“All-on-4” Immediate-Function Concept for Completely Edentulous Maxillae: A Clinical Report on the Medium (3 Years) and Long-Term (5 Years) Outcomes

The Accuracy of Computer-Assisted Implant Surgery Performed Using Fully Guided Templates versus Pilot-Drill Guided Templates

Purpose. Computer-assisted stereolithographically guided surgery allows an ideal implant placement for prosthetic restoration. Two types of stereolithographic templates are currently available: a fully guided template and a pilot-drill guided template. The purpose of this study was (i) to evaluate the accuracy of implant insertion using these types of surgical templates and (ii) to define parameters influencing accuracy. Materials and Methods. 20 patients were enrolled and divided into 2 study groups: in group A, implants were placed using CAD-CAM templates with fully guided sleeves; in group B, implants were placed with a template with only pilot-drill guided sleeves. Pre- and postoperative computed tomographies were used to measure differences between final positions of implants and virtually planned positions. Three linear discrepancies (coronal, apical, and depth) and two angular ones (buccolingual and mesiodistal) were measured. Correlations between accuracy and jaws of interest, implant length and diameters, and type of edentulism were also analysed. Results. A total of 50 implants were inserted in 15 patients using CAD-CAM templates: 23 implants in group A and 27 in group B. The mean coronal deviations were 1.16 and 1.11 mm (P = 0.35), respectively; the mean apical deviations were 1.65 and 1.71 mm (P = 0.22); the mean depth deviations were 0.95 and −0.68 mm (P = 0.032); the mean buccolingual angular deviations were 4.16° and 6.72° (P = 0.042); and the mean mesiodistal ones were 2.81° and 5.61° (P = 0.029). In addition, the accuracy was statistically influenced only by implant diameter for coronal discrepancy (P = 0.035) and by jaw of interest for mesiodistal angulation (P = 0.045). Conclusion. Fully guided implant surgery was more accurate than pilot-drill guided surgery for different parameters. For both types of surgery, a safety margin of at least 2mm should be preserved during implant planning to prevent damage to nearby anatomical structures.

The influence of prosthetic material on implant and prosthetic survival of implant-supported fixed complete dentures: a systematic review and meta-analysis

PURPOSE

Evaluating the impact of the prosthetic material on implant- and prosthetic survival of implant-supported fixed complete dentures.

STUDY SELECTION

Electronic and hand searches were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify clinical studies including at least 10 patients restored with implant-supported dentures. The primary outcome was to evaluate the implant survival rate according to the applied restorative materials. The prosthetic survival rate was evaluated as secondary outcomes.

RESULTS

Forty-one of 2254 studies were finally selected. A statistically significant difference (p = 0.0337) was found between implant survival rates in the main restorative groups (metal-ceramic:97%(95%CI [0.96;0.98]), all-ceramic:99%(95%CI [0.98;1.00]), metal-resin:97%(95%CI [0.96;0.98])). Prosthetic survival rates were: (metal-ceramic:95%(95%CI [0.89;0.97]), all-ceramic:97%(95%CI [0.92;0.99]), metal-resin:97%(95%CI [0.95;0.98]), with no statistically significant difference (p = 0.3796) between the groups. Chipping incidence rates were as follows: metal-ceramic:8%(95%CI[0.03;0.20]), all-ceramic:15%(95%CI [0.06;0.32]), and metal-resin:22%(95%CI [0.13;0.33]). Five types of exact restorative materials were identified (porcelain-fused-to-non-precious alloy, porcelain-fused-to-zirconia, precious-metal-acrylic-resin, non-precious-metal-acrylic resin, and PMMA). Again, implant survival rates were statistically significantly influenced by the applied restorative materials (p = 0.0126), whereas, no significant differences were reported regarding prosthetic survival rate.

CONCLUSIONS

Prosthetic material selection seems to have no clinically relevant influence on implant- and prosthetic survival rate in implant-supported fixed complete dentures. Due to the high chipping rate, quantifying prosthetic survival alone does not seem to be a reliable tool for evaluating the outcome of the restorations and providing recommendations. These results, along with the obvious lack of evidence, suggest that clinicians must exercise caution whenever porcelain-fused-to-zirconia or metal-resin restorations are considered.

Clinical performance of intentionally tilted implants versus axially positioned implants: A systematic review

OBJECTIVES

The aim of this review was to determine the clinical performance of dental implants that are intentionally tilted when compared with implants that are placed following the long axis of the residual alveolar ridge.

MATERIALS AND METHODS

A systematic review of the scientific literature using a predefined research question (PICO) and search strategy was undertaken. This search included five electronic databases. Two independent reviewers examined electronic databases and performed a manual review following search strategy to accomplish the item generation and reduction. Included articles were evaluated to determine the level of evidence. Data were extracted only from level I and level II studies, based on the Oxford Centre for Evidence-based Medicine-Levels of Evidence (March 2009). If included studies were homogeneous in nature, data were to be accumulated. However, if included studies were heterogeneous in nature, only descriptive data would be reviewed and analyzed.

RESULTS

A total of 811 articles were identified through the PICO question and search strategy. Detailed review of the abstracts and articles resulted in further item reduction, and 46 articles were included for full-text review. A total of 42 articles were then selected for inclusion in the systematic review. The identified articles included two level I and 20 level II studies. In addition, 15 level IV, one gray literature, and four previous systematic reviews with meta-analyses were also used in the study. The extracted data from the included studies demonstrated heterogeneity that prevented quantitative assessment, and only one level II study directly compared tilted and axially placed implants. Assessment of the descriptive data demonstrated no differences in implant survival, marginal bone loss, prosthesis survival, or patient-reported outcome measures (PROMs) whether implants are placed axially or with intentional inclination of the coronal aspect of the implant toward the distal aspect of edentulous jaws.

CONCLUSIONS

Based upon the systematic review of the literature, an analysis of the descriptive data suggested no differences in clinical performance between implants that are placed in an axial position relative to the residual alveolar ridge when compared with implants that are intentionally tilted toward the distal aspect of edentulous jaws.

Prosthetic Rehabilitation of Edentulous Patients With Implants Based on Facial Profile Assessment: A Case Report

PURPOSE

To introduce a user-friendly protocol for implant-retained prosthetic rehabilitation of fully edentulous patients based on facial profile and the cephalometric intermaxillary relationship.

MATERIALS AND METHODS

The prosthetic rehabilitation of edentulous patients with implants based on facial profile assessment protocol commences with a clinical and cephalometric analysis, followed by a preliminary projection to obtain a harmonious interarch relationship, eventually stabilized by the preplanned prosthesis. The protocol is divided into the following 5 phases: esthetic evaluation; cephalometric-occlusal assessment; surgery; provisionalization; and definitive prosthesis. Evaluation of patient's satisfaction from the treatment provided was performed through a preoperative and postoperative visual analogue scale scores.

RESULTS

The patient was granted immediate function and superior esthetics at day 1 of the treatment. These results were re-evaluated on an interval of 18 months and continued to be stable. The overall treatment time was significantly reduced.

CONCLUSION

Our recommended protocol gives the clinician a chance to grasp results beyond the offered by traditional protocols by using a wider perspective of rehabilitation, involving the patient's facial profile, thus fulfilling the integration of both occlusal and cephalometric parameters in a unified surgical-prosthetic approach.

Finite Element Stress Analysis of Applied Forces to Implants and Supporting Tissues Using the "All-on-Four" Concept with Different Occlusal Schemes

PURPOSE

The aim of this study was to evaluate stress distributions on implants and alveolar bone due to occlusal load produced during chewing by prostheses prepared according to the All-on-Four concept with different occlusal schemes using a finite element analysis method.

MATERIALS AND METHODS

On standard jaw models, teeth were set in accordance with the basic standards of canine-guided occlusion, group function occlusion, bilateral balanced occlusion (BBO), lingualized occlusion, and monoplane occlusion schemes. Three-dimensional (3D) images of these models were obtained using a surface scanner. Implants, superstructures, the maxilla, and mandible were modeled in the All-on-Four concept with 3D modeling software. Forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for all 5 occlusion types. Stress outputs were recorded as maximum and minimum principal stresses (P_max , P_min ) and von Mises stress values for the implants.

RESULTS

The highest P_max value for the maxilla was observed in cortical bone in the group function occlusion during lateral movement (15.56 MPa). For the mandible, the highest P_max value was observed on the cortical bone in maximum intercuspation of lingualized occlusion (72.75 MPa). The highest P_min value for the maxilla was observed during the lateral movement in group function and for the mandible in BBO (-29.23 and -86.31 MPa, respectively). The lowest stress values were observed with canine-guided occlusion in all related conditions and on all structures.

CONCLUSIONS

With the limitations of this simulation study, considering stresses on alveolar bone and implants in All-on-Four applications, the use of canine-guided occlusion may be suggested.

Effect of ultraviolet photofunctionalization of dental titanium implants on osseointegration

OBJECTIVE

The aim of the current study was to evaluate the effect of ultraviolet (UV) photofunctionalization of dental titanium implants with exposure to the oral cavity on osseointegration in an animal model.

METHODS

Forty-eight titanium implants (Camlog^® Conelog^® 4.3 mmx9.0 mm) were placed epicrestally into the edentulous jaws of three minipigs and implant stability was assessed by measuring the implant stability quotient (ISQ). Prior to implantation half of the implants were photofunctionalized with intense UV-light. After three months, the implants were exposed and ISQ was measured again. After six months of implant exposure, the minipigs were sacrificed and the harvested specimens were analyzed using histomorphometric, light, and fluorescence microscopy.

MAIN RESULTS

Forty-two of 48 implants osseointegrated. The overall mean bone-implant contact area (BIC) was (64±22)%. No significant differences were found in BIC or ISQ value (multivariate analysis of variance (MANOVA), P>0.05) between implants with and without exposure to UV photofunctionalization.

CONCLUSIONS

No significant effects were observed on osseointegration of dental titanium implants nine months after exposure of UV photofunctionalization.

Implant rehabilitation of the edentulous jaws: Does tilting of posterior implants at an angle greater than 45° affect bone resorption and implant success?: A retrospective study

PURPOSE

This study aimed to (1) investigate the success of posterior implants tilted >45° when 4 immediately loaded implants were used to support full-arch prostheses, eliminating any distal cantilever and (2) examine the effect on marginal bone loss (MBL) of different combinations of anterior multi-unit abutment (MUA) angles and posterior implant tilting angles.

MATERIALS AND METHODS

Records of patients rehabilitated according to the Columbus Bridge Protocol were analyzed. Peri-implant bone levels (PBLs) and MBL were measured for each implant. The influence of posterior implant tilting angle on PBL, MBL, and implant and prosthetic success rate was investigated. The impact on the same endpoints of different anterior MUA angles, and different combinations of anterior MUA and tilted posterior implant angles was also examined.

RESULTS

Records of 41 patients were analyzed, for a total of 46 complete rehabilitations, and 142 implants (52 anterior, 63 posterior tilted ≤45° [group 1], and 27 posterior tilted >45° [group 2]). No implants were lost during the follow-up (25.9 months), and no prosthetic complications were reported. Success rate for posterior implants was 100% in group 1 and 96.3% in group 2. Mean MBL differed significantly between the 2 groups (0.45 mm in group 1, 0.66 in group 2 [P = .04]), but not when the analysis was limited to implants in the same jaw. Implant tilting angle did not correlate with MBL and the MUA angle had no effect on bone resorption around posterior implants, neither in the sample as a whole nor in individual patients.

CONCLUSIONS

Posterior implants tilted >45° to eliminate distal cantilever may be as safe as those tilted less in severely atrophic jaws rehabilitated with immediately loaded, full-arch prostheses supported on 4 implants. Further prospective studies on larger samples of patients and implants and with longer follow-up are needed to confirm these findings.

Implant-Supported PMMA Monolithic Full-Arch Rehabilitation with Surgical Computer-Planned Guide and Immediate Provisional: A Case Report with One Year Follow-Up

The aim of this case report is to describe the surgical and prosthetic procedures to achieve maxillary and mandibular implant-supported PMMA monolithic full-arch rehabilitation (PMFR) with surgical computer-planned guide and immediate provisional. In such cases, the correct planning of dental implants' position, length, and diameter and the prosthetic phases via computer-aided design are very important to achieve good aesthetic and functional long-lasting results.

Immediate function dental implants inserted with less than 30N·cm of torque in full-arch maxillary rehabilitations using the All-on-4 concept: retrospective study

The aim of this retrospective clinical study was to evaluate the short-term implant success rate and marginal bone loss in full-arch fixed prosthetic maxillary rehabilitations supported by implants in immediate function with the All-on-4 treatment concept placed with insertion torque of <30N·cm or ≥30N·cm. This study included 83 patients (69 female, 14 male) with 332 implants placed (120 inserted with <30N·cm and 212 inserted with ≥30N·cm) who were treated between January 2010 and March 2013. Outcome measures were implant success and marginal bone loss at 1year of follow-up. Ten patients (12.0%; 13 implants inserted with <30N·cm and 27 implants with ≥30N·cm) were lost to follow-up. The cumulative implant success rate was 97.5% at the patient level, and 98.3% for implants inserted with <30N·cm and 97.5% for implants inserted with ≥30N·cm. The mean±standard deviation marginal bone loss at 1year was 1.14±0.38mm for implants inserted with <30N·cm and 1.39±0.49mm for implants inserted with ≥30N·cm (significant difference; P<0.001, Wilcoxon signed rank test). These results indicate that implants with insertion torques of <30N·cm may render comparable success rates and marginal bone loss at 1year compared to implants inserted with insertion torques of ≥30N·cm.

Double Guided Surgery in All-on-4® Concept: When Ostectomy Is Needed

Background

The rehabilitation of edentulous jaws with guided and flapless surgery applied to the All-on-4 concepts is a predictable treatment with a high implant and prosthetic survival rates, but there are several contraindications for this technique like when bone reduction is needed due to a high smile line in the maxilla or when there is an irregular or thin bone crest.

Purpose

To report a technique with double guided surgery for bone reduction and implant placement with the All-on-4 concept.

Materials and Methods

7 patients were included in the study. Guided implant planning was performed using CBCT, and the virtual templates were created with three dedicated software. Custom surgical templates were made for the ostectomy and for implants positioning.

Results

28 implants were placed using a double bone-supported surgical guide. The mean angular errors between the preoperative-planned implant and the postoperative-placed implant were 2.155° ± 2.03°; the mean distance errors between the planned and the placed implants were 0.763 mm ± 0.55 mm on the shoulder implant and 0.570 mm ± 0.40 mm on the apex implant.

Conclusions

The results of our study indicate that this treatment is predictable with an excellent survival rate allowing excellent results even when bone reduction is mandatory.

Bimaxillary simultaneous immediate loading of full-arch restorations: A case series

Aim

To describe a bimaxillary simultaneous immediate loading protocol with full-arch implant-supported fixed prostheses.

Material and Methods

A prospective case series of 8 patients who required full-arch rehabilitation was conducted. The main inclusion criteria were patients with teeth that required extraction. At least 1 molar per arch was temporarily employed to stabilize the surgical template and the provisional prosthesis during intraoral relining.

Results

Two upper implants failed in 1 patient. Structural fracture was registered in 3 patients, around 3 months after loading. All of them had bruxism. Three esthetic complications were registered: midline deviation, canting of the oclusal plane and color mismatch.

Conclusions

Although this protocol achieves optimal results, some mechanical complications were encountered. The fracture of the provisional prosthesis is a relatively common mechanical complication but does not seem to jeopardize the final treatment result.

Key words:Implant-supported full-arch, provisional prosthesis fracture, bimaxillary simultaneous rehabilitation, conical abutments.

The all-on-4 modified polyetheretherketone treatment approach: A clinical report

A modified polyetheretherketone (PEEK) implant framework material in combination with prefabricated high-impact poly(methyl methacrylate) (PMMA) veneers was used as an alternative material for the fabrication of a complete maxillary arch implant-supported fixed restoration. The elastic performance of the PEEK framework (elastic modulus of 4 GPa) combined with PMMA veneers may reduce the occlusal forces, protecting the implant-supported restoration and the opposing dentition, especially in all-on-4 treatments, where lack of proprioception and wide interimplant distance are present. Long-term clinical evidence is required before recommending the application as an alternative restorative material for such a prosthesis.

The Role of Occlusion in Implant Therapy: A Comprehensive Updated Review

PURPOSE

Occlusal overload may cause implant biomechanical failures, marginal bone loss, or even complete loss of osseointegration. Thus, it is important for clinicians to understand the role of occlusion in implant long-term stability. This systematic review updates the understanding of occlusion on dental implants, the impact on the surrounding peri-implant tissues, and the effects of occlusal overload on implants. Additionally, recommendations of occlusal scheme for implant prostheses and designs were formulated.

MATERIALS AND METHODS

Two reviewers completed a literature search using the PubMed database and a manual search of relevant journals. Relevant articles from January 1950 to September 20, 2015 published in the English language were considered.

RESULTS

Recommendations for implant occlusion are lacking in the literature. Despite this, implant occlusion should be carefully addressed.

CONCLUSION

Recommendations for occlusal schemes for single implants or fixed partial denture supported by implants include a mutually protected occlusion with anterior guidance and evenly distributed contacts with wide freedom in centric relation. Suggestions to reduce occlusal overload include reducing cantilevers, increasing the number of implants, increasing contact points, monitoring for parafunctional habits, narrowing the occlusal table, decreasing cuspal inclines, and using progressive loading in patients with poor bone quality. Protecting the implant and surrounding peri-implant bone requires an understanding of how occlusion plays a role in influencing long-term implant stability.

Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants

Background

Zygomatic implants are an alternative treatment in the rehabilitation of atrophic maxilla to promote stability in the stomatognathic system. The aim of this study was to compare the electromyographic (EMG) activity of masseter and temporalis muscles in controls and in individuals with complete implant-supported dentures anchored in the zygomatic bone.

Material and Methods

Fifty-four volunteers of both genders (mean age 52.5 years) were selected and distributed into two groups: Individuals with zygomatic implant (ZIG; n=27) and fully dentate patients (CG; n=27). MyoSystem-BR1 was used to assess masseter and temporalis muscles EMG activity in different mandibular movements: protrusion, clenching, maximal voluntary contraction (MVC) with Parafilm M®, right and left laterality and chewing (peanuts and raisins). Data was processed, normalized (MVC) and analyzed using the SPSS 21.0. Student t-test (P ≤ 0.05) was used for group comparison.

Results

The results were statistically significant (P ≤ 0.05) for protrusion, clenching, right and left laterality and raisin chewing. For the mandibular posture conditions, the ZIG obtained higher EMG activity patterns when compared to CG. For the masticatory performance during chewing of peanuts and raisins, the ZIG showed higher EMG mean values when compared to CG.

Conclusions

The zygomatic implant promoted an active response of the muscle fibers (hyperactivity) during both mandibular posture and chewing conditions, probably due to the absence of periodontal receptors, which play a significant role for preparing a bolus for swallowing.

Key words:Zygomatic implant, electromyography, masseter muscle, temporal muscle.

Immediate implant and rehabilitation based on All-on-4 concept in patients with generalized aggressive periodontitis: A medium-term prospective study

BACKGROUND

Aggressive periodontitis renders a great challenge to the conventional implant due to the risks of infection and ongoing marginal bone loss (MBL). A study about full-arch immediate implant and restoration in patients with advanced generalized aggressive periodontitis (GAP) was not read, even though the All-on-4 concept has been proven to be predictable for edentulous patients.

PURPOSE

This prospective study aimed to evaluate the feasibility and medium-term outcomes of immediate implant and rehabilitation based on the All-on-4 concept in patients with advanced GAP via clinical and radiographic analyses.

MATERIALS AND METHODS

Seventeen patients (mean age 39.4 years) with advanced GAP received immediate postextraction implant and rehabilitation based on the All-on-4 concept between January 2009 and January 2014. Eighty implants were inserted into 20 arches (7 maxillae and 13 mandibles). The average follow-up duration was 5 years (range 2-7). Complications, probing depth, and plaque, bleeding, and gingiva indices were evaluated. MBL was measured based on the panoramic radiographs taken immediately after surgery and annually thereafter.

RESULTS

The cumulative survival rate (CSR) of the implants was 98.75% (79/80) after an average of 5 years. One tilted implant failed due to peri-implantitis. The average peri-implant MBL was 0.8 ± 0.4 and 1.2 ± 0.3 mm after 1 and 7 years, respectively. The CSR was 100% (20/20) for definite prostheses, while 85% (17/20) for provisional prostheses. The average probing depth, and plaque, bleeding, and gingiva indices at the last recall visit were 3.0 ± 0.5, 1.2 ± 0.4, 0.5 ± 0.5, and 0.4 ± 0.4 mm, respectively. Patient showed high satisfaction to the overall effects.

CONCLUSIONS

Based on this study, the All-on-4 concept provided predictable outcomes in patients with GAP in 2- to 7-year follow-ups, and averted the severe bone defect area of aggressive periodontitis.

A comparative study on 7-year results of "All-on-Four™" immediate-function concept for completely edentulous mandibles: metal-ceramic vs. bar-retained superstructures

The study aims to document the clinical outcomes over a 7-year period of two techniques used for the rehabilitation of edentulous mandibles according to the "All-on-Four™" concept: (1) fixed complete-arch prostheses fabricated with metal-ceramic implant-supported fixed prosthesis with a titanium framework and all-ceramic crowns and (2) bar-retained implant-supported removable prosthesis with acrylic resin prosthetic teeth. The study was performed on 32 patients who received immediately loaded "All-on-Four™" fixed mandibular prostheses. (Fixed prostheses with ceramic superstructures, n:16; bar-retained removable acrylic prostheses, n:16). The patients were evaluated for up to 7 years after prosthesis completion. The endpoints included the evaluation of prosthodontic complications, bone resorption, plaque accumulation, bleeding on probing, periodontal probing depth and an oral health impact profile (OHIP). Bone loss remained under 1.2 mm in all of the implants, and no difference was observed between two groups. Plaque accumulation increased gradually in both groups, and the bar-retained acrylic-bearing implants showed significantly higher values during the first 5 years. Immediate improvement was assessed by the OHIP score in both groups. The observed bone loss and the subjective outcomes showed equivalent levels of clinical success for bar-retained and ceramic superstructures over a 7-year period. The higher level of plaque accumulation observed around implants with bar-retained superstructures requires that patients with acrylic superstructures be highly motivated to maintain their personal oral hygiene. Further studies are needed to clarify the occurrence of prosthodontic complications and assess their economic aspects.

The all-on-four treatment concept: Systematic review

Objectives

To systematically review the literature on the “all-on-four” treatment concept regarding its indications, surgical procedures, prosthetic protocols and technical and biological complications after at least three years in function.

Study Design

The three major electronic databases were screened: MEDLINE (via PubMed), EMBASE, and the Cochrane Library of the Cochrane Collaboration (CENTRAL). In addition, electronic screening was made of the ‘grey literature’ using the System for Information on Grey Literature in Europe - Open Grey, covering the period from January 2005 up to and including April 2016.

Results

A total of 728 articles were obtained from the initial screening process. Of these articles, 24 fulfilled the inclusion criteria. Methodological quality assessment showed sample size calculation to be reported by only one study, and follow-up did not include a large number of participants - a fact that may introduce bias and lead to misleading interpretations of the study results.

Conclusions

The all-on-four treatment concept offers a predictable way to treat the atrophic jaw in patients that do not prefer regenerative procedures, which increase morbidity and the treatment fees. The results obtained indicate a survival rate for more than 24 months of 99.8%. However, current evidence is limited due the scarcity of information referred to methodological quality, a lack of adequate follow-up, and sample attrition. Biological complications (e.g., peri-implantitis) are reported in few patients after a mean follow-up of two years. Adequate definition of the success / survival criteria is thus necessary, due the high prevalence of peri-implant diseases.

Key words:All-on-four, all-on-4, tilted implants, dental prostheses, immediate loading.

Terminal Posterior Tilted Implants Planned as a Sinus Graft Alternative for Fixed Full-Arch Implant-Supported Maxillary Restoration: A Case Series with 10- to 19-Year Results on 44 Consecutive Patients Presenting for Routine Maintenance

PURPOSE

Posterior maxillary tilted implants are gaining prevalence as an alternative to sinus grafts supporting fixed maxillary restorations. This paper reports long-term results after loading using this technique.

MATERIALS AND METHODS

Consecutive patients presenting for either routine hygiene maintenance or unplanned emergency care who had received tilted implants as a sinus graft alternative to support fixed fully implant-supported restoration of an edentulous maxilla and were followed for a minimum of 10 years from initial implant placement were included in this evaluation.

RESULTS

Forty-four patients were identified: 40 with bilateral tilted implants and 4 with one tilted and one axial posterior implant. Eight patients received one-piece fixed porcelain-to-gold screw-retained restorations, and thirty-six patients received a fully implant-supported patient-removable Marius Bridge. Seventy-nine out of 84 originally loaded posterior tilted implants survived a minimum of 10 years loading; one tilted implant was lost at 10 years. Eight additional posterior implants were placed for either these lost tilted posterior implants or as proactive supplemental support; one of these replacement tilted implants survived for at least 10 years and is included in the data. All patients have maintained continuous fixed function throughout the follow-up period. Forty-one out of 44 patients continue with the original restoration, 33 without modification or removal of the fixed restoration or implant-connecting bar. One porcelain-to-gold and seven Marius Bridges had framework modifications to accommodate additional implants; 3 Marius Bridge restorations were replaced with a newer generation.

CONCLUSION

Within the limits of this retrospective study, the results show that continuous fixed function of fully implant-supported maxillary restorations using posterior tilted implants in terminal positions of support as a sinus graft alternative combined with axial anterior implants is possible over a prolonged period. Loss of a posterior tilted implant after loading is treatable with another tilted, zygomatic or axial implant, typically requiring only modification of the fixed restoration.

Implant-Supported Immediately Loaded Fixed Full-Arch Dentures: Evaluation of Implant Survival Rates in a Case Cohort of up to 7 Years

BACKGROUND

The treatment of severely atrophied and edentulous jaws by means of fixed implant supported solutions is a challenging procedure.

PURPOSE

The immediate loading of four to six axial and tilted implants offers the possibility to overcome elaborate hard tissue augmentation procedures but lacks implant and patient related data on implant survival rates.

MATERIALS AND METHODS

This retrospective 7-years clinical trial investigated the implant survival rates of 2,081 implants (380 patients, 482 jaws) using an immediate loading protocol with either 4, 5, or 6 implants per restoration. Survival rates were calculated concerning implantation related factors (jaws/number of supporting implants/angulations/diameters/lengths) and patient related factors (medical status/smoking).

RESULTS

Overall survival of 2,081 implants was 97.0% on implant level. Survival rates of implantation related factors did not yield significant differences. Significant differences were yield between healthy patients and patients with osteoporosis (p = .002) and the medical status group "other" (p = .032), respectively. Smokers yielded a significantly higher survival than nonsmokers (p = .002).

CONCLUSIONS

It is assumed that four implants per jaw serve as a sufficient implant number for full arch restorations in both, the mandible and the maxilla. Osteoporosis under the medication with bisphosphonates seems to be a risk factor for implant survival. The authors suggest that the effect of smoking on ISRs remains controversial within this treatment concept.

Four-implant overdenture fully supported by a CAD-CAM titanium bar: A single-cohort prospective 1-year preliminary study

STATEMENT OF PROBLEM

In patients with an altered skeletal maxillomandibular relationship and bone resorption, the rehabilitation of edentulous jaws by combining 4 implants, 2 straight medially and 2 tilted distally, may be preferred to avoid a bone augmentation procedure.

PURPOSE

The purpose of this single cohort 1-year prospective study was to evaluate the clinical performance of a 4-implant overdenture fully supported by a computer-aided designed and computer-aided manufactured (CAD-CAM) titanium bar.

MATERIAL AND METHODS

This single cohort prospective study included edentulous participants rehabilitated with a 4-implant overdenture in 1 of the 2 jaws. The outcomes were implant and prosthetic survival and success rates, any biologic and technical complications, periimplant marginal bone loss, changes in the oral health impact profile (OHIP), bleeding on probing, and the plaque index.

RESULTS

Eighteen participants received 72 implants. One year after implant placement, no implants or prosthesis had failed, and no biologic or technical complications had been observed. At the 1-year follow-up, the mean marginal bone loss was 0.29 ±0.16 mm. The OHIP summary scores demonstrated a significant improvement in oral health-related quality of life. At the 1-year follow-up, positive bleeding was found in 2 participants (11.1%) around 3 implants (4.1%). Three participants (16.6%), accounting for 5 implants (6.9%), showed a slight amount of plaque.

CONCLUSIONS

A 4-implant overdenture supported by a CAD-CAM titanium bar may be a reliable option for the treatment of the edentulous mandible and maxilla over a 1-year period. Oral health-related quality of life significantly improved in all treated participants.

Two anterior wide-diameter implants using the All-on-4 concept in a predictable maxillary rehabilitation: A clinical report

The quality of maxillary bone is generally lower than that of mandibular bone; consequently, complete arch immediate implant-loading treatment is not as predictable in the maxillary as in the mandibular arch. The All-on-4 concept has proven to be an effective and successful treatment protocol. However, the survival rate of All-on-4 implants in the maxilla is lower than of those in the mandible. In this report, 2 anterior wide-diameter implants were used with the All-on-4 concept for a maxillary rehabilitation to provide biomechanical benefits with better primary stability while still achieving a functional and esthetic result. The clinical challenges of using wide-diameter implants in the anterior region are also discussed and should be considered during treatment planning.

An up to 7-Year Retrospective Analysis of Biologic and Technical Complication With the All-on-4 Concept

The aim of this study was to evaluate retrospectively biologic and technical complications as well as clinical and radiographic outcomes of patients treated with 4 implants according to the All-on-4 protocol and followed up to 7 years of function. Data from 56 consecutive patients presenting complete edentulous jaw, aged 18 years or older, treated between January 2008 and December 2013, were evaluated. The outcomes were implant and prosthetic survival and success rates, any complications, and marginal bone loss (MBL). Two-hundred twenty-four implants were placed in 56 patients. During the entire follow-up, 1 maxillary implant but no prosthesis failed during the healing process. Fourteen patients experienced 1 complication each (10 technical, 4 biologic). The overall implant and prosthetic success rate was 98.2% and 82.1%, respectively. All complications were considered as minor and successfully resolved chairside. A mean MBL of 1.30 ± 0.63 mm was observed at the last follow-up. Statistically significant difference was found for postextractive implants (0.79 ± 0.26) vs implants placed in healed sites (1.03 ± 0.46; P = 0.024). Within the limits of the present study, the All-on-4 concept may be a valuable surgical and prosthetic option for the treatment of complete edentulous jaws. However, minor technical and biologic complications can occur. Further long-term prospective data with primary outcomes focused on success rates are needed.

Five-Year Results of a Randomized Controlled Trial Comparing Patients Rehabilitated with Immediately Loaded Maxillary Cross-Arch Fixed Dental Prosthesis Supported by Four or Six Implants Placed Using Guided Surgery

PURPOSE

To compare the 5-year clinical and radiological outcomes of patients rehabilitated with four or six implants placed using guided surgery and immediate function concept.

MATERIALS AND METHODS

Forty patients randomly received four (All-on-4) or six (All-on-6) immediately loaded implants, placed using guided surgery, to support a cross-arch fixed dental prosthesis. Outcome measures were survival rates of implants and prostheses, complications, peri-implant marginal bone loss, and periodontal parameters.

RESULTS

No drop-out occurred. Seven implants failed at the 5-year follow-up examination: six in the All-on-6 group (5%) and one in the All-on-4 group (1.25%), with no statistically significant differences (p = .246). No prosthetic failure occurred. Both group experienced some technical and biologic complications with no statistically significant differences between groups (p = .501). All-on-4 treatment concept demonstrated a trend of more complications during the entire follow-up period. A trend of more implant failure was experienced for the All-on-6 treatment concept. Marginal bone loss (MBL) from baseline to the 5-year follow-up was not statistically different between All-on-4 (1.71 ± 0.42 mm) and All-on-6 (1.51 ± 0.36 mm) groups (p = .12). For periodontal parameters, there were no differences between groups (p > .05).

CONCLUSION

Both approaches may represent a predictable treatment option for the rehabilitation of complete edentulous patients in the medium term. Longer randomized controlled studies are needed to confirm these results.

Implant stability change and osseointegration speed of immediately loaded photofunctionalized implants

OBJECTIVES

This study evaluated the degree and rate of implant stability development for photofunctionalized dental implants in humans.

MATERIALS AND METHODS

Thirty-three implants (7 patients) placed in the maxilla and immediate loaded were evaluated. Photofunctionalization was performed by treating implants with ultraviolet for 15 minutes immediately before placement. Implant stability was assessed by measuring the implant stability quotient (ISQ) weekly starting from implant placement up to 3 months. Osseointegration speed index (OSI), defined as ISQ increase per month, was also evaluated.

RESULTS

The average ISQ for photofunctionalized implants at week 6 was 78.0, which was considerably higher than the average ISQ of 66.1, reported in literature for various as-received implants after a longer healing time of 2 to 6 months. No stability dip was observed for photofunctionalized implants regardless of the initial ISQ values. The OSI for photofunctionalized implants was 6.3 and 3.1 when their initial ISQ was 65 to 70 and 71 to 75, respectively, whereas the OSI values for as-received implants calculated from literature ranged from -3.0 to 1.17 with an average of -0.10.

CONCLUSIONS

Photofunctionalization accelerated and enhanced osseointegration of dental implants, providing novel and practical avenues for further advancement in implant therapy.

Simplified procedure for the immediate loading of a complete fixed prosthesis supported by four implants in the maxillary jaw: a 2-year prospective study

PURPOSE

The aim of this study was to verify the reliability of a system for the fixed retention of complete maxillary prostheses supported by four implants with a follow-up of 2 years.

MATERIAL AND METHODS

Patients were treated between September 2009 and December 2010 with four Straumann Bone Level SLActive implants supporting a complete prosthesis (CPs). The two distal implants were positioned mesially to the maxillary sinus and with a mesio-distal inclination ≤ 30° in order to reduce the distal prosthesis cantilever. An immediate loading surgical protocol was used. The CPs were planned to be fixed to multibase abutments to test their retention for a fixed rehabilitation. Clinical and radiographic parameters as probing pocket depth (PPD), bleeding score (mBI), plaque index (PI), and marginal bone loss (MBL) were assessed at a 1- and 2-year follow-up visits. Moreover, any biological and prosthodontic maintenance events were recorded. Clinical and radiographic parameters changes were analyzed.

RESULTS

Twenty-one patients treated with a total of 84 implants completed the 2-year examination period. Four patients were lost to follow up. No technical complication was recorded. Also, no implant, reconstruction, or abutment failures were observed. Therefore, an implant and prosthetic survival rate of 100% were achieved after 2 years. The mean periodontal parameter scores after 2 years of function were 2.6 mm for PPD (SD 0.8 mm), 0.3 for mBI (SD 0.5 mm), and 1.2 for PI (SD 0.4 mm) indexes, respectively. In addition, the mean MBL score measured at the 2-year follow-up visit was -0.34 mm (SD of -0.45 mm). Furthermore, no peri-implant soft tissue inflammation or peri-implant infection was observed.

CONCLUSIONS

It has been shown that immediate loading of four implants positioned anteriorly to the maxillary sinus could be a reliable treatment procedure to support fixed complete restorations.

Immediate loading short implants inserted on low bone quantity for the rehabilitation of the edentulous maxilla using an All-on-4 design

More studies evaluating the outcome of short-length dental implants in immediate loading are needed. To evaluate the use of short-length tapered implants in immediate loading for complete edentulous maxillae rehabilitations using an All-on-4 design. This retrospective clinical study included a cohort of 43 patients with 172 implants (74 short-length implants) inserted in low bone quantity. The patients were followed between 4 months and 6 years (average = 3 years). Outcome measures were implant survival, marginal bone remodelling, biological and mechanical complications. Two patients with four short-length implants were lost to follow-up during the first year. Three short and three long implants failed in four patients, rendering an overall cumulative survival rate implant and patient level, respectively, of 95.7% and 95.1% for short implants, 100% for regular implants and 96.6% and 95.2% for long implants. The average marginal bone remodelling at 1 and 3 years was 0.97 and 1.25 mm for the short implants, 0.82 and 0.87 mm for regular implants and 0.87 and 0.98 mm for long implants. Three patients presented 4 short-length implants with peri-implant pockets (3 implants in 2 patients were pseudo-pockets). Mechanical complications were registered in 13 patients (7 provisional prostheses fractures and 6 abutment screw loosening). All complications were treated successfully. Within the limitations of this clinical study, the short-term outcome of fixed prosthetic complete edentulous maxillae rehabilitations supported by short-length implants inserted in low bone quantity areas is viable. Long-term clinical studies are necessary for evaluating the outcome of these implants.

Posterior maxillary implants inserted with bicortical anchorage and placed in immediate function for partial or complete edentulous rehabilitations. A retrospective clinical study with a median follow-up of 7 years

PURPOSE

The aim of this study was to report the outcome of posterior maxillary implants inserted with "bicortical anchorage" in medium or low-density bone and placed in immediate function for the rehabilitation of patients with partial or complete edentulism.

METHODS

Eighty-eight patients (32 males and 56 females, mean age = 54 years; range 28-78 years) were included from October 1999 to November 2008, and followed between 6 months and 13 years (median of 7 years). A total of 124 posterior maxillary implants were inserted with bicortical anchorage (engaging the cortical plates of the maxillary crest along with that of either the sinus or nasal cavities) as follows: MkII (n = 1), MkIII (n = 6), MkIV (n = 18), and NobelSpeedy Groovy (n = 99); (Nobel Biocare AB). Implants were evaluated on the basis of survival, marginal bone levels, and complications (mechanical and biological).

RESULTS

Eleven patients dropped out of the study (12.5 %). Four implants were lost in four patients who underwent complete edentulous rehabilitations, yielding a cumulative survival rate of 94.2 % after a median follow-up of 7 years. The survival rate for the prostheses was 100 %. The marginal bone levels were on average 1.56 mm (standard deviation of 0.87 mm), after 5-years of follow-up. Biological complications occurred with 17 implants in 17 patients. Mechanical complications occurred in 49/88 patients. Thirty of these 49 patients were heavy bruxers.

CONCLUSIONS

Within the limitations of this study, fixed prosthetic rehabilitations for partial and complete edentulism supported by implants in the posterior maxilla which are inserted with bicortical anchorage and placed in immediate function is a viable concept on long-term follow-up. Nevertheless, controlling the occlusion is mandatory in order to decrease the likelihood of mechanical complications.

A systematic review and meta-analysis of removable and fixed implant-supported prostheses in edentulous jaws: post-loading implant loss

Objectives

The aim of this systematic review was to analyze post‐loading implant loss for implant‐supported prostheses in edentulous jaws, regarding a potential impact of implant location (maxilla vs. mandible), implant number per patient, type of prosthesis (removable vs. fixed), and type of attachment system (screw‐retained, ball vs. bar vs. telescopic crown).

Material and methods

A systematic literature search for randomized‐controlled trials (RCTs) or prospective studies was conducted within PubMed, Cochrane Library, and Embase. Quality assessment of the included studies was carried out, and the review was structured according to PRISMA. Implant loss and corresponding 3‐ and 5‐year survival rates were estimated by means of a Poisson regression model with total exposure time as offset.

Results

After title, abstract, and full‐text screening, 54 studies were included for qualitative analyses. Estimated 5‐year survival rates of implants were 97.9% [95% CI 97.4; 98.4] in the maxilla and 98.9% [95% CI 98.7; 99.1] in the mandible. Corresponding implant loss rates per 100 implant years were significantly higher in the maxilla (0.42 [95% CI 0.33; 0.53] vs. 0.22 [95% CI 0.17; 0.27]; P = 0.0001). Implant loss rates for fixed restorations were significantly lower compared to removable restorations (0.23 [95% CI 0.18; 0.29] vs. 0.35 [95% CI 0.28; 0.44]; P = 0.0148). Four implants and a fixed restoration in the mandible resulted in significantly higher implant loss rates compared to five or more implants with a fixed restoration. The analysis of one implant and a mandibular overdenture also revealed higher implant loss rates than an overdenture on two implants. The same (lower implant number = higher implant loss rate) applied when comparing 2 vs. 4 implants and a mandibular overdenture. Implant loss rates for maxillary overdentures on <4 implants were significantly higher than for four implants (7.22 [95% CI 5.41; 9.64] vs. 2.31 [1.56; 3.42]; P < 0.0001).

Conclusions

Implant location, type of restoration, and implant number do have an influence on the estimated implant loss rate. Consistent reporting of clinical studies is necessary and high‐quality studies are needed to confirm the present results.

Tilted versus axially placed dental implants: a meta-analysis

OBJECTIVES

The purpose of the present review was to test the null hypothesis of no difference in the implant failure rate, marginal bone loss, and postoperative infection for patients being rehabilitated by tilted or by axially placed dental implants, against the alternative hypothesis of a difference.

METHODS

An electronic search without time or language restrictions was undertaken in July 2014. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational. The estimates of an intervention were expressed in risk ratio (RR) and mean difference (MD) in millimetres.

RESULTS

The search strategy resulted in 44 publications. A total of 5029 dental implants were tilted (82 failures; 1.63%), and 5732 implants were axially placed (104 failures; 1.81%). The difference between the procedures did not significantly affect the implant failure rates (P=0.40), with a RR of 1.14 (95% CI 0.84-1.56). A statistically significant difference was found for implant failures when studies evaluating implants inserted in maxillae only were pooled (RR 1.70, 95% CI 1.05-2.74; P=0.03), the same not happening for the mandible (RR 0.77, 95% CI 0.39-1.52; P=0.45). There were no apparent significant effects of tilted dental implants on the occurrence of marginal bone loss (MD 0.03, 95% CI -0.03 to 0.08; P=0.32). Due to lack of satisfactory information, meta-analysis for the outcome 'postoperative infection' was not performed.

CONCLUSIONS

It is suggested that the differences in angulation of dental implants might not affect the implant survival or the marginal bone loss. The reliability and validity of the data collected and the potential for biases and confounding factors are some of the shortcomings of the present study.

CLINICAL SIGNIFICANCE

The question whether tilted implants are more at risk for failure than axially placed implants has received increasing attention in the last years. As the philosophies of treatment alter over time, a periodic review of the different concepts is necessary to refine techniques and eliminate unnecessary procedures. This would form a basis for optimum treatment.

Modified protocol of the intraoral welding technique for immediate implant-supported rehabilitation of the edentulous maxilla

PURPOSE

The aim of this study was to report the outcomes of a treatment option of immediate loading with intraoral welding on only 4 implants for the restoration of patients with maxillary edentulism.

MATERIALS AND METHODS

Seventeen consecutive patients were rehabilitated with 2 parallel and 2 tilted implants in the maxilla. Immediately after implant placement, angulated abutments were screwed on the implants to create better parallelism among the implants; thereafter, a titanium bar was intraorally welded to the welding pins to create a superstructure that rigidly splinted the implants. A fixed full-arch durable prosthesis was delivered on the same day of the surgery. The patients were followed for 26.5 months on average.

RESULTS

During the follow-up time, 2 implants were lost giving an implant survival rate of 97%. Nonetheless, all the prostheses remained in function and the prosthetic success was 100%.

CONCLUSIONS

The rehabilitation of the edentulous maxilla with an immediately loaded full-arch prosthesis, obtained through intraoral welding on only 4 implants, is a functionally and esthetically successful treatment.

10-year survival rate and the incidence of peri-implant disease of 374 titanium dental implants with a SLA surface: a prospective cohort study in 177 fully and partially edentulous patients

PURPOSE

This prospective cohort study evaluates the 10-year survival and incidence of peri-implant disease at implant and patient level of sandblasted, large grid, and acid-etched titanium dental implants (Straumann, soft tissue level, SLA surface) in fully and partially edentulous patients.

MATERIAL AND METHODS

Patients who had dental implant surgery in the period between November 1997 and June 2001, with a follow-up of at least 10 years, were investigated for clinical and radiological examination. Among the 506 inserted dental implants in 250 patients, 10-year data regarding the outcome of implants were available for 374 dental implants in 177 patients. In the current study, peri-implantitis was defined as advanced bone loss (≧1.5 mm. postloading) in combination with bleeding on probing.

RESULTS

At 10-year follow-up, only one implant was lost (0.3%) 2 months after implant surgery due to insufficient osseointegration. The average bone loss at 10 year postloading was 0.52 mm. Advanced bone loss at 10-year follow-up was present in 35 dental implants (9.8%). Seven percent of the observed dental implants showed bleeding on probing in combination with advanced bone loss and 4.2% when setting the threshold for advanced bone loss at 2.0 mm. Advanced bone loss without bleeding on probing was present in 2.8% of all implants.

CONCLUSION

In this prospective study, the 10-year survival rate at implant and patient level was 99.7% and 99.4%, respectively. Peri-implantitis was present in 7% of the observed dental implants according to the above-mentioned definition of peri-implantitis. This study shows that SLA implants offer predictable long-term results as support in the treatment of fully and partially edentulous patients.