Evaluation of the therapeutic efficiency of mandibular anterior implant-supported fixed bridges with cantilevers / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Dental implant technology has developed rapidly in recent years. However, the use of implant-supported fixed bridges with cantilevers has been controversial. The purpose of this study was to evaluate the clinical results of the mandibular anterior implant-supported fixed bridges with a cantilever. Method Thirty-three patients (15 males, 18 females; mean age, 42.6 years; range 20-54 years) with two missing anterior mandibular teeth had single implant-supported fixed bridges with a cantilever. Clinical examination was recorded and radiographs were taken. The mean duration of follow-up was 30 months (15-44 months).</p><p><b>RESULTS</b>All implants survived. Loosening or fracture of the prosthesis was not observed. All patients were satisfied with the treatment. The mean bone resorption values after 12, 24, and 36 months of implant loading were 0.94, 1.18 and 1.35 mm respectively. The changes of gingival papilla height ranged from 0 to 0.5 mm. There was significant difference between 1-year and 2 or 3 years restoration groups regarding the average gingival height changes (P < 0.05).</p><p><b>CONCLUSION</b>After careful and precise selection of patients, restoration with a single implant-supported fixed bridge with a cantilever can be recommended if two anterior mandibular teeth are missing.</p>

Clinical follow-up of ceramic bridges with auro-galvanoforming primary coping and Ni-Cr pontic for restoration of dentition defects / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Alternatives to the conventional auro-galvanoforming ceramic bridge need to be evaluated in long-term longitudinal studies before being recommended for restoration of dentition defects. This study aimed to evaluate the clinical performance of a ceramic bridge with auro-galvanoforming primary coping and Ni-Cr pontic for restoration of dentition defects.</p><p><b>METHODS</b>In total, 114 ceramic bridges with auro-galvanoforming (primary coping and Ni-Cr pontic) were placed in 112 patients with dentition defects. Among them, 83 bridges in 82 patients were available for follow-up after 7 years. We evaluated marginal integrity, color match, gingival inflammation, fracture of ceramic bridges, and recurrent caries.</p><p><b>RESULTS</b>Marginal integrity of the ceramic bridges was perfect in all patients. Most ceramic bridges maintained their original color. Fracture was found in three bridges; the rest were free of fracture, breakage, and loosening. Recurrent abutment caries were not found. Ceramic bridges with auro-galvanoforming (primary coping and Ni-Cr pontic) produced satisfactory clinical outcomes - equivalent to the conventional porcelain-fused-to-metal restoration. This technique is especially useful for dentition defects of the molar area and is cheaper than restoration with noble metal bridges.</p><p><b>CONCLUSIONS</b>Ceramic bridges with auro-galvanoforming (primary coping and Ni-Cr pontic) performed well for the restoration of dentition defects during this follow-up period. More studies are warranted to further evaluate this technique as an alternative to the conventional porcelain-fused-to-metal restoration.</p>

The 6-year clinical comparison of compound galvano-ceramic bridges with gold alloy and Ni-Cr alloy ceramic bridges / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate and compare effects of compound galvano-ceramic bridges with Ni-Cr alloy ceramic bridges and gold alloy ceramic bridges in clinic.</p><p><b>METHODS</b>A total of 105 bridges were made for 103 patients. Of them, 35 were compound galvano-ceramic bridges, 35 Ni-Cr alloy ceramic bridges, and 35 gold alloy ceramic bridges respectively. The marginal fitness and fracture of ceramic bridges were checked and caries or second caries of all abutments were also examined in clinic at 6 years after cementation.</p><p><b>RESULTS</b>The marginal fitness of compound galvano-ceramic bridges was evaluated as good in 100% of the bridges, which was better than the fitness of gold alloy ceramic bridges (91%) and Ni-Cr alloy ceramic bridges (77%) (P < 0.01). There was no difference in fracture of ceramic layer among compound galvano-ceramic, gold alloy ceramic, and Ni-Cr alloy ceramic bridges at 6 years (P > 0.05). None of compound galvano-ceramic bridge was found out caries or second caries of abutments. Two of 35 (6%) gold alloy ceramic bridges was found out second caries of abutments and five of 35 (14%) Ni-Cr alloy ceramic bridges were found out caries or second caries of abutments at 6 years. None of frameworks of all bridges was loose or broken.</p><p><b>CONCLUSIONS</b>The 6-year clinical study on compound galvano-ceramic bridges presents good results in marginal fitness and fracture resistance, which indicates the compound galvano-ceramic bridge can be used in clinic.</p>

Fatigue cyclic loading test of an auro-galvanoforming ceramic bridge / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In dental clinics, dentition defects are commonly restored with conventional porcelain-fused-to-metal fixed bridges. However, Ni-Cr alloy ceramic fixed bridges are known to have several drawbacks such as marginal coloration of the neck, low casting precision and, most seriously, poor biocompatibility. These problems could be circumvented by using noble metal ceramic bridges; however, one negative issue related to the conventional noble metal ceramic bridges is its high price due to the use of a large amount of gold for pontic. Therefore, an auro-galvanoforming ceramic bridge would be ideal to retain the advantages of a conventional material, yet reduce the amount of noble metal used. This study aimed to investigate whether any destructive changes occur to the auro-galvanoforming ceramic bridge under a fatigue cyclic loading test.</p><p><b>METHODS</b>On standard models which the left maxillary first premolar is lost and with the cuspid teeth and the second premolar as the fixed bridge abutment teeth, six maxillary auro-galvanoforming ceramic bridges and six corresponding nichrome ceramic jointed crowns were made as group A, six nichrome ceramic bridges and six corresponding nichrome ceramic jointed crowns were made as group B (control group). And then all specimens were fixed and tested on a fatigue cyclic loading machine; the changes occurring to the surfaces of occlusal contact with large functional area and to the porcelain-metal interfaces of the nichrome primary copings margins were observed through a scanning electron microscope (SEM).</p><p><b>RESULTS</b>In 120 hours' continual observation, none of the specimens had porcelain coating fractures or scraping occurrence and all of the porcelain coatings had been kept intact under sinusoidal cyclic loading with the load range of 120 - 200 N and frequency of 5 Hz.</p><p><b>CONCLUSIONS</b>Auro-galvanoforming ceramic bridges exhibited excellent fatigue strength in the fatigue cyclic loading test and may satisfy the clinical demand in theory, while the practical application shall be evaluated by observations in long-term clinical usage.</p>

The evaluation of the carbon fiber post system on restoration of teeth defect in children / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Post and post-core systems are used to restore extensively damaged teeth. Among these systems, cast alloy post and core, prefabricated threaded alloy post and prefabricated simple alloy post are most frequently applied in China nowadays. In Europe and North America a combined application of the fiber post, resin-core and crown has been applied to restore seriously destructed teeth with satisfactory results in recent years. This study was intended to evaluate the clinical effect of carbon fiber post system on restoration of child anterior tooth defect after root canal therapy, based on 3 - 5 years' observation.</p><p><b>METHODS</b>One hundred and six children with incompletely established occlusion were observed and followed for an average of 42 months (ranging from 36 to 60 months). Eighty-five upper teeth and forty-one lower teeth were restored with carbon fiber post system and composite jacket crown. Periodic check-up was conducted for periodontal condition and restoration effect.</p><p><b>RESULTS</b>One hundred and twenty-one (96.2%) restorations were successful. Four jacket crowns (3.0%) were lost. One tooth (0.8%) had slight gingival inflammation. Tooth root or post fracture and gingival stain were not observed. X-ray showed there was no obvious change in aspects including the width of periodontal membrane, the density of alveolar bone and the height of alveolar ridge crest.</p><p><b>CONCLUSIONS</b>Carbon-fiber post system can satisfy the clinical requirements of young patients who have residual anterior crown and root caused by trauma or caries, and have incomplete occlusion and have completed root canal therapy. This system helps realize good esthetic result for patients and easy practice for dentists. Carbon fiber post is safe and convenient, especially for sick children.</p>

The measurement and comparison of shear fracture strength and shear bond strength between carbon fiber post and some other posts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>The shear fracture strengths of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin and the shear bonding strengths of the first three kinds of post bonded in the human root canals were measured and compared, which are as the reference for dental clinic.</p><p><b>METHODS</b>Standard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post, cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin, three for each group. The shear fracture strengths of these samples were measured by universal testing machine (AUTOGRAPH DCS5000). Standard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, five for each group. They were bonded in extracted human root canals that had been prepared to 3.0 mm length and 2.0 mm diameter with Glass ionomer cement (Japan Shofu). The shear bond strengths were measured by the same universal testing machine.</p><p><b>RESULTS</b>The shear fracture strengths of the carbon fiber post (199MPa), cast Ni-Cr alloy post (210MPa, shear bend strength) and prefabricated zirconia ceramic post (193MPa) were statistically higher than those of IPS-Empress 2 all-ceramic post (109MPa) and human dentin (100MPa). The shear fracture strength of the carbon fiber post was statistically similar to that of cast Ni-Cr alloy post and prefabricated zirconia ceramic post. There were no statistical differences between the shear bond strengths of carbon fiber post (2.4MPa) and cast Ni-Cr alloy post (3.8MPa). IPS-Empress 2 all-ceramic post broke before debonding (2.7, break value).</p><p><b>CONCLUSIONS</b>Carbon fiber post, as well as cast Ni-Cr alloy post and prefabricated zirconia ceramic post, has a comparatively high shear fracture strength. The shear bond strengths of carbon fiber post is similar to cast Ni-Cr alloy post.</p>