Effect of different adhesive systems and post surface treatments on the push-out bond strengths of fiber-reinforced post / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the push-out bond strength of glass-fiber post cemented with different adhesive systems and surface treatments. MATERIALS AND METHODS: 160 tooth samples made from 48 human maxillary single-rooted teeth with similar root length were divided into 4 groups according to the adhesive system (no adhesive, Adper Single Bond 2, Clearfil SE Bond, Clearfil S3). Each group had 4 subgroups according to the post surface treatment methods (no treatment, sandblast, silane, sandblast and silane). Posts (Parapost Fiber White) were cemented with Rely X Unicem. The teeth were sectioned perpendicular to their long axis into 1-mm thick sections. The push-out tests was performed at a speed of 0.5 mm/min. The results were evaluated by 2-way ANOVA, 1-way ANOVA and multiple comparison procedures (Tukey test) (α=0.05). RESULTS: Tukey test showed that the adhesive system significantly influenced the push-out strength. The Clearfil SE Bond group showed the highest value. Post surface treatments showed no significant effect. CONCLUSION: Bond strength of glass-fiber post cemented with self-adhesive resin cement using Clearfil SE Bond showed significantly higher values compared to other adhesive systems.

Long-term cumulative survival and mechanical complications of single-tooth Ankylos Implants: focus on the abutment neck fractures

PURPOSE: To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth Ankylos(R) implants. MATERIALS AND METHODS: This was a retrospective clinical study that analyzed 450 single Ankylos(R) implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position. RESULTS: The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05). CONCLUSION: The Ankylos(R) implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.

Comparable efficacy of silk fibroin with the collagen membranes for guided bone regeneration in rat calvarial defects

PURPOSE: Silk fibroin (SF) is a new degradable barrier membrane for guided bone regeneration (GBR) that can reduce the risk of pathogen transmission and the high costs associated with the use of collagen membranes. This study compared the efficacy of SF membranes on GBR with collagen membranes (Bio-Gide(R)) using a rat calvarial defect model. MATERIALS AND METHODS: Thirty-six male Sprague Dawley rats with two 5 mm-sized circular defects in the calvarial bone were prepared (n=72). The study groups were divided into a control group (no membrane) and two experimental groups (SF membrane and Bio-Gide(R)). Each group of 24 samples was subdivided at 2, 4, and 8 weeks after implantation. New bone formation was evaluated using microcomputerized tomography and histological examination. RESULTS: Bone regeneration was observed in the SF and Bio-Gide(R)-treated groups to a greater extent than in the control group (mean volume of new bone was 5.49 +/- 1.48 mm3 at 8 weeks). There were different patterns of bone regeneration between the SF membrane and the Bio-Gide(R) samples. However, the absolute volume of new bone in the SF membrane-treated group was not significantly different from that in the collagen membrane-treated group at 8 weeks (8.75 +/- 0.80 vs. 8.47 +/- 0.75 mm3, respectively, P=.592). CONCLUSION: SF membranes successfully enhanced comparable volumes of bone regeneration in calvarial bone defects compared with collagen membranes. Considering the lower cost and lesser risk of infectious transmission from animal tissue, SF membranes are a viable alternative to collagen membranes for GBR.

Full mouth rehabilitation in a patient with loss of vertical dimension caused by severe tooth loss: a case report / 대한치과보철학회지

Decrease of occlusal vertical dimension (OVD) due to loss of teeth structure and destruction of the occlusal plane by severely worn dentition may cause cross bite or temporomandibular joint disorder by following change of facial feature or the loss of anterior guidance. Full mouth rehabilitation via an increase of the OVD can be considered to avoid this problem and proper evaluation of patient's OVD is essential. An 80 year old male visited for overall prosthodontic treatment, cross bite due to continuous wear and following decrease of the OVD were observed. We analyzed the existing occlusal relationship using the diagnostic cast, the radiographic evaluation and clinical test, and then proper increase of OVD was selected. The new OVD on diagnostic wax up was placed by the temporary restoration. After 3 months of observation period, final restoration with fixed partial dentures and implant overdenture were made. Throughout the follow-up period of 8 months, the aesthetic and functional improvement can be obtained.

A study on the prevalence of dental anomalies in Korean dental-patients / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to investigate the prevalence of dental anomalies in outpatient clinics. METHODS: The subjects of this study were 3,133 patients who visited the clinic between January 2009 and June 2011. The dental records and panoramic films of the patients and detection of supernumerary, missing, and impacted teeth, transposition, and peg lateralis were reviewed. The results were analyzed according to gender and types and locations of dental anomalies. RESULTS: Among the patients, 362 had dental anomalies, with a prevalence rate of 11.55%. Congenital missing teeth (5.71%) ranked first in the categories, and impacted teeth (3.09%) ranked second. The percentage of patients having supernumerary teeth, peg lateralis, and dislocated teeth were 1.79%, 1.66%, and 0.45%, respectively. CONCLUSIONS: Congenital missing teeth and impacted teeth are, respectively, the first and second most common dental anomalies in Korean dental patients.

A Study on the Abrasion Resistance and Surface Roughness of the Dental Stones / 대한치과보철학회지

The purpose of this study was to investigate the abrasion resistance and surface roughness of conventional dental stones and improved dental stones and newly developed dental stones. Materials included in this study were several dental stones and newly developed dental stone; 2 type III, 6 type IV(including newly developed dental stone),1 type V Ten specimens for each material,total ninety specimens were made. Each specimen was subjected to 50 complete cycle abrasion under constant load 0.42N at speed of 6mm per sec.The depth after abrasion test was measured for each specimen. Surface roughness before and after abrasion test was compared.The results were as follows ; 1.The resin containing die materials such as Tuff Rock and Resin Rock had superior abrasion resistance. 2.Type IV,V Surface roughnessdental stone exhibited greater abrasion resistance than Type IIIdental stone. 3.The results of the surface roughness showed similar pattern with the abrasion resistance.