Carl Drago

Cantilever Lengths and Anterior-Posterior Spreads of Interim, Acrylic Resin, Full-Arch Screw-Retained Prostheses and Their Relationship to Prosthetic Complications.

PURPOSE To retrospectively record the distal cantilever lengths (CL) of full-arch interim, all-acrylic resin prostheses used in an immediate occlusal loading protocol. Anterior/posterior (A/P) spreads were measured on master casts associated with the interim prostheses. Ratios were calculated (CL/AP). Prosthetic complications were recorded. The ratios and prosthetic complications were statistically compared and analyzed for statistical and clinical significance. MATERIALS AND METHODS One hundred twenty-eight patients with 192 edentulous arches (109 maxillary; 83 mandibular; 190 arches were restored with 4 implants; 2 maxillary arches were restored with 5 implants) were treated. Seven hundred seventy implants (Brånemark System) from September 1, 2011, until August 31, 2013 were included in this report. Patients were treated and followed in a single private practice for up to 40 months. Implants had to have at least 35 Ncm of insertion torque to be immediately loaded. All implants were immediately loaded with full functional occlusions on the day the implants were placed. Interim, full-arch, all-acrylic resin prostheses were fabricated and placed into full functional occlusion following an All-on-Four protocol. Measurements of the distal cantilevered segments were made on the prostheses prior to insertion. A/P spreads were measured on the master casts made from abutment level impressions made on the day of surgery. Prosthetic complications (denture base fracture, cohesive/adhesive denture tooth fractures) were recorded in the charts as they occurred. All charts were reviewed for this report; no patients were lost to follow-up. Interim prosthetic repairs were analyzed by type (tooth or denture base), arch, gender, and location within the edentulous arches. RESULTS One patient experienced complete maxillary implant failure; the overall implant survival rate (SR) was 99.5% (766 of 770). Four hundred thirty of 434 maxillary implants and 336 of 336 mandibular implants survived for SRs of 99.1 and 100%, respectively. Thirty four of the 192 interim prostheses (17.7%) warranted at least one repair during treatment. The average cantilevered segments for the interim maxillary prostheses without prosthetic complications were 9.7 mm (right) and 9.5 mm (left). The average cantilevered segments for the repaired maxillary prostheses were 10.1 mm (right); 9.9 mm (left). The average cantilevered segments for the interim mandibular prostheses without prosthetic complications were 9.2 mm (right) and 9.3 mm (left). The average cantilevered segments for the repaired mandibular prostheses were 9.87 mm (right) and 9.18 mm (left). The average maxillary A/P spread was 18.4 mm; the average mandibular A/P spread was 17.3 mm. The average maxillary CL/AP spread ratios were 0.55 (right) and 0.53 (left); the average mandibular CL/AP spread ratios were 0.61 (right) and 0.57 (left). There were no statistical correlations between the CL/AP ratios and the frequency or type of prosthetic repairs recorded in this study. The ratios were statistically significant (p = 0.041) for mandibular prostheses with prosthetic complications: slightly greater CL/A-P ratios were noted. CONCLUSIONS The results from this 2-year clinical retrospective analysis indicated that CL/AP ratios in the range of 0.5 to 0.6 generally resulted in successful interim prostheses during the time the interim prostheses were in function. The results of this investigation also revealed that 1 of 129 patients experienced implant failures; implants placed and restored on the same day with full-arch, screw-retained prostheses resulted in high clinical survival rates for implants and prostheses. The All-on-Four treatment protocol used in this study was a viable alternative to other implant loading/placement protocols for rehabilitating edentulous patients and resulted in minimal prosthetic complications.

Frequency and Type of Prosthetic Complications Associated with Interim, Immediately Loaded Full-Arch Prostheses: A 2-Year Retrospective Chart Review.

PURPOSE The purpose of this report was to retrospectively evaluate implant and immediate full-arch prosthesis survival rates over a 24-month period; patients were consecutively treated with immediate occlusal loading. Dental arch, gender, and implant orientation (vertical vs. tilted) were also noted. MATERIALS AND METHODS All Brånemark System implants (Nobel Active) and interim, all-acrylic resin prostheses placed in patients following an All-on-Four™ protocol, in a single private practice were assessed by retrospective patient chart review. The amount of space provided surgically for implant restorative components and prostheses was determined from measurements of the vertical heights of the interim prostheses in the right/left anterior and posterior segments. These measurements were made in the laboratory. Interim prosthetic repairs (type, frequency, length of time from insertion) were analyzed by type, arch, gender, and implant orientation. Implant survival and insertion torque values were also measured. Inclusion criteria consisted of all Brånemark System implants placed with the All-on-Four protocol from September 1, 2011, until August 31, 2013. Specific dietary instructions were given for the first 7 days immediately postoperatively and for the weeks prior to insertion of the definitive prostheses. RESULTS One hundred twenty-nine patients, comprising 191 arches (766 implants) from September 1, 2011, until August 31, 2013, were included in the study. One patient experienced implant failure yielding an overall implant survival rate (SR) of 99.5% (762 of 766). Four hundred twenty-six of 430 maxillary implants and 336 of 336 mandibular implants survived for SRs of 99.1% and 100%, respectively. Regarding implant orientation, 415 of 417 tilted implants (SR 99.5%) and 343 of 345 (CSR 95.6%) vertical implants were noted to be clinically stable. Interim, all-acrylic resin prostheses were in place for a mean of 199.2 days; mandibular prostheses were in place for an average of 195.4 days; maxillary prostheses were in place for an average of 202.0 days. Thirty four of the 191 interim prostheses (17.8%) warranted at least one repair during the treatment period. The average overall implant insertion torque value was 60.74 Ncm; mandibular torque values averaged 63.08 Ncm; maxillary torque values averaged 59.00 Ncm. CONCLUSIONS The results from this study suggest that dental arch, gender, and implant orientation for implants placed and immediately restored with interim, all-acrylic resin, full-arch prostheses per the All-on-Four protocol did not have significant statistical or clinical effects on prosthetic complications of the interim prostheses or implant survival. Only one of the 129 patients experienced implant failures, indicating that the All-on-Four treatment protocol used in this study is a viable alternative to other protocols for rehabilitating edentulous patients.

Prosthetic Reconstruction of a Patient with an Acquired Nasal Defect Using Extraoral Implants and a CAD/CAM Copy-Milled Bar

Traditionally, patients with maxillofacial defects have been challenging to treat. A multitude of challenges associated with maxillofacial prosthetic treatment are not typically seen with patients who need conventional prosthodontic treatment. These types of patients generally require replacement of significant amounts of hard and soft tissues than do conventional prosthodontic patients. Most maxillofacial patients also warrant more emotional support than do conventional prosthodontic patients. Successful maxillofacial prosthetics still need to embrace the traditional goals of prosthodontic treatment: stability, support, retention, and esthetics. It is unlikely that a maxillofacial prosthesis will exactly duplicate the anatomy and function of missing or damaged structures. Although craniofacial implants (CFIs) have lower cumulative survival rates (CSRs) than intraoral endosseous implants, osseointegrated CFIs have proven to be significant adjuncts to improving retention of maxillofacial prostheses. However, CSRs of CFIs have been reported to be lower than CSRs for intraoral endosseous implants. Lately, computer-assisted design and computer-assisted machining (CAD/CAM) has been used in dentistry to facilitate fabrication of implant-supported frameworks. CAD/CAM protocols have numerous advantages over conventional casting techniques, including improved accuracy and biocompatibility, and decreased costs. The purpose of this paper is to review the literature on cumulative survival rates (CSRs) reported for CFIs and to illustrate the treatment of a maxillofacial patient using CFIs and a CAD/CAM copy-milled framework for retention and support of a nasal prosthesis.

Ratios of Cantilever Lengths and Anterior‐Posterior Spreads of Definitive Hybrid Full‐Arch, Screw‐Retained Prostheses: Results of a Clinical Study

PURPOSE To record the distal cantilever lengths (CL) of full-arch, definitive hybrid prostheses fabricated for patients after treatment with an immediate occlusal loading protocol. Anterior/posterior (AP) spreads were measured on master casts of the definitive prostheses. CL/AP ratios were calculated for these 2 parameters. These measurements were then compared and evaluated for statistical and clinical significance; the CL/AP ratios were also compared between definitive and interim prostheses. MATERIALS AND METHODS One hundred thirty patients with 193 edentulous arches (112 maxillary; 81 mandibular; 191 arches restored with 4 implants; 2 maxillary arches restored with 5 implants) were treated. Seven hundred seventy-four implants (Nobel Biocare Brånemark System [Nobel Active]) were included in this report. All but 2 patients had 4 implants placed into each jaw: the anterior implants were relatively vertical; the posterior implants were tilted parallel to the anterior wall of the maxillary sinus and angled distally above the mental foramen. Patients were treated and followed in private practice by the author. Implants had to have at least 35 Ncm of insertion torque to be immediately loaded. All implants were immediately loaded with full functional occlusions via interim, full-arch, all-acrylic resin prostheses. Definitive full-arch, hybrid prostheses were fabricated approximately 6 to 9 months after implant placement with computer-aided design/computer-aided manufacturing (CAD/CAM) frameworks, denture bases, and acrylic resin denture teeth. Measurements of the distal cantilevered segments were made with a Boley gauge on the interim and definitive prostheses prior to insertion. AP spreads were measured on the master casts made from abutment level impressions approximately 4 months post-occlusal loading. Prosthetic complications such as denture base fractures and cohesive/adhesive denture tooth fractures were recorded in the charts as they occurred. All charts were reviewed for this report. Prosthetic repairs for the definitive prostheses were analyzed by type (tooth or denture base), arch, gender, and location within the edentulous arches. RESULTS Patients were followed for up to 48 months post-immediate occlusal loading. One patient experienced maxillary implant failure; the overall implant survival rate (SR) was 99.5% (770 of 774). Four hundred forty-six of 450 maxillary implants and 324 of 324 mandibular implants survived for SRs of 99.1% and 100%, respectively. Thirty-three of the 193 interim prostheses (17.1%) warranted at least one repair during treatment. One of the 193 definitive prostheses demonstrated a posterior denture base fracture. The average cantilevered segments for the definitive maxillary prostheses were 15.6 mm (right) and 15.4 mm (left). The average cantilevered segments for the definitive mandibular prostheses were 15.5 mm (right) and 15.6 mm (left). The average maxillary AP spread was 18.4 mm; the average mandibular AP spread was 17.3 mm. Average maxillary CL/AP spread ratios were 0.85 (right) and 0.84 (left); average mandibular CL/AP spread ratios were 0.89 (right) and 0.90 (left). There were no statistically significant associations between the CL/AP ratios and the frequency or type of prosthetic repairs recorded in this study. CONCLUSIONS The results from this 4-year clinical retrospective analysis indicated that one of 130 patients experienced implant failures. The prosthetic complication rate for the definitive prostheses in this study was less than 1% (0.005). The author suggests that the parameters used in this studys framework designs for full-arch, titanium milled frameworks (CL/AP ratio <1), resulted in consistent, predictable results for rehabilitating edentulous patients.