An increasing number of implant restoration abutment types are produced with the rapid development of dental implantology. Although various abutments can meet different clinical demands, the selection of the appropriate abutment is both difficult and confusing. This article aims to help clinicians select the appropriate abutment by describing abutment design, types, and selection criteria.
Dental Abutments ; Dental Implant-Abutment Design ; Dental Implants ; Humans ; Tooth

OBJECTIVETo evaluate the abutment periodontium condition after restored with the distal-extension extracoronal attachment dentures.

METHODS20 mandibular distal-extension cases were followed up, to measure the gingival index (GI) and plaque index (PLI) of the distant-abutments before restored with attachment dentures and after restored for one month, six months and one year; to compare the length of distant alveolar bone before restored with that after restored one year by taking digital stomatology tomogram photos.

RESULTSThere were not significantly different in the PLI of distant-abutment between before repaired and after repaired one month, six months, one year (P > 0.05). There were not significantly different in the GI of distant-abutment between before repaired and after repaired one month, six months (P > 0.05), but the GI of distant-abutment after repaired one year was significantly higher than that before repaired (P < 0.05). There were no significant differences on the length of distant alveolar bone in distant-abutment before repaired and after repaired one year(P > 0.05).

CONCLUSIONIt is important to protect the periodontal health of the abutment when restored with distal-extension extracoronal attachment dentures. It is necessary to examine periodically after restored in order to keep the periodontal health of the abutment.

PURPOSE: The purpose of present study is to examine the correlation between the accuracy of abutment preparation and the marginal adaptation of metal coping. With this view, this study compared the correlations regard to the three different manufacturing methods of selective laser sintering technique, milling and casting. MATERIALS AND METHODS: Two master models were made in a different way. First model with deep chamfer margin was prepared directly by a general clinician and the second model was designed by 3-D designing software program with the same abutment preparation principle and produced by computer aided manufacturing. 12 Co-Cr alloy copings were produced respectively with three different method; SLS system, CAD/CAM milling and conventional lost wax technique from each master model. The total 72 copings fully sit on the master model were stereoscopically evaluated at 40 points along the entire circumferential margin. RESULTS: Significant differences in the absolute marginal discrepancies of Co-Cr copings from SLS system (P=.0231) and casting method (P<.0001) were shown between hand preparation model and computer designed model. However, no significant difference was found between the two model groups from milling method (P=.9962). CONCLUSION: Within the limitation of this study, the effect of the accuracy of abutment preparation on the marginal adaptation of Co-Cr coping is statistically significant in SLS system and casting group. The copings produced by SLS system exhibited the lowest marginal discrepancies among all groups, and the marginal gap of this method group was influenced by the accuracy of the abutment preparation.
Alloys* ; Computer-Aided Design ; Dental Abutments ; Hand ; Tooth Preparation* ; Tooth*

PURPOSE: The aim of this in vitro study is to investigate load bearing capacity of esthetic abutments according to the type of material and wall thickness. MATERIALS AND METHODS: 70 specimens equally divided into seven groups according to their abutment wall thicknesses. The abutments prepared with titanium 0.5 mm wall thickness were used as a control group (Ti-0.5), whereas zirconia abutments and resin nano ceramic abutments with wall thickness 0.5 mm, 0.8 mm and 1.0 mm were prepared as test groups (Zir-0.5, Zir-0.8, Zir-1.0 and RNC-0.5, RNC-0.8, RNC-1.0). All specimens were tested in a universal testing machine to evaluate their resistance to fracture and all of them underwent thermo-cycling before loading test. Mean fracture values of the groups were measured and statistical analyses were made using two-way ANOVA. RESULTS: Zir-1.0 showed the highest mean strength (2,476.3 ± 342.0 N) and Zir-0.8 (1,518 ± 347.9 N), Ti-0.5 (1,041.8 ± 237.2 N), Zir-0.5 (631.4 ± 149.0 N) were followed. The strengths of RNC groups were significantly lower compared to other two materials (RNC-1.0 427.5 ± 72.1, RNC-0.8 297.9 ± 41.2) and the strengths of all the test groups decreased as the thickness decreases (P < .01). RNC-0.5 (127.4 ± 35.3 N) abutments were weaker than all other groups (P < .05). CONCLUSION: All tested zirconia abutments have the potential to withstand the physiologic occlusal forces in anterior and posterior regions. In resin nano ceramic abutments, wall thickness more than 0.8 mm showed the possibility of withstanding the occlusal forces in anterior region.
Bite Force ; Ceramics* ; Dental Abutments ; In Vitro Techniques ; Titanium ; Weight-Bearing

OBJECTIVE: To observe the effects of a modified semi-fixed bridge to restore a missing posterior tooth for three years. METHODS: In the study, 38 cases with a posterior tooth missed were chosen as experiment group. The inclusion criteria for these cases required that one abutment tooth be defected, and another abutment intact. The missed posterior tooth was restored with a modified semi-fixed bridge in which a metal wing retainer was applied to the intact abutment tooth and a full crown retainer was applied to the defected abutment tooth, and the non-rigid connector linked to the metal wing retainer and the pontic, while the rigid connector linked to the full crown retainer and the pontic. And 42 cases with same abutment conditions were chosen as control group. These control patients were treated with classical rigidly-fixed partial dentures. The clinical effects regarding the bridge survival, abutment conditions, and etc. were observed by examination. RESULTS: The average observation time for experiment group was 40.3 months (from 9 to 60 months). One case failed with loose crown retainer after 7 months' usage. Another failed case was the same performance after 20 months' wearing. The restorations were rebounded after the inner face of crowns was treated, and they were used normally. No loose abutment and retainer, no decayed abutment teeth were found, and the marginal adaptations between retainers and abutment teeth were good. The average observation time of control group was 44.7 months(from 22 to 50 months). No secondary decays and loose abutment teeth were detected and the marginal adaptation of the retainers was good. CONCLUSION This modified semi-fixed bridge has similar survival rate and clinical effects to restore a missing posterior tooth when compared with the traditional rigidly-fixed partial dentures. But the long-term observation is required.
Crowns ; Dental Abutments ; Denture, Partial, Fixed ; Humans ; Tooth Loss

This study aims to apply a new expert system to design removable partial denture (RPD) framework. The RPD design is completed in three steps, namely, "selecting missing teeth", "selecting abutment condition", and "selecting personalized clasp". The system can help auxiliary dentists develop personalized treatment plans to reduce their clinical workload. It can also generate a dental preparation guideline for clinical preparation, which can prevent tooth preparation mistakes. By generating the standard electronic drawings of the framework design, the system can reduce the inconvenience caused by manual drawing, thereby facilitating dentist-technician communication and reducing the rate of remade.
Dental Abutments ; Denture Design ; Denture, Partial, Removable ; Expert Systems ; Tooth

PURPOSE: The anterior region is a challenge for most clinicians to achieve optimal esthetics with dental implants. The provisional crown is a key factor in the success of obtaining pink esthetics around restorations with single implants, by soft tissue and inter-proximal papilla shaping. Provisional abutments bring additional costs and make the treatment more expensive. Since one of the aims of the clinician is to reduce costs and find more economic ways to raise patient satisfaction, this paper describes a practical method for chair-side fabrication of non-occlusal loaded provisional crowns used by the authors for several years successfully. METHODS: Twenty two patients (9 males, 13 females; mean age, 36,72 years) with one missing anterior tooth were treated by using the presented method. Metal definitive abutments instead of provisional abutments were used and provisional crowns were fabricated on the definitive abutments for all of the patients. The marginal fit was finished on a laboratory analogue and temporarily cemented to the abutments. The marginal adaptation of the crowns was evaluated radiographically. RESULTS: The patients were all satisfied with the final appearance and no complications occurred until the implants were loaded with permanent restorations. CONCLUSIONS: The use of the definitive abutments for provisional crowns instead of provisional abutments reduces the costs and the same results can be obtained.
Crowns ; Dental Abutments ; Dental Implants ; Dental Marginal Adaptation ; Dental Prosthesis ; Esthetics ; Humans ; Male ; Patient Satisfaction ; Tooth

OBJECTIVEThe purpose of this study was to investigate the clinical effective of immediate restoration with Osstem MS mini-implant in the edentulous space of 5-6 mm.

METHODSThe sample consisted of 36 consecutively treated partially edentulous patients who had a total of 36 Osstem MS mini-implants, which were 2.5 mm or 3.0 mm in diameter and placed in 5-6 mm gap. The chair-side-made or laboratory-made provisional crowns for implants were fabricated at the time of fixtures placed. The final restorations were fabricated with gold alloy-fused-porcelain crown 3 to 5 months later. During the mean 21.3 months (12-37 months) follow-up time since fixtures placement, all implants were examined clinically and radiologically.

RESULTSNo implant failed before restoration. One implant led an adjacent tooth pulp necrosis after the implantation, but the natural tooth and implant were successfully retained by root canal therapy. 36 implants in 36 patients who were followed-up were successful and their aesthetic results were satisfactory.

CONCLUSIONImmediate loaded implant with Osstem MS mini-implant has good clinical prosthetic effects in the edentulous space of 5-6 mm.

UNLABELLEDOBJECTIVE To evaluate the aesthetic effect of restorations with custom pressable metal ceramic abutments for defective soft and hard tissue in the maxillary anterior zone.

METHODSFifty-two patients with missing anterior teeth in the maxillar were selected, who had problems such as exposure of abutment metal, excessively large angle deviation, excessively long ceramic crown and missing gingival papilla, affecting the aesthetic effect of implant denture. Custom pressable metal ceramic abutments were made on the conventional castable metal abutment surface and restored with all-ceramic crowns to overcome the blackness at the implant neck.

RESULTSClinical evaluation for aesthetic effects 3 and 6 months after the restorations were placed. In 63 restorations of 52 patients, the blackness at the implant neck were eliminated and the aesthetic effect were ideal. The gingival was in healthy condition, showing no further gingival retreat or inflammation around the implant denture.

CONCLUSIONCustom pressable metal ceramic abutments can effectively improve the aesthetic appearance of the implant denture in maxillary anterior zone.

The method of modeling and mesh generation about 3-unit tooth/restoration complex were established. The three-dimensional finite element models were subjected to four types of occlusal load applied to pontic element to evaluate 3 fiber framework designs and 3 cavities preparation configurations. By comparing the difference of stress distribution, following conclusions were obtained: the principal stress under buccal-lingual cusp load in traditional fiber framework pontic increased by 6.22% compared to that in pure composite resin pontic; optimized fiber framework obviously reduced stress level under any load; modified cavities exhibited better stress transfer and decreased share stress at adhesive interface than traditional cavities.
Composite Resins ; Dental Abutments ; Dental Materials ; Dental Stress Analysis ; Finite Element Analysis ; Glass ; Models, Theoretical