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At least 109 records · Page 6Linked to original sources
PubMed2005

Indications for splinting implant restorations.

PURPOSE: The purpose of this article was to review the literature concerning the need to splint implants together when restoring them with a provisional restoration immediately after implant placement. METHODS: The literature is reviewed concerning the rationale for splinting teeth and reports concerning the efficacy of splinting implants together. Based on this team's experience with a prospective series of consecutive 2 to 5 unit provisionalization cases, guidelines are included with case examples for understanding the technique. CONCLUSION: As long as canine guidance is present, and occlusion is stable, multiunit single quadrant restorations do not need to be splinted when provisionalized.

Dental Abutments↗
PubMed2005

Immediate fixed restoration of the edentulous maxilla after implant placement.

Immediate loading of the edentulous maxilla is possible when sufficient bone is available to provide primary stability of implants located in positions congruent with an ideal prosthesis. Treatment planning, implant placement with immediate provisionalization, and final prosthodontic rehabilitation are best integrated by a process that uses the immediate provisional prosthesis as a surgical and restorative guide. Designating the planned tooth position is a prerequisite step to the identification of possible implant positions. The cervical contours of the planned prosthesis are critical determinants of this relationship. Defining the planned tooth/residual alveolar bone relationship aids in selecting both the possible type of prosthesis and implant locations. When the treatment plan is transferred directly from the tomographic template to the surgical template to the conversion prosthesis used for immediate loading, the surgical and prosthodontic management of this procedure is well defined.

Dental Implantation, Endosseous↗
PubMed2005

Prosthodontic considerations for predictable single-implant esthetics in the anterior maxilla.

Long-term functional and esthetic success with implant-supported single-tooth restorations requires a comprehensive and interdisciplinary treatment approach. Important parameters include the initial clinical situation, the surgical approach, the provisional phase, and the choice of abutment material and design as well as the definitive restoration. This article presents the main aspects of current treatment protocols and discusses material options and clinical techniques to achieve predictable outcomes.

Adult↗
PubMed2006

Biomechanical study of a prosthetic solution based on an angled abutment: case of upper lateral incisor.

OBJECTIVES: To study the complex behaviour of an upper lateral incisor restoration using an angled abutment, a mechanical analysis of the abutment bearing capacity was firstly carried out. The evolution of bone properties around implant was then simulated as a function of time to estimate the maximal load that could be supported by the prosthetic solution without bone damage. MATERIALS AND METHODS: According to the Food and Drug Administration procedure, experimental tests were firstly carried out on five samples. A 25 degrees -angled abutment screwed to an implant embedded into a massive steel bloc was submitted to a static loading. Two finite element models were also built: the first one (I) to interpret and complete the results obtained in the experimental part and the second one (II) to simulate bone remodelling around implant considering a strain energy stimulus. RESULTS: According to experiments, the abutment straightening was observed for an average force of 869N. Numerical model (I) confirmed this result and indicated that the initial irreversible deformation (yielding) of abutment was obtained for a 283N compressive force. It could thus be deduced that this abutment can safely be used for an incisor restoration. Model (II) showed that, after 26 months, some of the cancellous bone initially present in an approximately one millimetre thick shell surrounding the implant had reached the density of cortical bone. A safe load notion corresponding to the force leading to the maximal admissible strain value for trabecular bone was introduced. It evolved from 44N after surgery to approximately 160N after 26 months.

Biomechanical Phenomena↗
PubMed2003

Single implant-supported molar and premolar crowns: a ten-year retrospective clinical report.

Evidence of the successful use of osseointegrated dental implants for the restoration of individual teeth has been reported for anterior teeth more frequently than for posterior teeth. Contiguous implants placed in posterior quadrants are often splinted without clear rationale. This clinical report describes the data collected from the charts of patients provided with implant-supported single crowns in posterior quadrants in a prosthodontic practice in southern California. Forty-nine patients with 126 implants restored with molar or premolar crowns were recalled for examination after periods ranging from 6 months to 10 years. The implant failure rate was 4.6%, with complications of abutment screw loosening (7%) and loss of cement bond (22%). Osseointegrated implants in molar and premolar positions may be restored as single crowns.

Adult↗
PubMed2004

Immediate loading of hydroxyapatite-coated implants in the maxillary premolar area: three-year results of a pilot study.

STATEMENT OF THE PROBLEM: Although immediate loading of implants in the edentulous mandible has been described in the literature, there is limited information regarding immediate loading of single implants. PURPOSE: This prospective clinical study evaluated the clinical parameters of immediately loaded single-threaded hydroxyapatite-coated (HA) root form implants. MATERIAL AND METHODS: Ten human subjects were included in this report. In all situations, a screw-retained provisional acrylic resin crown was placed in the maxillary premolar area immediately after implant surgery. Definitive screw-retained metal-ceramic prostheses were placed 6 months after surgery. Standardized periapical radiographs were made before implant surgery, immediately after surgery, and 1, 3, 6, 12, and 36 months after implant surgery. Mobility (measured with the Perio-Test), distance from implant platform to the gingival crevice, distance from the implant platform to the depth of the sulcus, peri-implant probing depth, and bleeding on probing index were recorded at 3, 6, 12, and 36 months after implant placement. For clinical measurements, a 5-mm healing abutment was placed. RESULTS: All implants appeared clinically osseointegrated. Standardized radiographs demonstrated mean marginal bone loss of 0.6, 0.7, 0.8, 0.9, and 1.0 mm at 1, 3, 6, 12, and 36 months after implant surgery, respectively. Mean implant mobility was -3.3 at the day of surgery and -3.8, -3.4, -3.6, and -4.2 at 3, 6, 12, and 36 months, respectively. The distance from implant platform to the gingival crevice was 2.8, 2.4, 2.4, and 3.1 mm at 3, 6, 12, and 36 months, respectively. The distance from the implant platform to the depth of the sulcus was 0.8, 0.9, 0.9, and 1.1 mm at 3, 6, 12, and 36 months, respectively. The peri-implant probing depth was 3.6, 3.3, 3.2, and 4.3 mm at 3, 6, 12, and 36 months, respectively. The bleeding on probing index was 0.4, 0.4, 0.4, and 0.1 at 3, 6, 12, and 36 months, respectively. CONCLUSION: The results of this prospective pilot study provide initial evidence that single root form implants may be immediately loaded when placed at the maxillary premolar area.

Adult↗
PubMed2004

Effect of lateral cyclic loading on abutment screw loosening of an external hexagon implant system.

STATEMENT OF PROBLEM: Efforts to reduce the recurrence of abutment screw loosening with single tooth implant-supported restorations have been reported. However, the current knowledge about the role of the implant external hexagon is incomplete. PURPOSE: This in vitro study investigated the effect of lateral cyclic loading with different load positions on abutment screw loosening of an external hexagon implant system. MATERIAL AND METHODS: Fifteen Brånemark implant assemblies were divided equally into 3 groups, A, B, and C. Each assembly consisted of a Mark IV implant (4 x 10 mm) mounted in a brass block, a CeraOne abutment (3 mm), and an experimental cement-retained superstructure. For group A, a cyclic load of 50 N was applied centrally and perpendicular to the long axis of the implant, whereas for group B, the same load was applied eccentrically (at a distance of 4 mm) in a loosening direction. A target of 1.0 x 10(6) cycles (40 months of simulated function) was defined. Group C (control) was left unloaded for the same loading time period as groups A and B. Reverse torque was recorded before and after loading and the difference was calculated. The data were analyzed with 1-way analysis of variance and compared with the Tukey test (alpha=.05). RESULTS: Group A exhibited a significant difference in the reverse torque difference values ([-5.6 to -3.4] +/- 0.86 N.cm) compared with groups B ([-1.9 to 0.5] +/- 0.99 N.cm) and C ([-0.7 to 0.0] +/- 0.26 N.cm) (P<.001). Groups B and C were not significantly different from each other. CONCLUSION: Within the limitations of this study, reverse torque values of the screw joint were preserved under eccentric lateral loading, as compared with centric loading (P<.001).

Analysis of Variance↗
PubMed2004

Influence of occlusal forces on stress distribution in preloaded dental implant screws.

STATEMENT OF PROBLEM: Abutment and prosthetic loosening of single and multiple screw-retained, implant-supported fixed partial dentures is a concern. PURPOSE: The purpose of this study was to investigate stress distribution of preloaded dental implant screws in 3 implant-to-abutment joint systems under simulated occlusal forces. MATERIAL AND METHODS: Three abutment-to-implant joint systems were simulated by using the 3-dimensional finite element analysis method: (1) Branemark external hexagonal screw-retained abutment, (2) ITI 8-degree Morse tapered cemented abutment, and (3) ITI 8-degree Morse tapered plus internal octagonal screw-retained abutment. A thermal load and contact analysis method were used to simulate the preload resulting from the manufacturers' recommended torques in implant screw joint assemblies. The simulated preloaded implants were then loaded with 3 simulated static occlusal loads (10 N; horizontal, 35 N; vertical, 70 N; oblique) on the crown position onto the implant complex. RESULTS: Numeric and graphical results demonstrated that the stresses increased in both the abutment and prosthetic screws in the finite element models after simulated horizontal loading. However, when vertical and oblique static loads were applied, stresses decreased in the external hexagonal and internal octagonal plus 8-degree Morse tapered abutment and prosthetic screws with the exception of the prosthetic screw of ITI abutment after 70-N oblique loading. Stresses increased in the ITI 8-degree Morse tapered cemented abutment after both vertical and oblique loads. CONCLUSION: Although an increase or decrease was demonstrated for the maximum calculated stress values in preloaded screws after occlusal loads, these maximum stress values were well below the yield stress of both abutment and prosthetic screws of 2 implant systems tested. The results imply that the 3 implant-to-abutment joint systems tested may not fail under the simulated occlusal forces.

Bite Force↗
PubMed2004

A comparison of the porcelain fracture resistance of screw-retained and cement-retained implant-supported metal-ceramic crowns.

STATEMENT OF PROBLEM: The presence of a screw opening on the occlusal surface of implant-supported metal-ceramic crowns may decrease the porcelain fracture resistance and shorten the longevity of the crown. PURPOSE: The purpose of this study was to compare the porcelain fracture resistance between screw-retained and cement-retained implant-supported metal-ceramic crowns and to assess whether narrowing the occlusal table or offsetting the screw-access opening affects fracture resistance. MATERIAL AND METHODS: Forty standardized maxillary premolar metal copings were fabricated with a Pd-Ga alloy (Protocol) on an implant abutment. Copings were divided into 4 groups (n=10): Group 1 (Screw-retained; occlusal surface buccolingual width=5 mm), screw access opening placed in the center of the occlusal surface; Group 2 (Screw-retained; occlusal surface buccolingual width=5 mm), screw access opening positioned 1 mm offset from the center of the occlusal surface toward the buccal cusp; Group 3 (Cement-retained; occlusal surface buccolingual width=5 mm), copings were not altered; and Group 4 (Cement-retained; occlusal surface buccolingual width=4 mm), copings designed to have a reduced occlusal surface width. All castings were finished with aluminum oxide stones and airborne-particle abraded. Two layers of opaque and dentin porcelain were applied, respectively, on all specimens, which were then glazed. The crown specimens were positioned in a custom testing apparatus and vertically loaded on the middle of the occlusal surface with a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Mean values of load at fracture (Kgf) were calculated in each group and compared with a 1-way analysis of variance and Tukey's Studentized test (alpha=.05). RESULTS: Mean values of loads required to fracture the crowns were as follow: Group 1: 95.01+/-46.6 Kgf; Group 2: 108.61+/-57.9 Kgf; Group 3: 390.94+/-151.3 Kgf; Group 4: 380.04+/-211.8 Kgf. Groups 1 and 2 required a significantly lower force to fracture the crowns compared with Groups 3 and 4 (P=.0001). Comparing Group 1 with 2 (P=.9) and Groups 3 with 4 (P=.6), no significant differences were noted. CONCLUSIONS: Screw-retained implant-supported metal-ceramic crowns demonstrated a significantly lower porcelain fracture resistance than cement-retained crowns. Placing the screw access opening 1 mm offset from the center of the occlusal surface did not result in lower fracture resistance. Cement-retained crowns with 4- or 5-mm buccolingual width of the occlusal surface showed similar porcelain fracture resistance.

Analysis of Variance↗
PubMed2004

Fabrication of a cement- and screw-retained implant prosthesis.

The advantages of cement-retained implant-supported restorations over screw-retained implant restorations are well documented. Difficulty with prosthesis retrieval and excess cement removal may be experienced with cemented restorations. The technique described allows for the fabrication of a retrievable cemented prosthesis that is simple, practical, and effective.

Cementation↗
PubMed2005

An immediately loaded CAD/CAM-guided definitive prosthesis: a clinical report.

Dental implants have had a major impact on the treatment of edentulous patients. Fixed complete dentures have allowed removable complete dentures to be replaced with fixed prostheses. A new treatment modality using immediately loaded implants placed with a CAD/CAM surgical template using a flapless surgical technique, then loaded with a prefabricated restorative prosthesis, is presented. This report describes the Teeth-in-an-Hour (Nobel Biocare, Yorba Linda, Calif) treatment provided for a patient.

Computer-Aided Design↗
PubMed2005

Three-dimensional finite element analysis of the effect of different bone quality on stress distribution in an implant-supported crown.

STATEMENT OF PROBLEM: Primary implant stability and bone density are variables that are considered essential to achieve predictable osseointegration and long-term clinical survival of implants. Information about the influence of bone quality on stress distribution in an implant-supported crown is limited. PURPOSE: The purpose of this study was to investigate the effect of 4 different bone qualities on stress distribution in an implant-supported mandibular crown, using 3-dimensional (3-D) finite element (FE) analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar tooth was developed, and an implant to receive a crown was developed. A solid 4.1 x 10-mm screw-type dental implant system (ITI; solid implant) and a metal-ceramic crown using Co-Cr (Wiron 99) and feldspathic porcelain were modeled. The model was developed with FE software (Pro/Engineer 2000i program), and 4 types of bone quality (D1, D2, D3, and D4) were prepared. A load of 300 N was applied in a vertical direction to the buccal cusp and distal fossa of the crowns. Optimal bone quality for an implant-supported crown was evaluated. RESULTS: The results demonstrated that von Mises stresses in D3 and D4 bone quality were 163 MPa and 180 MPa, respectively, and reached the highest values at the neck of the implant. The von Mises stress values in D1 and D2 bone quality were 150 MPa and 152 MPa, respectively, at the neck of the implant. A more homogenous stress distribution was seen in the entire bone. Conclusion For the bone qualities investigated, stress concentrations in compact bone followed the same distributions as in the D3 bone model, but because the trabecular bone was weaker and less resistant to deformation than the other bone qualities modeled, the stress magnitudes were greatest for D3 and D4 bone.

Aluminum Silicates↗
PubMed2005

Achieving immediate function with provisional prostheses after implant placement: a clinical report.

When using a conventional implant treatment protocol in edentulous patients, reduced function and comfort for up to 6 months after implant surgery is inevitable until bone healing is complete and a prosthesis is securely attached to the implants. The following report highlights 2 treatment modalities that enable immediate function by inserting provisional prostheses immediately after implant placement.

Aged↗
PubMed2005

Custom-made laser-welded titanium implant prosthetic abutment.

A technique to create an individually modified implant prosthetic abutment is described. An overcasting is waxed onto a machined titanium abutment, cast in titanium, and joined to it with laser welding. With the proposed technique, a custom-made titanium implant prosthetic abutment is created with adequate volume and contour of metal to support a screw-retained, metal-ceramic implant-supported crown.

Ceramics↗