery. Signs of infection or suppuration were not observed in the donor or recipient sites after the stage 2 surgery. These procedures enhanced the alveolar ridge volume, increased the amount of keratinized tissue, and improved the esthetic profile for restorative treatment. CONCLUSIONS: The use of RPSCTG could assist the soft tissue closure of the GBR sites because it provides sufficient soft tissue thickness, an ample vascular supply, protection of anatomical structures, and patient comfort. The treatment outcome was acceptable, despite membrane exposure, and the RPSCTG allowed for vitalization and harmonization with the recipient tissue.

The effect of copper alloy scaler tip on the surface roughness of dental implant and restorative materials / 대한치과보철학회지

PURPOSE: This study is designed to investigate the various impacts of different types of scaler tips such as cooper alloy base tip and the others on the surface roughness of teeth and implant by the method which is currently in clinical use. MATERIALS AND METHODS: Four different types of disc shaped porcelain, titanium, zirconia, and Type III gold alloy dental materials sized 15 mm diameter, 1.5 mm thickness were used for the experiment. Plastic hand curette (Group PS), cooper alloy new tip (Group IS), and stainless steel tip (Group SS) were used as testing appliances. A total of 64 specimens were used for this study; Four specimens for each material and appliance group. Surface roughness was formed with 15 degree angle in ultrasonic scaler tip and with 45 degree angle in hand curette of instrument tip and the specimen surface with 5 mm long, one horizontal-reciprocating motion per second for 30 seconds by 40 g force. To survey the surface roughness of each specimen, a field emission scanning electron microscope, an atomic force microscope, and a surface profiler were used. (Ra, microm). RESULTS: According to SEM, most increased surface roughness was observed in SS group while IS groups had minimal roughness change. Measurement by atomic force microscope presented that the surface roughness of SS group was significantly greater than those of PS, IS and control groups in the type III gold alloy group (P<.05). IS group showed lesser surface roughness changes compared to SS group in porcelain and gold alloy group (P<.05). According to surface profiler, surface roughness of SS group showed greater than those of PS, IS and control groups and IS group showed lesser than those of SS group in all specimen groups. Type III gold alloy group had large changes on surface roughness than those of porcelain, titanium, zirconia (P<.05). CONCLUSION: The result of this study showed that newly developed copper alloy scaler tip can cause minimal roughness impacts on the surface of implant and dental materials; therefore this may be a useful alternative for prophylaxis of implant and restored teeth.

Preliminary evaluation of a three-dimensional, customized, and preformed titanium mesh in peri-implant alveolar bone regeneration

OBJECTIVES: The purpose of this preliminary study is to evaluate the effectiveness of a customized, three-dimensional, preformed titanium mesh as a barrier membrane for peri-implant alveolar bone regeneration. MATERIALS AND METHODS: Ten patients were recruited for this study. At the time of implant placement, all patients had fenestration or a dehiscence defect around the implant fixture. A mixture of particulate intraoral autologous bone and freeze-dried bone allograft was applied to the defect in a 1 : 1 volume ratio and covered by the preformed titanium mesh. A core biopsy specimen was taken from the regenerated bone four months postoperatively. Patients were followed for 12 months after the definitive prosthesis was placed. RESULTS: Satisfactory bone regeneration with limited fibrous tissue was detected beneath the preformed titanium mesh. Histologic findings revealed that newly formed bones were well-incorporated into the allografts and connective tissue. New growth was composed of approximately 80% vital bone, 5% fibrous marrow tissue, and 15% remaining allograft. All implants were functional without any significant complications. CONCLUSION: The use of preformed titanium mesh may support bone regeneration by maintaining space for new bone growth through its macro-pores. This preliminary study presents the efficacy of a preformed titanium mesh as a ready-to-use barrier membrane around peri-implant alveolar bone defect. This preformed mesh is also convenient to apply and to remove.

Labial and lingual/palatal bone thickness of maxillary and mandibular anteriors in human cadavers in Koreans

PURPOSE: The aim of this study is to evaluate the buccal and lingual bone thickness in the anterior teeth and the relationship between bone thickness and the tissue biotype. METHODS: Three male and two female human cadaver heads (mean age, 55.4 years) were used in this study. First, the biotype of periodontium was evaluated and categorized into a thick or a thin group. Next, full thickness reflections of the mandible and the maxilla to expose the underlying bone for accurate measurements in the anterior regions were performed. After the removal of the half of the alveolar bone, the probe with a stopper was used to measure the thickness of bone plate at the alveolar crest (AC), 3 mm apical to the alveolar crest (AC-3), 6 mm apical to the alveolar crest (AC-6), and 9 mm apical to the alveolar crest (AC-9). RESULTS: Four of them had a thick biotype. There was no penetration or dehiscence. The thickness of the buccal plates at the alveolar crest were 0.97+/-0.18 mm, 0.78+/-0.21 mm, and 0.95+/-0.35 mm in the maxillary central incisors, lateral incisors, and canines, respectively. The thickness of the labial plates at the alveolar crest were 0.86+/-0.59 mm, 0.88+/-0.70 mm, and 1.17+/-0.70 mm in the mandibular central incisors, lateral incisors and canines, respectively. CONCLUSIONS: The thickness of the labial plate in the maxillary anteriors is very thin that great caution is needed for placing an implant. The present study showed the bone thickness of maxillary and mandibular anteriors at different positions. Therefore, these data can be useful for the understanding of the bone thickness of the anteriors and a successful implant placement.