Esthetic outcome of implant-supported single-tooth replacements assessed by the patient and by prosthodontists

PURPOSE: The objective of this study was to assess and compare patients' and clinicians' judgments of the esthetic outcome of implant-supported single-tooth replacements. MATERIALS AND METHODS: In all, 29 patients with 41 single implant-supported crowns in the maxillary anterior region participated in the study. The esthetic outcome of the implant-supported crowns was assessed by the patients and by 5 prosthodontists by means of a questionnaire in which various esthetics-related variables were addressed and responded to using visual analogue scales. Multiple regression analyses were used to evaluate the influence of the variables on the "overall satisfaction" with the implant-supported crown. RESULTS: Most variables in the patients' assessments revealed mean values above 90% and median values close to 100%. No single factor used in the multiple regression analysis was found to influence a patient's satisfaction with appearance of the crown at a statistically significant level. The clinicians' degree of satisfaction was for all variables lower than that of the patients. In 89% of the cases the clinicians could correctly locate the single implant-supported crown. Among the variables assessed, surrounding soft tissue appearance and form of the crown had the strongest influence on the clinician's overall satisfaction with the appearance of the crown. CONCLUSION: Appreciation of the esthetic outcome of the single implant-supported crowns was rated higher by the patients than by the prosthodontists. Furthermore, factors considered by professionals to be of significance for the esthetic result of the restorative treatment may not be of decisive importance for the patient's satisfaction.     

Reconstruction of the severely resorbed atrophic edentulous ridge of the maxilla and mandible for implant rehabilitation: report of a case

We describe a case with a severely resorbed atrophic edentulous ridge in both the maxilla and mandible. The maxilla was reconstructed using a sinus-lifting procedure and onlay bone graft. The mandible was reconstructed by anterior osteotomy with an interpositional sandwich iliac bone graft at the symphysis area, subperiosteally with iliac bone chips mixed with hydroxylapatite bilaterally at the posterior atrophic ridge, and vestibuloplasty with a split thickness skin graft (STSG). After full-mouth implant rehabilitation, a 5-year follow-up of this case shows a satisfactory result.     

Resin-bonded fixed partial dentures: A recall study

A clinical recall program was initiated at the University of Minnesota to evaluate the longevity and factors affecting longevity of resin-bonded fixed partial dentures (FPDs). Of the 49 resin-bonded FPDs evaluated in the clinic, 43 were acid-etched metal, resin-bonded FPDs, four were combinations of resin-bonded and conventional FPDs, and two were composite resin pontics. None of the combination FPDs and one of the two composite resin pontics were judged as failed at the examination. Of the 43 acid-etched metal resin-bonded FPDs, 15 were found to be debonded (failure rate = 34.9%). The average length of service for the 43 FPDs was 47.3 months. The average time of placement to debondment was 33 months for the 15 debonded FPDs. The failure rate for maxillary FPDs and FPDs with two retainers were significantly lower than the failure rate for mandibular FPDs and FPDs with more than two retainers (p greater than 0.05). The clinical significance of the present study was discussed.     

Removal of intrinsic enamel stains with vital bleaching and modified microabrasion.

This study utilized a vital bleaching agent as well as an enamel microabrasion compound with low hydrochloric acid concentration to remove intrinsic stains on the facial surfaces of anterior teeth. In addition, scanning electron microscopic analyses of enamel from extracted teeth compared the etching pattern of the commercial compound used in this study to 18% hydrochloric acid. Type 1 and Type 2 etch patterns were observed with 18% hydrochloric acid after 5 and 20 seconds, respectively. Milder and more diffuse etch patterns were observed with the enamel microabrasion compound. A conservative form of treatment to remove intrinsic stains would employ the use of a vital bleaching agent, followed by an enamel microabrasion compound.     

Shear bond strengths of plastic brackets with a mechanical base

This study compares the shear bond strengths of plastic brackets with a mechanical base and metal brackets using two different adhesives, and examines the modes of failure using a scanning electron microscope (SEM). Forty extracted human premolars were selected for bonding. Two types of brackets: metal and plastic-Spirit MB, and two orthodontic adhesives: System 1 + and Enlight, were used. After bonding, all samples were put into a 37 degrees C distilled water bath for 24 hours before shear bond strengths were tested. The bond strengths of the plastic brackets were significantly lower than those of the metal brackets (P < .0001). There was a statistically significant difference in bond strengths between System 1 + and Enlight for plastic brackets (P < .05), but not for metal brackets. The modes of failure predominantly occurred at the enamel/adhesive interface in the metal bracket-System 1 + group, within the adhesive in the metal bracket-Enlight and plastic bracket-System 1 + groups, and at the bracket/adhesive interface in the plastic bracket-Enlight group.     

Effects of lipopolysaccharides and prostaglandins on rat bone cell calcium and cyclic AMP.

Bone cells were isolated by collagenase digestion of 19–21 day old fetal rat calvaria. At 37 °C, lipopolysaccharides decreased Ca uptake 30–70 per cent below control values. At 4 °C, 100–900 per cent increases in Ca uptake were observed. Incubation with lipid A produced similar effects. No effects of lipopolysaccharides on cyclic AMP were noted. Prostaglandins E₁, E₂ and A₁ had no effects on calcium transport but produced characteristic increases in cyclic AMP.     

Synergistic effects of verapamil on pingyangmycin-induced cytotoxicity and apoptosis in KB cells

OBJECTIVES: Previous studies have shown that pingyangmycin (PYM; bleomycin A5) can induce two distinct modes of cell death (necrosis, apoptosis). At high concentrations, PYM can be considered as an apoptosis mimetic drug. In this study, we explored the possibility that the membrane-modifying agent verapamil might affect the transport function of PYM through the plasma membrane, resulting in inducing apoptosis of tumor cells at low concentration of PYM. METHODS: Cytotoxicity, flow cytometry and DNA fragmentation assays were used to detect the interaction of verapamil and PYM in human oral carcinoma cell line KB cells. RESULTS: Our results indicated that verapamil can enhance the cytotoxicity of PYM against KB cells with the non-toxic doses (P<0.05). The cell viability at a concentration of 500 microg ml-1 of PYM was 35+/-2% compared with control and 10 microg ml-1 verapamil decreased the cell viability lower to 28+/-1%. In addition, because of the synergistic effect of verapamil, KB cells apoptosis was found to be induced when treated with a lower concentration of PYM (50 microg ml-1) for 24 h by flow cytometry and DNA fragmentation assays. CONCLUSIONS: Verapamil was found to enhance PYM-induced cytotoxicity and apoptosis in KB cells. The responsiveness of PYM might be explained by the effective accumulation of PYM by verapamil in KB cells mediated by the inhibition of PYM efflux function of the cells.     

Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by Porphyromonas endodontalis in human pulp cells

AIM: To investigate the tissue type plasminogen activator (t-PA) activity in human pulp cells stimulated with Porphyromonas endodontalis (P. endodontalis) in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002. METHODOLOGY: The supernatants of P. endodontalis were used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search for possible signal transduction pathways, SB203580, U0126 and LY294002 were added to test how they modulated the t-PA activity. RESULTS: The main casein secreted by human pulp cells migrated at 70 kDa and represented t-PA. Secretion of t-PA was found to be stimulated with P. endodontalis during 2-day cultured period (P < 0.05). From the results of casein zymography and ELISA, SB203580 and U0126 significantly reduced the P. endodontalis stimulated t-PA production respectively (P < 0.05). However, LY294002 lacked the ability to change the P. endodontalis stimulated t-PA production (P > 0.05). CONCLUSIONS: Porphyromonas endodontalis enhances t-PA production in human pulp cells, and the signal transduction pathways p38 and MEK are involved in the inhibition of t-PA.