Esthetic replacement of a maxillary central incisor with an ITI 15-degree angled implant: a case report

Single-stage implants are frequently used, but their use in the anterior dentition has not been widely published. The purpose of this case report is to present the esthetic result of a single-stage implant to replace a maxillary central incisor, and to demonstrate the unconventional use of a 15-degree angled ITI implant. A 15-degree 12-mm hollow cylinder was placed with the angle reversed facially. The emergence profile of the adjacent roots was matched with the transmucosal portion, turning at the osseous crest. The implant was restored after 6 months with an ITI gold coping and transverse screw-retained crown. The gingival margin and the papillae were shaped by the transmucosal portion and the restoration. To date, the implant has been loaded for 24 months with an ideal soft tissue esthetic and radiographic appearance.     

Effect of presilanization filler decontamination on aesthetics and degradation resistance of resin composites

Filler-matrix coupling determines, to a large extent, the mechanical strength and clinical longevity of dental composites. The aim of this study was to examine how far a methodology to decontaminate filler prior to silanization may improve aesthetic performance in addition to physico-mechanical properties such as degradation resistance. It was reported that filler particles are surrounded and wrapped by a film that consists of multiple layers of silane molecules. X-ray photoelectron spectroscopy, however, revealed that silanization of filler particles largely depended upon siloxane bridge (Si-O-Si) formation between the silica surface and the silane molecule rather than on intermolecular bonding between adjacent silane molecules. In this study, we showed that filler decontamination resulted in a higher translucency, thereby providing a better aesthetic potential. In addition, experimental composites produced following presilanization decontamination of filler revealed a higher Vickers hardness value and a diametral tensile strength that was resistant to degradation by thermo-cycling.     

Effects of TGF-beta on hyaluronan anabolism in fibroblasts derived from the synovial membrane of the rabbit temporomandibular joint

Hyaluronan (HA) synthesis in the synovial membrane is affected by various chemical mediators. It is hypothesized that transforming growth factor-beta 1 (TGF-beta 1) would be a mediator to modulate HA synthesis in cultured synovial membrane fibroblasts of the temporomandibular joint (TMJ). Fibroblasts were extracted from the TMJ synovial membrane of four-week-old Japanese white rabbits. The amount of HA and expression levels of HA synthase (HAS) mRNAs induced by TGF-beta 1 treatment were analyzed by means of high-performance liquid chromatography and real-time polymerase chain-reaction, respectively. Both medium and large amounts of HA were enhanced by the stimulation of TGF-beta 1. HAS2 mRNA expression was enhanced 13-fold after six-hour stimulation with TGF-beta 1 (10 ng/mL), whereas HAS3 mRNA expression was not changed significantly. These results suggest that TGF-beta 1 enhances the expression of HAS2 mRNA in the TMJ synovial membrane fibroblasts and may contribute to the production of high-molecular-weight HA in the joint fluid.     

Characterization of mineral-binding 40-kDa glycoprotein extracted from young adult rabbit alveolar bone.

A forty-kilodalton (40-kDa) protein was extracted from alveolar bone of young adult rabbit with 0.5 M EDTA after extraction with 4 M GuHCl, and purified by gel-filtration, anion-exchange and hydroxyapatite columns using a high-pressure liquid chromatography system under denaturing conditions. The purified 40-kDa protein was not susceptible to bacterial collagenase and thrombin, but was cleaved by cyanogen bromide. The protein was stained blue with Stains-all. Among various lectins, concanavalin A and lentil lectin agglutinin bound to this protein, but peanut agglutinin, Ricinus communis agglutinin, phytohemagglutinin-E and wheatgerm lectin agglutinin did not. Lectin binding assays showed that the protein is a glycoprotein containing large amounts of mannose and/or glucose residues, but is not a fragment of proteoglycan. The amino acid composition of the protein shows a characteristically high content of acidic amino acids. Therefore, the mineral-binding 40-kDa glycoprotein is considered to be osteonectin/secreted protein acidic and rich in cysteine (SPARC), in terms of similarities to bovine and porcine osteonectins with regard to molecular weight and contents of glycoses and amino acids.     

Prevalence of Porphyromonas gingivalis in relation to periodontal status assessed by real‐time PCR

Many studies have examined the presence of Porphyromonas gingivalis in periodontal pockets. However, monitoring the number of bacterial cells is difficult. In this study, we performed quantitative analyses of P. gingivalis to clarify the relationship between the numbers of this organism and periodontal status. Using the TaqMan real‐time PCR system, we found a significant positive correlation (P < 0.0001) between the number of P. gingivalis and pocket depth. The slope of the regression line indicated that for every 1‐mm increase in pocket depth, the number of P. gingivalis increased 10‐ fold. There was also a significant reduction (P < 0.01) in the numbers of P. gingivalis before and after treatment. These results suggest that the absolute and relative numbers of P. gingivalis are closely associated with periodontal status, and that quantitative analysis of this organism is important for the evaluation of periodontal therapy.     

Clinical and histological evaluation of immediate-loaded posterior implants in nonhuman primates

PURPOSE: To evaluate a square-thread design implant and compare the bone-implant contact percentage between immediate-loaded and nonloaded implants (controls) in nonhuman primates. MATERIALS: Five nonhuman primates each received 3 implants, with a total of 5 control implants and 10 immediate-loaded implants in posterior regions of the mouth. Ninety days after surgery (and function was appropriate), block sections of the implants were removed and sectioned in 200-mum thick pieces. The block sections were stained with modified Masson for evaluation of the bone-implant contact percentage. RESULTS: One of the immediate-loaded implants failed. The bone-implant contact percentage of control implants ranged from 50.34% to 64.13% and averaged 56.3%. The bone-implant contact percentage of immediate-loaded implants ranged from 43.23% to 75.72%, with an average of 62.4%. Two implants had lower bone-implant contact percentage than the others, and when these are not included in the evaluation, the bone-implant contact percentage average increased to 67.6%. CONCLUSIONS: Immediate-loaded implants in the nonhuman primates often have a higher bone-implant contact percentage at 90 days than unloaded implants. The bone remodeling is different for loaded implant-bone interfaces than for unloaded conditions. However, 1 immediate-loaded implant failed, and 2 implants had lower bone-implant contact percentage than controls. Therefore, although there are benefits of immediate loading, there appear to also be some risks.     

Temporomandibular joint and masticatory muscle involvement in myotonic dystrophy: a study by magnetic resonance imaging

OBJECTIVE: The purpose of this study was to evaluate the masticatory muscles and the temporomandibular joint (TMJ) by magnetic resonance imaging (MRI) in myotonic dystrophy (MD) patients. STUDY DESIGN: MRI of the masticatory muscles and TMJ was performed in 15 MD patients, 11 male and 4 female, aged 16 to 53 years (mean, 31 years). Many of them had dental malocclusion, especially Angle class III and anterior open bite, and 3 complained of recurrent TMJ dislocation. TMJ and masticatory muscle pain was not observed, and joint sounds were noted in only 1 patient. RESULTS: The analysis of MRI scans showed masticatory muscle involvement in 13 patients (86.6%). In 11, the involvement was moderate to intense. The main abnormalities observed were increased intramuscular tissue signal on T1 (fatty infiltration) and volumetric reduction of muscles. Regarding the TMJ, articular disk displacement was seen in only 1 patient, but abnormalities of disk shape were common. Mild bone abnormalities were frequently observed, including changes of shape and contour of bone surface, and sclerosis of bone marrow. In 4 patients the condyle moved anterior to the eminence with the mouth opened fully (condylar hyperexcursion). CONCLUSIONS: This study shows that masticatory muscles are frequently and intensively affected in MD patients. Bone changes are the most consistent abnormalities observed in the TMJ. It is possible that remodeling is caused by biomechanical changes in the jaw as a result of masticatory muscle involvement.     

Correlation of the near-infrared spectroscopy signals with signal intensity in T(2)-weighted magnetic resonance imaging of the human masseter muscle

The purpose of this study was to compare and contrast blood volume changes transcutaneously measured using near-infrared (NIR) spectroscopy against water signal intensity changes taken from a transverse T(2)-weighted MR image of the masseter muscle in healthy human subjects before, during and after contraction. Eight healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated (mean age: 23.9+/-0.6 years). The MRI data were gathered using a turbo spin echo sequence (TR: 2300 ms; TE: 90 ms; FOV: 188x300 mm; scanning time: 30 s; slice thickness: 10 mm) and the slice level was set at the mid-point between the origin and insertion of the masseter. Intramuscular haemoglobin (Hb) levels and water content of the right masseter muscle were continuously monitored for 2 min before, 30 s during and 15 min after a maximum voluntary clenching (MVC) task. Both the near-infrared and MRI data were baseline-corrected and normalized and mean levels were established and plotted. Plots of the data showed that both near-infrared-based total Hb and T(2)-weighted MRI-based signal-intensity levels clearly decreased during contraction and a clear post-contraction rebound response was evident after the contraction. The near-infrared data were found to be highly correlated with MRI-based signal-intensity data (Pearson's r=0.909, P<0.0001). In conclusion, these data provide powerful evidence that near-infrared data (total Hb), transcutaneously taken from the masseter muscle in humans, will reflect the intramuscular water signal intensity changes seen using a T(2)-weighted MRI imaging method.