Prosthodontic criteria for maxillary immediate occlusal loading, surgical classifications of atrophic maxillae, and presentation of a new implant/anatomic classification system for immediate maxillary rehabilitation.

PURPOSE: Immediate full-arch occlusal loading for patients with atrophic edentulous maxillae satisfies critical needs for this specific type of edentulous patient after placement of implants with high levels of primary implant stability. The needs include improved aesthetics, limited immediate improved function, and elimination of removable prostheses. Classification systems exist for edentulous maxillae but they do not include specifics regarding posterior implant placement. In conjunction with anterior implants, posterior implants improve Anterior/Posterior (A/P) spreads, decrease cantilevered segments (CLs), and likely will improve implant and prosthetic success rates. The purposes of this article include presenting a new classification system that outlines the different types of implants now available which will likely achieve the requisite primary stability for immediate fixed rehabilitation. This proposed classification system identifies a relationship between different implant options currently available and the remaining quantity of bone in the first and second maxillary molar zones. MATERIALS AND METHODS: The available literature regarding current classification systems was reviewed. The benefits and limitations of each system were described. The parameters associated with Immediate Occlusal Loading (IOL) for full arch maxillary prostheses include: posterior cantilever lengths of full arch fixed prostheses; existing A/P spread considerations for full arch prostheses; and introduction of a new classification system for atrophic posterior maxillary edentulous ridges were identified. RESULTS: Currently, there are no available classification systems that outline specific implant options for posterior maxillae which will likely achieve the minimum primary stability needed for immediate rehabilitation. A new classification system was proposed where the rationale was to show clinicians that when a certain amount of bone remains in the posterior maxilla, there are specific implants designed to maximize primary stability. High implant primary stability is required for rehabilitation with immediate fixed implant-supported provisional prostheses. The proposed classification system assists clinicians in understanding what implant geometry is available and can be expected to achieve the requisite primary stability for immediate occlusal loading based on the available bone in the posterior maxillary molar zone. CONCLUSIONS: This article reviewed current classification systems for edentulous maxillary patients, as well as clinical parameters required for full arch, immediate occlusal loading.  It also presented a new classification system to assist clinicians in selecting appropriate implants and surgical techniques for immediate fixed rehabilitation of patients with atrophic maxillae.

Immediate rehabilitation of severely atrophic maxillae using conventional and extended length subcrestal angulated (ELSA) implants: A retrospective analysis of 187 implants in 33 patients with up to three years of function.

PURPOSE: The purpose of this study was to evaluate and determine clinical outcomes and survival rates of straight and extended length subcrestal angulated (ELSA) implants (20-24 mm lengths) placed for immediate (up to 72 h post-operative) or delayed rehabilitation (4 months post-operative) of severely atrophic maxillae. Prosthetic treatment consisted of interim and definitive implant-supported fixed implant-supported prostheses with up to 3 years of function. MATERIALS AND METHODS: A retrospective analysis was conducted of 38 patients (five dropped out; final total was 33), treated between 2017 and 2019 in a private practice. Extended length subcrestal angulated (ELSA) implants and conventional endosseous straight implants (Southern Implants, Irene, South Africa) with (fixed) full arch prostheses were used to restore patients with edentulous maxillae immediately (within 72 hs) or delayed (4 months).  ELSA implants have subcrestal angulations of 24° and 36° of the restorative platforms, external hexagon crestal anti-rotation abutment connections, and lengths between 18 and 26 mm. Implant loading was determined by implant insertion torque values (as determined on the surgical units); 120 Ncm was the threshold level for immediate loading. Clinical and radiographic examinations were done that recorded the clinical outcomes of implants and prostheses. SPSS was used to process the data. RESULTS: Thirty-three patients and 187 implants were included with follow-up periods of at least 12 months (range 12-36 months). The mean age of the study population was 62.6 ± 8.4 years old (at the time of implant placement). Thirty-three patients (86.8%) were followed for 12 months; 13 patients (39.4%) were followed for 24-35 months; 9 patients (27.3%) were followed for 36 months. In total, 13 implants in six patients failed secondary to sinus infections. Mean bone levels (MBLs) were respectively: 0.88 ± 2.12 mm at loading, -1.53 ± 2.03 mm at 12 months, -2.26 ± 1.45 mm at 24 months, and -2.54 ± 1.46 mm at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBL at 36 months than did the conventional implants. One hundred thirty-seven implants were placed and loaded within 72 h; 50 implants were placed and loaded 4 months post placement. The combined implant survival rates were 93.0% at 12 months, 91.1% at 24 months, and 100% at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBLs at 36 months when compared to the conventional implants. CONCLUSIONS: The results of this retrospective clinical chart review indicated that the use of ELSA implants placed into anterior maxillae and nasal crests with accentuated distal tilts (>30°) and simultaneous sinus augmentation provided favorable outcomes for prosthetic rehabilitation in patients with severe atrophic maxillae. ELSA implants placed with simultaneous sinus augmentation are an alternative option to zygomatic implants (ZI) when immediate loading is prescribed. Sinus infections were thought to be the proximate causes of all implant failures. Further long-term clinical studies are warranted with larger patient populations.

Immediate dentoalveolar restoration (IDR) of central maxillary incisor using sinus lateral wall block graft to regenerate loss of facial and palatal bone: Literature review and 1 year follow-up.

Replacement of missing or hopeless teeth in the esthetic zone is one of dentistry's most critical challenges. In the past, multiple surgical procedures have been needed to reconstruct compromised extraction sites. The surgeries have been associated with long healing times and increased morbidity, all the while patients are using either fixed or removable interim restorations. The procedures identified in this paper minimize surgical operating times, healing times, and delays in obtaining definitive restorations by combining multiple surgical procedures in one visit. The procedures are technique sensitive. This particular patient has been followed for 1 year post-operatively with clinical photographs and CBCT scans. Excellent clinical results were obtained. Benefits and limitations of the procedures have also been identified.

Accuracy of merging scans of definitive fixed prosthodontic impressions to obtain single, accurate digitized master casts.

PURPOSE: Many elastomeric impressions sent to commercial laboratory dental technicians may include marginal defects. To fabricate accurate restorations, digital technology may be used to merge digital files of defective impressions into a single standard tessellation language (STL) file free of errors. This would save clinicians and patients time and may improve clinical care. The purpose of this study was to compare the accuracy of digital master casts reconstructed from merged STL files of defective impressions with the file of the original defect-free preparations. MATERIAL AND METHODS: Ivorine teeth on a dentoform were prepared to receive a posterior fixed dental prosthesis (FDP) with complete coverage preparations. An impression was made in a stock tray using polyvinyl siloxane (PVS) impression material and an extraoral scanner (E3, 3Shape, Denmark) was used to digitize the impression; this was the reference cast. Wax was used to create defects on the buccal and lingual margins of the preparations. Fifteen PVS impressions were made of the FDP preparations with defects in the mesial and distal margins; another set of 15 PVS impressions was made of FDP preparations with defects in the buccal and palatal margins for a total of 30 impressions. All impressions were digitized using the same extraoral scanner (E3, 3Shape, Denmark). Corresponding STL files were paired and merged, and a master cast was created by eliminating the defects using the scanned data. This master cast was compared to the reference cast using reverse engineering software (Geomagic, Morrisville, NC, USA). The results were expressed as average errors and standard deviations in the master casts relative to the reference cast. To account for the presence of positive and negative values in the data set, in terms of errors, the root mean square (RMS) value was calculated for each sample. RESULTS: The mean average error in the sample was -0.4 µm. The average upper limit of 95% confidence interval was +36.5 µm, while the average lower limit of 95% confidence interval was -37.3 µm. The mean RMS of the errors found was 18.9 µm. CONCLUSIONS: The results of this study indicated that merging digitized definitive impressions to correct marginal defects resulted in master casts with a high level of accuracy relative to the reference cast.

Shear bond strength characteristics on surface treatment modalities of CAD-CAM resin polymers.

PURPOSE: The purpose of this in vitro study was to analyze the shear bond strength of composite resin to a commercially available high-performance polymer material for fixed, screw-retained full arch restorations. MATERIAL AND METHODS: A total of 135 computer-aided design and computer-aided manufacturing, high-performance polymer (HPP) blocks were cut and obtained from discs (Trilor 95, Harvest Dental, Brea, CA). The samples were 10 mm × 10 mm × 10 mm. The specimen surfaces were grouped as untreated (Group A), 50 µm Al2O3 (Group B), 110 µm Al2O3 (Group C), Rocatec (3 M, St. Paul, MN) activated with silica-modified alumina oxide treatment (Group D); and trimmed coarsely with a carbide bur (Group E). Group A samples were used as controls. After surface treatments, the specimens were gently cleansed with oil-free steam and alcohol wipes. Surface conditioning was performed on all physically treated samples.  The manufacturer's recommendations were followed for bonding composite resin to the samples with light-cured Visio.link (Bredent, Chesterfield, UK). Cylinders were veneered with composite resins (diameter 5 mm, height 4 mm) and polymerized on the specimen surfaces through plastic tubes. Twenty-seven specimens were used for each testing group and aging tests were performed. The experimental samples were thermocycled.  Shear bond strength and scanning electron microscopic tests were performed. Means and standard deviations were calculated.  Statistical analysis was performed with post-hoc Tukey tests. RESULTS: Statistical analysis revealed that there was a significant difference between the groups (p<0.001). The highest shear bond strengths were achieved for the specimens bonded with Visio.link without physical surface treatments (270.47 MPa). The lowest bond strengths were found for specimen surfaces abraded with 110 µm Al2O3 (117.03 Mpa) CONCLUSIONS: The results of this laboratory study indicated that the specimens used with Visio.link as provided by the manufacturer had the highest shear bond strengths between the composite resin and high-performance polymer test specimens. Modifications of the high-performance polymer surfaces with carbide burs did not change bonding strengths with the composite materials.

Double sleeve guided placement of quadruple zygomatic implants for rehabilitation of a patient with ectodermal dysplasia: A clinical report.

The surgical and prosthodontic treatment for a 22-year-old man with ectodermal dysplasia is described and illustrated. He had never managed to wear complete dentures, and implant-retained or implant-supported prostheses were indicated. However, the placement of conventional maxillary endosseous implants was contraindicated. A novel surgical template with double sleeves was used to guide osteotomies for 4 zygomatic implants used with an unloaded, one-stage approach. After confirming osseointegration, prosthetic rehabilitation began with an interim implant-supported fixed prosthesis to evaluate esthetics, phonetics, and hygiene maintenance. Clinical challenges included lip biting and speech articulation.

Survival Rate of Ultrawide Diameter Implants Placed into Molar Postextraction Sockets and in Function for Up to 144 Months.

PURPOSE: Innovations in macroimplant design, specifically ultrawide implants 7.0 mm or greater in diameter, have allowed immediate molar replacement. This is a retrospective study assessing the survival rates of ultrawide diameter implants (7.0, 8.0, 9.0 mm) immediately placed into molar extraction sockets. Implants were followed up to 144 months postplacement. MATERIALS AND METHODS: A retrospective study was conducted of all patients treated in a private surgical practice between January 1, 2008 and December 31, 2020, who received ultrawide dental implants (7.0, 8,0, 9.0 mm.) placed immediately into molar extraction sockets. Wide diameter healing abutments were placed on all implants at the time of surgery. Abutments and crown restorations were fabricated after at least 4 months of unloaded healing. Patient age, sex, implant location and implant diameters were examined for survival. Insertion torque values at the time of placement and time in function were also evaluated. Biometric statistics were computed with p-values (<0.05. Descriptive and bivariate statistics were computed; p-values were set at 0.05. RESULTS: Five hundred forty-four patients (225 males; 319 females) average age 62.5 years (range 27 to 95) had 563 implants placed. Five hundred thirty-five of five hundred sixty-three (535/563) implants survived; 28 failed [clinical survival rate (CSR) 95.03%]. Number and time in function were: 0 to 12 years 100%; 0 to 9 years 85%; 0 to 6 years 69%; 0 to 3 years 35% or 10 to 12 years 16%; 7 to 9 years 16%; 4 to 6 years 34%; 0 to 3 years 35%. No significant differences were found between sex and implant failures (p = 0.22). Maxillary (266/285; 93.3%) and mandibular (269/278; 96.8%) implant CSRs were not significantly different. Three implant diameters were used: 7.0 mm (206/563) [36.6%]; 8.0 mm (267/563) [47.4%]; 9.0 mm (90/563) [15.9%]. Clinical survival rates were: 7.0 mm (201/206) [97.6%]; 8.0 mm (252/267) [94.4%]; 9.0 mm (82/90) [91.1%]. Mean age for patients with failed implants did not show any significant differences (p = 0.1398). Fifteen of the 28 failed implants failed within 120 days of surgical placement (prior to definitive restoration; [53.6%]; 4 implants failed between 4 and 12 months [14.3%]; 9 implants failed at least 1-year postloading [32.1%]. CONCLUSIONS: The results of this long-term retrospective study regarding ultrawide diameter implants suggested that these implants were viable treatment options for immediate molar replacement following tooth extraction in either jaw with an unloaded healing protocol. High clinical survival rates were reported over a 144-month (12-year) timeframe.

Full arch immediate occlusal loading using site specific implants: A clinical series of 10 patients (13 arches).

PURPOSE: Osseointegration of dental endosseous implants has proven to be effective, predictable, and clinically successful. Unloaded healing protocols were originally used in treating edentulous patients. Full arch immediate occlusal loading protocols have been shown to be as effective as unloaded healing protocols. This paper reports on the results, benefits, and limitations of one specific immediate loading protocol using site specific implants for fresh extraction and healed extraction sites. MATERIALS AND METHODS: Ten consecutive patients [{13 arches} (age range: 64-81 years; average: 70.1) (4 males/6 females) were treated by the first 2 authors in private practice settings. Hopeless teeth were scheduled for extraction with immediate implant placement and immediate loading with insertion of full arch, screw-retained, acrylic resin interim prostheses within 24 hours. Implants were also placed into healed edentulous ridges. Insertion torque values for each implant were recorded. Interim prostheses were removed after at least 3 months of healing. Implants were reverse torque tested (35 Ncm) and evaluated for macroscopic mobility. Definitive full arch prostheses were made. Patients were followed for 21 to 48 months postimplant surgery. Panoramic radiographs were taken immediately postimplant placement and 1 year postoperative. RESULTS: Thirteen arches were treated; 11 ultrawide diameter implants were placed into molar sockets, 26 inverted body-shift implants were placed into anterior sockets; 25 standard diameter, tapered implants were placed into edentulous sites; 2 zygomatic implants were placed in one patient. The total number of implants placed was 64 (4 preexisting implants were also used and not included in this study). The minimum implant insertion torque value was 20 Ncm. After 12 to 18 months of function (average 14 months), the implant and prosthetic survival rates were 100%. Eight patients were restored with definitive zirconia or acrylic resin hybrid fixed prostheses. Two patients were restored with bar titanium frameworks and removable overdenture prostheses. No prosthetic complications were reported for the definitive prostheses. CONCLUSIONS: The results of this clinical series with site specific implants and immediate full arch occlusal loading in treating edentulous patients resulted in 100% clinical implant and prosthetic survival rates. According to this study, this protocol can be used with high levels of anticipated success.

In vitro study of surface alterations to polyetheretherketone and titanium and their effect upon human gingival fibroblasts.

STATEMENT OF PROBLEM: Soft-tissue attachment to different surfaces may play a pivotal role in the long-term success of dental implants. However, studies on the issue, especially on newer materials, are sparse. PURPOSE: The purpose of this in vitro study was to evaluate the viability and adhesion of human gingival fibroblasts (HGFs) on different implant abutment materials with specific surface modifications. MATERIAL AND METHODS: One hundred and fifty specimens in 6 experimental groups were evaluated: smooth-machined titanium alloy (Ti), laser-modified titanium (TiL), smooth-machined polyetheretherketone (PEEK) (P), laser-modified PEEK (PL), plasma-treated PEEK (PP), laser- and plasma-treated PEEK (PLP). Machined Ti was considered as the control group. Surface roughness (Sa), water contact angle (WCA), and X-ray photoelectron spectroscopy (XPS) were measured. HGF attachment and proliferation were observed at 1, 3, and 7 days after cell seeding. Comparison of the means among the groups was performed with 1-way analysis of variance (ANOVA) with post hoc comparison using the Tukey test (α=.05). RESULTS: Sa values of the laser modified groups were significantly higher than those of the nonmodified (smooth-machined) groups (P<.001). WCAs were significantly different among PEEK groups, and plasma-sprayed groups had the lowest WCAs. XPS analysis of both Ti and PEEK groups showed laser treatment did not have any significant effect on the surface composition of the PEEK as the same bonds with similar ratio/fraction were detected in the spectrum of the modified specimens. Scanning electron microscopy (SEM) revealed more functionally oriented HGF cells on the laser-grooved surfaces. On the first, third, and seventh day of proliferation, the titanium groups showed no significant differences (P>.05). On the first and third days of proliferation, the plasma sprayed groups (PP, PLP) showed significantly greater proliferation than all experimental groups (P<.001). On the seventh day of proliferation, statistically significant differences were observed between all PEEK groups and between all PEEK groups and the Ti group (P<.001), with the exception of the PL and P groups and the PLP and Ti groups (P>.05). CONCLUSIONS: Laser-modified titanium and PEEK surfaces led to guided gingival fibroblast attachment. Plasma treatment of PEEK surfaces increased the wettability of this polymer and improved proliferation of HGF.

A Novel Approach for Converting a Mandibular Complete Denture to a Fixed Interim, Screw-Retained Implant Prostheses: A Case Report.

For most of the last century, conventional complete dentures have been the standard of care and the most common treatment for edentulous patients. Technological advancements in fabrication techniques may significantly reduce the number of office visits required to fabricate complete dentures. Immediate occlusal loading with mandibular full arch prostheses has been extensively researched and is now one of the standards of care for edentulous patients. A clinical technique for converting a mandibular immediate complete denture to an interim full arch, screw-retained fixed prosthesis with novel implant restorative components for immediate loading on four implants is described.

Clinical Outcomes of Maxillary Anterior Postextraction Socket Implants with Immediate Provisional Restorations Using a Novel Macro-Hybrid Implant Design: An 18- to 24-Month Single-Cohort Prospective Study.

Extraction and immediate implant placement/restoration in the esthetic zone is clinically challenging; benefits include fewer surgical appointments and maintenance of peri-implant soft tissues throughout the treatment period, and limitations include gingival recession and bone dehiscence during surgery. Macro-hybrid implants (large-diameter apical/narrow-diameter occlusal) were placed in 19 patients immediately following the extraction of hopeless maxillary anterior teeth. Immediate restorations were fabricated without occlusal contacts. Pre- and postplacement cone beam computed tomography (CBCT) scans were taken. Nineteen implants were available for recall 13 to 25 months postoperatively. The overall implant cumulative survival rate was 100% (range: 13 to 25 months, mean: 19 months), and mean insertion torque value was 65 Ncm. Mean Pink Esthetic Score was 12.63 at 6 months, and was 13 at the 18- to 24-month follow-up. Mean mesial and distal tooth-to-implant distances immediately after implant placement were 2.55 ± 1.29 mm and 2.29 ± 0.82 mm, respectively. Interproximal bone crest width, distance, and height were maintained at implant platforms, mesially and distally, 18 to 24 months postoperative. The results of this study indicated that the macro-hybrid implant geometry for this immediate surgical/restorative protocol provided excellent and stable 2-year results relative to implant survival (100%), labial plate thickness via CBCT evaluations, tooth-to-implant distances immediately post-implant placement, PES, and interproximal bone crest width, distance, and heights, which were maintained at the implant platforms.

Comparison of nonscheduled, postinsertion adjustment visits for complete dentures fabricated with conventional and CAD-CAM protocols: A clinical study.

STATEMENT OF PROBLEM: Unscheduled denture-adjustment visits may disrupt both patients and clinicians. Denture-adjustment visits have not been correlated with denture-processing methods. PURPOSE: The purpose of this clinical study was to identify differences in the number of unscheduled postinsertion-adjustment visits of patients with complete dentures fabricated by injection molding (IM) versus dentures fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM). MATERIAL AND METHODS: One hundred six participants were evaluated in the study. They were consecutively treated in a private practice setting and followed up for 1 year after the insertion of new complete dentures. The first 33 received dentures fabricated using an IM system, and the other 73 were milled using a CAD-CAM system. All participants had been edentulous for at least 1 year. Participant ages ranged from 29 to 83 years. IM dentures were fabricated by a commercial dental laboratory; CAD-CAM dentures were milled by a commercial manufacturer. All participants were scheduled for 1- or 2-week postinsertion office visits. Further adjustment visits were scheduled according to participant request. The results were tabulated, and univariable tests of association were performed including chi-square and the Fisher exact tests for categorical comparisons and the Wilcoxon rank sum test for comparison of ordinal continuous data. A multivariable logistic regression model was used to control for the influence of multiple predictor variables on the outcome of interest. RESULTS: Edentulous years ranged from 1 to 60. Approximately one half (n=56) of all participants returned for scheduled postinsertion visits approximately 1 to 2 weeks after insertion of the dentures. No significant demographic or clinical differences were noted between participants receiving CAD-CAM or conventional dentures. Return visits for unscheduled adjustments were not associated with the method of denture fabrication or any other demographic features (P=.55). CONCLUSIONS: Based on the results of this study, there were no significant differences in the number of unscheduled, postinsertion visits for participants whose dentures were fabricated following IM or CAD-CAM milling protocols. Clinicians may choose to fabricate complete dentures with either protocol and expect similar clinical results in terms of the number of unscheduled postinsertion visits.

Effect of finish line design and metal alloy on the marginal and internal gaps of selective laser melting printed copings.

STATEMENT OF PROBLEM: Selective laser melting (SLM) technology has been introduced for printing metal dental restorations from Co-Cr base alloys or Au-Pt high noble alloys. However, information regarding the fit of restorations fabricated by using this technique is limited. PURPOSE: The purpose of this in vitro study was to determine the effect of 3 different finish line designs on the marginal and internal gaps of metal copings made from a base (Co-Cr), high noble (Au-Pd-Ag), and noble alloy (Co-Pd) by using the SLM technology. MATERIAL AND METHODS: Three Ivorine right maxillary central incisors were prepared with a chamfer, deep chamfer, or shoulder finish line. The preparations were scanned by using a TRIOS scanner, and a total of 90 dies were printed using DPR 10 Resin (30×3 finish line designs). Ten SLM copings were fabricated for each margin design and metal alloy combination for a total of 90 copings (10×3 finish line designs×3 alloys). Copings were cemented onto dies using an autopolymerizing composite-resin luting material. All coping-die assemblies were sectioned buccolingually by using a low-speed diamond saw, and images were obtained by using an inverted bright field metallurgical microscope at ×100 magnification. Marginal and internal gaps were measured at 5 locations: buccal margin, midfacial, incisal, midlingual, and lingual margin. After gap measurements, representative specimens were embedded in autopolymerizing resin and prepared for metallographic examination. A 2-way multivariate analysis of variance (MANOVA) was conducted to determine the overall significance, followed by ANOVA for each dependent variable (α=.05). RESULTS: The results indicated that alloy type and finish line had a significant influence on marginal gap of copings (P<.001). Relative to the internal gap, alloy type had a significant effect (P<.001), but the type of finish line had no statistically significant influence (P=.337). No statistically significant interactions occurred. Base alloys were printed with almost no observable porosity, whereas noble and high noble alloys exhibited hot tears and porosity. CONCLUSIONS: Thefinish line type did not influence the internal gap between copings and dies, whereas the alloy type influenced the marginal gap between copings and dies. SLM-fabricated Co-Cr copings on teeth prepared with a deep chamfer finish line demonstrated the lowest marginal gap.

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 study's framework designs for full-arch, titanium milled frameworks (CL/AP ratio <1), resulted in consistent, predictable results for rehabilitating edentulous patients.

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 (CFI's) have lower cumulative survival rates (CSR's) than intraoral endosseous implants, osseointegrated CFI's have proven to be significant adjuncts to improving retention of maxillofacial prostheses. However, CSR's of CFI's have been reported to be lower than CSR's 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 (CSR's) reported for CFI's and to illustrate the treatment of a maxillofacial patient using CFI's and a CAD/CAM copy-milled framework for retention and support of a nasal prosthesis.

Comparison of the accuracy of Biomet 3i Encode Robocast Technology and conventional implant impression techniques.

PURPOSE: To compare the accuracy of implant master casts fabricated using Robocast Technology (Biomet 3i) with that of master casts fabricated using traditional transfer (closed-tray) and pick-up (open-tray) techniques. MATERIALS AND METHODS: A stereolithographic replica of a Kennedy Class I human mandible was fabricated for use as the master model. Implants were placed into both posterior quadrants (both second premolars and second molars) and set parallel (P) on one side and divergent (nonparallel, NP) on the opposite side. Impressions were made of the master model (patient replica model) with Encode Healing Abutments, open-tray, and closed-tray impression copings. Identical metallic spheres were placed onto each implant analog in the stone master casts, and the casts/spheres were scanned using a digital scanner. Measurements were made between the center points of the spheres and compared to the master model. Data were divided into P, NP, and individual sites, and the differences were analyzed statistically (α = .05). RESULTS: Encode master casts were less accurate than the open-tray casts in NP sites. Encode master casts were less accurate than the open-tray and closed-tray casts in P sites. NP sites demonstrated less accuracy than P sites within the Encode group. Encode master casts were less accurate than the open- and closed-tray casts at the mandibular right second premolar site. The mandibular left second premolar was less accurate than the mandibular right second molar in the Encode group. CONCLUSIONS: Within the limitations of this lab-based study and analysis, the Encode technique resulted in master casts that were less accurate than master casts made from traditional open- and closed-tray impression techniques. Further research is necessary before specific clinical judgments can be made.

Maintenance of implant hybrid prostheses: clinical and laboratory procedures.

Fixed implant hybrid prostheses have been used for the last 40+ years in the treatment of edentulous patients. These prostheses have provided long-term masticatory function for thousands of patients. The original treatment protocol included fabrication of cast metal frameworks that fit accurately on the restorative platforms or abutments and/or endosseous implants. Frameworks were designed to splint implants together; they also provided retention and support for the functional and esthetic portions of the fixed hybrid prostheses. Initially, edentulous patients were treated with maxillary complete dentures and mandibular fixed, hybrid prostheses. Denture teeth were used in both prostheses. Over the span of many years, occlusal surfaces of the denture teeth in the mandibular prostheses exhibited signs of occlusal abrasion and wear, sometimes completely abrading the teeth and denture bases, resulting in framework exposures. Ultimately, this resulted in decreased chewing efficiency and loss of vertical facial height. Patients would then return to clinicians and ask for retreatment. In certain instances, the underlying frameworks would have to be remade. This involved replicating the original series of appointments and significant additional expense to patients and clinicians alike. The protocol presented in this article avoids having to remake the most expensive portion of fixed implant prostheses--the frameworks. The protocol identifies the clinical and laboratory procedures involved in using existing frameworks and replacing preexisting denture bases and denture teeth, with minimal inconvenience to patients.

Accelerated treatment protocols: full arch treatment with interim and definitive prostheses.

With the advent of titanium, root form implants and osseointegration, dental treatment has undergone a metamorphosis in recent years. These new techniques enable dentists to provide anchorage for various kinds of prostheses that improve masticatory function, esthetics, and comfort for patients. Implant treatment protocols have been improved relative to implant macro- and micro-geometries, surgical and prosthetic components, and treatment times. Over the past 20 years, immediate occlusal function (also known as loading) has been established as a predictable treatment modality, provided certain specific criteria are met. In many cases, edentulous patients, crippled by the loss of their teeth, can undergo outpatient surgical and prosthetic procedures and return to a masticatory function that is near normal--sometimes after only one day of surgical and prosthetic treatment. This treatment option is also available for patients with advanced, generalized periodontal disease. Computer-assisted design/Computer-assisted manufacturing (CAD/CAM) has transformed how dental prostheses are made, offering improved accuracy, longevity, and biocompatibility; along with reduced labor costs and fewer complications than casting technologies. This article reviews the principles associated with immediate occlusal loading and illustrates one specific accelerated prosthodontic treatment protocol used to treat edentulous and partially edentulous patients with interim and definitive prostheses.