Tilted implants in the immediate loading rehabilitation of the maxilla: a systematic review

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 full-arch fixed rehabilitation of a narrow mandible with newly conceived connection system implants: A case report

Rehabilitating thin jaws without reconstructive surgery entails using narrow implants. The proposed treatment adopted an innovative implant system, allowing the mini-screws to be parallel and immediately loaded. A mandible, wearing an overdenture, was functionalized contextually to the residual dental extraction and the placement of six 2.4-mm thick one-piece implants. Low-profile intermediate abutments, the LEMs, able to rotate over the spherical heads of the fixtures, were connected after suturing, oriented, and blocked in a mutual parallel position. The copings, engaging with a tapered juncture of the LEMs, resulted in their alignment to be intraorally wedged together. The provisional superstructure enclosed the copings and was immediately connected to the implants, and the definitive prosthesis was delivered after three months. No clinical signs of peri-implantitis or radiographically evident bone loss were recorded after a two-year follow-up without any prosthetic complication. No cases have been published regarding mini-implants bearing fixed prosthesis rehabilitation.

Immediate loading full-arch rehabilitation using transmucosal tissue-level implants with different variables associated: a one-year observational study

BACKGROUND

The aim of the present observational study was to investigate the application of transmucosal tissue-level implants in immediate loading full-arch rehabilitation with different variables associated.

METHODS

Patients needing a full-arch implant rehabilitation were recruited and rehabilitated with four transmucosal tissue level implants. Data related to implants' diameters and lengths, jaw distributions, and presence of angulated abutments were collected. The following outcomes were evaluated: survival rate, marginal bone loss (MBL), Plaque Index (PI), bleeding on probing (BoP), probing depth (PD). Descriptive statistical analysis was reported and univariate linear regression models were built to assess a significant correlation between MBL and the different implant related factors.

RESULTS

Twenty patients were rehabilitated for a total implant number of 80; 11 rehabilitations were performed on the maxilla, while 9 were performed on the mandible; 48 implants presented a 3.8 mm diameter and 32 implants presented a 4.25 mm diameter. Implants length varied between 10 to 15 mm; 40 tilted implants were connected to angulated abutment, while 40 straight implants were connected directly to the prostheses (no abutments). At the one year follow-up visit no implants failed resulting in an implant survival rate of 100%. The overall MBL was 1.19±0.30 mm. No statistically significant difference (P>0.05) was highlighted among any of the subgroups analyzed.

CONCLUSIONS

Despite different variables associated, tissue level implants seem to represent a valid option when applied in immediate loading full-arch rehabilitation. Further research and longer observational periods are encouraged to confirm the result.

Pterygoid and tuberosity implants in the atrophic posterior maxilla: A retrospective cohort study

STATEMENT OF PROBLEM

Rehabilitation of the partially or completely edentulous posterior maxilla using dental implants is a clinical challenge because of the presence of the maxillary sinus, as well as the low quality and quantity of bone in that region. In addition to bone augmentation procedures, posterior maxillary rehabilitation using implants includes their anchoring in bones such as the zygoma, pterygoid, and maxillary tuberosity, as well as in short implants. However, the performance of pterygoid and tuberosity implants in the atrophic posterior maxilla is unclear.

PURPOSE

The purpose of this retrospective cohort study was to evaluate the survival of tuberosity and pterygoid implants in patients with posterior maxillary atrophy.

MATERIAL AND METHODS

A nonprobability convenient sample of patients who had received fixed prostheses on implants placed in the maxillary tuberosity or pterygoid regions was analyzed retrospectively. Demographic variables included sex (male, female) and age. Implant-related variables included surface characteristics, site of placement, implant design, length, diameter, and anteroposterior insertion angle. Prosthetic-related variables included the type of reconstruction for rehabilitation and loading protocols. Implant survival, complications, crestal bone loss, and follow-up intervals were also documented. Collected data were analyzed at both patient and implant levels. The demographics and implant characteristics of patients receiving pterygoid or tuberosity implants were analyzed with a statistical software program (α=.05). Survival analysis was estimated by using the nonparametric Kaplan-Meier curve.

RESULTS

A total of 119 patients had 183 pterygoid or tuberosity implants inserted. Most implants in the pterygoid region (71.5%) were Ø4.1 mm (87.4%) and 15 mm in length (60.1%). The most common prostheses were complete maxillary reconstructions (49.2%) with late loading (74.3%). The average implant anteroposterior insertion angle was 60.8 degrees. The cumulative survival rate was 97.3% (n=178) during the mean follow-up period of 57 months (range 1 to 168 months). Among all implants placed, 2.7% failed (n=5) within 2 months of their placement. The statistically significant differences noted between tuberosity and pterygoid implants were related to design, surface characteristics, and loading. The average crestal bone loss was 1.5 mm.

CONCLUSIONS

The survival of the implants placed in the maxillary tuberosity and pterygoid regions was high in patients with posterior maxillary atrophy.

A Nonlinear Three-Dimensional Finite Element Analysis of Stress Distribution and Microstrain Evaluation in Short Dental Implants with Three Different Implant-Abutment Connections in Single and Splinted Conditions in the Posterior Mandible

Background

Stress distribution plays a vital role in the longevity and success of implant-supported prosthesis. This study evaluated the von Mises stress and microstrain in the peri-implant bone and the implant-abutment junction of short dental implants with three different implant-abutment connections in splinted and unsplinted conditions using finite element analysis (FEA).

Materials and Methods

In this experimental study, nine transversely isotropic finite element models were developed, and randomly divided into three equal groups (n = 3): control, (Group AC) single-standard 4.3 × 10 mm bone level implant-supported restorations with external hexagonal (EH) connection, internal conical (IC) and internal trichannel (ITC) connection, single short implant-supported restorations (Group AT), and splinted short implant-supported restorations (Group B) for each of the three implant-abutment connections, respectively. A 200 N load was applied along the long axis of the implants and a 100 N (45°) oblique load was applied and von Mises stress and microstrain values were evaluated.

Results

Single standard implants demonstrated the highest von Mises stress and microstrain values followed by single short implants and splinted short implants, respectively. Among the implant-abutment connections, the IC connection showed the highest values and the ITC connection showed the least values.

Conclusion

Within the limitations of this study, it was concluded that splinting of short dental implants demonstrated lesser and more homogeneous stress and microstrain, especially on oblique loading. The microstrain values for all connections evaluated were within the physiological loading limit (200-2,500 N) and were hence considered safe for clinical use.

Prevention of peri-implant disease in edentulous patients with fixed implant rehabilitations

OBJECTIVES

To provide an overview about the current approaches to prevent peri-implant diseases in edentulous patients with complete-arch implant-supported prostheses, and to review the clinical applications of the latest digital technologies for implant prosthodontics.

METHODS

A review of the guidelines to prevent peri-implant diseases in patient's receiving complete-arch implant-supported prostheses including facially driven treatment planning procedures using either conventional or digital methods, computer-aided implant planning procedures, and prosthodontic design variables including the optimal number and distribution of dental implants, implant to abutment connection type, implant or abutment level design, screw- or cement-retained alternatives, prostheses contours, and material selection is provided. Furthermore, an outline of the current therapeutic management approaches to address peri-implant diseases is reviewed.

CONCLUSIONS

Clinicians should understand and know different planning and design-related variables that can affect biological and mechanical complication rates of complete-arch implant-supported prostheses. Maintenance protocols are fundamental for minimizing biological and mechanical complications.

Managing the severely atrophic maxilla: Farewell to zygomatic implants and extensive augmentations?

BACKGROUND

Dental rehabilitation of severe atrophic upper jaws remains challenging. A new generation of subperiosteally placed and rigid multi-vector bone-anchored patient-specific implants proposes an innovative line extension in implant dentistry. This single-center retrospective study focused on treating severely atrophic maxillae using these implants.

METHODS

All patients who were treated with a patient-specific implant (IPS Implant® Preprosthetic, KLS-Martin, Tuttlingen, Germany) at Hannover Medical School due to severe atrophy of the maxilla who had no history of malignancy, cleft lip or palate, or trauma were evaluated regarding implant stability and prosthetic restoration, as well as complications.

RESULTS

Out of a total of 58 inserted implants, 13 implants in 10 patients, which were placed to treat a severely atrophic upper jaw, were identified. The mean follow-up period was 8.2 months (1-29 months). All implants were clinically stable over the entire period. All patients with an observation period of over 2 months received prosthetics for restoration. Minor complications, screw fractures, infection, and exposure of the framework were observed, but these did not lead to failure.

CONCLUSION

This initial follow-up suggests that this new generation of implants represents a valuable treatment alternative, especially for patients with a history of failed dental implant placement. Larger numbers of cases and longer observation periods are required to confirm our findings.

One-stage versus two-stage technique using two splinted extra-short implants: A multicentric split-mouth study with a one-year follow-up

OBJECTIVE

To compare the clinical outcomes of extra-short implants (≤6.5 mm) inserted with one-stage versus two-stage technique in adjacent sites of the upper or lower jaw.

MATERIALS AND METHODS

In this split-mouth multicenter study, implants were randomly divided into two groups according to the healing phase: two-stage and one-stage technique. Primary outcome measures were implant survival, implant success, and prosthodontic complications. Secondary outcome measurements were: implant stability quotient (ISQ) collected at surgery time (T0), and after 3 (T3) and 12 (T12) months, marginal bone level (MBL) evaluated at T0, T3, T6, and T12, marginal bone loss evaluated at T6 and T12, plaque index (PI), probing depth (PD), bleeding on probing (BoP) evaluated at T3, T6, and T12. Significances of differences between groups were tested by linear mixed model with random intercept.

RESULTS

Nineteen patients (8 males and 11 females) were included. A total of 38 implants were inserted. At T12 implant cumulative survival and implant success rate were 100% in both groups. No statistically significant differences were recorded for any of the analyzed parameters between the two groups at any time point. ISQ values were similar at T0 (two-stage: mean 67.53 ± SD 19.47; one-stage: mean 66.53 ± 19.07 p = 0.8738) and increased in both groups at the 12-month follow-up appointment (two-stage: 81.1 ± 7.04; one-stage: 81.39 ± 0.9266). MBL values were similar in the two groups at any time point. At T12 marginal bone loss was 0.46 ± 0.41 (two-stage) and 0.45 ± 0.38 (one-stage) mm (p = 0.9417), while mean PD was 2.7 ± 0.85 (two-stage) and 2.69 ± 0.89 (one-stage) mm.

CONCLUSIONS

Within the limits of the present short-term report, extra-short implants demonstrated optimal clinical outcomes using the one-stage technique, without statistically significant differences compared with the traditional two-stage approach.

Volumetric Evaluations of Full-Arch Implant Supported Restorations and Their Role on Patients’ Quality of Life: A Mixed-Model Analysis

Introduction

Full-arch, implant-supported hybrid restorations, employing tilted implants, can offer an efficient way of treating edentulous patients. Several factors, such as the timing of implant placement and the inclination of the fixture, can have a detrimental effect on their stability. This retrospective study is aimed at discerning the role played by those factors.

Materials and Methods

Patients treated with full-arch, implant supported restorations were selected for this study; cone-beam computed tomography (CBCT) images, taken 3 months and 3 years after delivery of the final restoration, as well as peri-implant values, were obtained and compared; bone loss was measured on four sites for each implant and then averaged. These patients were recalled, and the OHIP-5 questionnaire was administered.

Results

21 patients, with a mean age of 53 years, were included in the present analysis. 108 implants were placed, and 25 Toronto prostheses were delivered. According to a mixed-model analysis, tilted implants (0.51, p < 0.001) had a higher rate of bone loss, while implants placed in a healed ridge suffered less bone loss than immediate implants (-0.21, p < 0.001). Patient-level variables have a significant effect on this variable, as implants coming from the same subject share a similar risk of bone loss. The mean response to the self-administered OHIP-5 questionnaire was 1.53 ± 0.29; other variables did not have a statistically significant effect on this outcome. Discussion/Conclusions. The results of the present study show that Toronto bridges prostheses are an efficient procedure for treating edentulous patients, as their oral-related quality of life is reported as satisfactory even 7 years after delivery of the restoration. Tilted and immediate implants are more at risk of bone loss. Implants coming from the same subject share a similar risk of bone loss.

Influence of abutment angulation on implant failure in immediately placed and restored implants in the esthetic zone

Background: Tooth extraction socket in the aesthetic area is a major indication for immediate implant placement greatly improving patient satisfaction and preserving the alveolar ridge. However, the effect of non-axial force on the peri-implant bone with subsequent early implant failure remains unclear. Objective: Evaluate the prognosis of tilted implants immediately placed and restored with angled abutments in comparison to straight implants restored with straight abutments in the esthetic area (anterior or premolars) using computer-aided surgical guides. Material and methods: Badly decayed non-restorable teeth in the aesthetic zone (anterior or premolars) were extracted atraumatically. Immediately after guided implant insertion, the abutments were adjusted and placed according to the allocation group (0, 15, or 25-degree angle) then a temporary crown was performed out of occlusion in centric and eccentric relation. Early implant failure was assessed at three and six months. Results: There was no statistically significant difference between the two groups (P=0.305). Straight and angled abutment groups showed 6 (14.3%) and 8 (20%) failed cases, respectively. The post-hoc subgroup analysis showed no statistically significant difference between angle 15 and angle 25 degree groups where (P=0.686) or between Anterior and Premolar groups (P=0.853). Conclusion: There was no statistically significant difference in the failure rate when comparing angled to straight immediately placed & restored implants. This applies to both anterior and premolar implants.

Tilted Implants and Sinus Floor Elevation Techniques Compared in Posterior Edentulous Maxilla: A Retrospective Clinical Study over Four Years of Follow-Up

The aim of this study was to evaluate the implant survival rate, marginal bone loss, and surgical and prosthetic complications of implants placed through sinus floor elevation and tilted implants engaged in basal bone to bypass the maxillary sinus. Sixty patients were enrolled for this study. According to the residual bone height of the posterior maxilla, the sample was divided into three groups of 20 patients: Group A (lateral sinus floor elevation), Group B (transcrestal sinus floor elevation), and Group C (tilted implants employed to bypass the sinus floor). Follow-up visits were performed one week after surgery, at three and six months, and then once a year for the next 4 years. The outcomes were the implant survival rate, marginal bone loss, and surgical and prosthetic complications. Although Groups A, B, and C demonstrated implant survival rates of 83.3%, 86.7%, and 98.3%, respectively, the statistical analysis showed no statistically significant difference between groups. Statistically significant differences between groups were also not found concerning marginal bone loss, as recorded by intra-oral X-ray measurements during follow-up examinations. Regarding complications, it was not possible to perform a statistical analysis. To reduce possible surgical risks, implant placement in basal bone could be preferred.

Full-Arch Rehabilitation Using Trans-Mucosal Tissue-Level Implants with and without Implant-Abutment Units: A Case Report

Recently, tissue-level implants with a convergent collar have been introduced. While different studies have investigated the outcomes of this implant design in the rehabilitation of single teeth, its use in full-arch rehabilitation has yet to be investigated. The present case report describes the clinical outcomes of a full-arch immediate loading rehabilitation using tissue-level implants, with and without using implant-abutment units, with 2 years of follow-up. A female patient with mandibular terminal dentition and a high level of bone resorption (distal areas with a few millimeters of residual bone in the vertical dimension and both distal and anterior areas with narrow crestal bone in the horizontal dimension) was seen at the C.I.R Dental School, Turin, Italy. The patient was seeking to be rehabilitated with fixed prosthodontics, and she was found eligible for an immediate loading implant full-arch rehabilitation. Four implants were inserted in the same appointment. The two anterior implants were inserted straight and connected directly to the prosthesis (no abutments); the two distal implants were tilted in order to avoid the alveolar nerve and connected to two 30° angulated abutments. Two years post-implant placement, all of the implants were successfully integrated, resulting in an implant survival rate of 100%. The peri-implant soft tissues were stable at all the implant sites. No differences were highlighted between those implants with and without abutments. Within the limitations of the present clinical report, implant full-arch rehabilitations with tissue-level implants both with and without implant-abutment units showed optimal outcomes after two years of follow-up. Further research is encouraged to confirm whether this implant design may be a valid alternative to traditional implants in this type of rehabilitation, with or without implant-abutment units.

Rehabilitation of the Completely Edentulous Mandible by All-on-Four Treatment Concept: A Retrospective Cohort Study with Up to 10 Years Follow-Up

(1) Background and Objectives. Currently, there are no definitive long-term data about clinically significant difference in the failure of prosthesis and implant or marginal bone loss related to the rehabilitation of the completely edentulous mandible by all-on-four treatment concept. The main aim of present investigation was to report the long-term outcomes (10-years follow-up) of complete-arch mandibular rehabilitations based on the all-on-four concept. (2) Materials and Methods. Patients in need of extractions of teeth due to the occurrence of caries and/or severe periodontal disease and patients presented with edentulous mandibles were enrolled to the study. A total of 96 participants (mean follow-up period after intervention of 3185.2 days) were enrolled in the study. Participants were evaluated at the first visit, 10 days after intervention and every year after the intervention. Implant and prosthesis survival, bone loss and both local biological and mechanical complications were evaluated during the follow-up period. (3) Results. An implants’ survival rate of 97.9% was observed at the end of the follow-up period. Biological complications were reported in 19.8% of patients, whereas mechanical complications were reported in 27.1% of cases. The average marginal bone level at baseline was −0.03 mm. A significant marginal bone loss was observed after 10-years follow-up (2.5 mm). Binary logistic regression analysis showed significant association between smoke and both marginal bone loss and local biological complications. Lastly, a significant association was observed between bruxism and mechanical complications. (4) Conclusions. The high implant and prosthesis survival rate and the moderate incidence of biological and mechanical complications observed in present investigation can be associated to several factors such as high implant primary stability, prosthetic design, and control of the occlusal forces.

Radiographic and Histomorphometric Evaluation of Biomaterials Used for Lateral Sinus Augmentation: A Systematic Review on the Effect of Residual Bone Height and Vertical Graft Size on New Bone Formation and Graft Shrinkage

The aim of the present systematic review was to investigate the effect of residual bone height (RBH) and vertical bone gain on new bone formation (NBF) and graft shrinkage after lateral sinus lifts using different biomaterials.

METHODS

An electronic search was conducted on three databases to identify randomized controlled trials (RCTs) published until January 2021 with at least one follow-up at 6 months and at least five patients treated, comparing biomaterials used for maxillary sinus augmentation with a lateral approach. Graft volumetric changes, RBH, vertical bone gain, implant failure, and post-operative complications were evaluated. The risk of bias was assessed using the Cochrane tool.

RESULTS

We used 4010 identified studies, of which 21 were RCTs. Overall, 412 patients and 533 sinuses were evaluated. Only three publications had an overall low risk of bias. After 6 months, xenograft (XG) showed the least volume reduction (7.30 ± 15.49%), while autogenous graft (AU) was the most reabsorbed (41.71 ± 12.63%). NBF appeared to not be directly correlated with RBH; on the contrary, the overall linear regression analysis showed that NBF significantly decreased by 1.6% for each mm of postoperative vertical graft gain. This finding suggests that the greater the augmentation, the lower the NBF. A similar tendency, with a regression coefficient even higher than the overall one, was also observed with alloplast (AP) and XG.

CONCLUSIONS

The present results suggested that NBF was essentially independent of preoperative bone height. On the contrary, the smaller the volume was of the graft placed, the higher the amount of new bone formed, and the smaller the graft shrinkage was. Minimizing the augmentation volume might be beneficial to graft healing and stability especially when using AP and XG.

Clinical success between tilted and axial implants in edentulous maxilla: A systematic review and meta-analysis

Aim:

This systematic review and meta-analysis evaluated the clinical survival of axial and tilted implants in atrophic edentulous maxilla after three years of immediate loading and also the corresponding marginal bone loss.

Setting and Design:

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA).

Materials and Methods:

The relevant studies were retrieved from MEDLINE(PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), Science Direct, Google Scholar databases. The search was limited to studies published in the English language with no date restrictions. A further hand search was conducted on individual journals and reference lists of studies. The risk of bias in included studies was assessed by using the Evidence Project risk of bias tool.

Statistical Analysis Used:

Statistical meta-analysis was conducted using RevMan 5.4 software. The assessment for the level of evidence was done using GRADEpro software.

Results:

Eleven studies were finalised. All were included in the meta-analysis for implant survival, while only seven studies were included in the meta-analysis of marginal bone loss. After three years, the meta-analysis results for implant survival showed no statistical difference between axial and tilted implants, with the forest plot neither favouring axial nor tilted implants (RR = 1.00 (95% CI: 0.98-1.01); P-value = 0.59). After three years, the meta-analysis results for marginal bone showed no statistical difference between axial and tilted implants, with the forest plot neither favouring axial nor tilted implants (MD = -0.02; 95% CI; -0.09-0.06; P-value = 0.69).

Conclusion:

In the immediately loaded rehabilitation of completely edentulous atrophic maxillae, tilting of implants did not induce any significant alteration in their survival and their corresponding marginal bone loss levels compared to conventionally placed axial implants even after three years of function.

Tilted versus axial implant distribution in the posterior edentulous maxilla: A CBCT analysis

OBJECTIVES

This study aimed to determine whether distally angulating an implant is a successful strategy to avoid the maxillary sinus and the need for bone augmentation, while increasing the anterior-posterior (A-P) implant distribution in the edentulous maxilla.

MATERIALS AND METHODS

In 115 patients with edentulous maxillae, virtual implant planning was performed utilizing cone-beam computer tomographs. Axial (8 mm length) and tilted (12 mm length) dental implants with 30-degree and 45-degree angulation were virtually positioned to avoid entering the maxillary sinus, while maximizing A-P distribution. Measurements were made between the tilted and axial implants to assess the change in A-P distribution of implants at the implant and abutment levels.

RESULTS

Forty-seven sites (20.4%) were not able to have either treatment modality with insufficient bone for implant placement. Axial implants were placed more distally than 45-degree and 30-degree tilted implants in 24% and 42% of sites, respectively. The average change in A-P spread measured at the implant level, for 30- and 45-degree tilted implants was -0.25 mm (95% CI -0.76, 0.26) and 1.9 mm (95% CI 1.4, 2.3), respectively. When measured from the center of each multi-unit abutment the average increase in A-P distances for tilted implants appears larger in the 30-degree and 45-degree groups by 0.97 mm and 1.74 mm, respectively compared to measurements at the implant level.

CONCLUSIONS

Angulating 12 mm implants provides a limited increase in A-P distribution of implants in edentulous rehabilitation in most situations. In certain patients, the use of 8mm axial implants may provide a greater A-P spread.

Survival rates of axial and tilted implants in the rehabilitation of edentulous jaws using the All-on-four™ concept: A systematic review

Aim:

The aim of this review was to evaluate the survival rate of axial and tilted implants in rehabilitation of edentulous jaws using all on four concept.

Setting and Design:

Systematic Review.

Materials and Methods:

A literature review was performed in MEDLINE, PubMed Central (PMC), Google scholar, Embase, Cochrane Central Register of Controlled Trials. Hand searches were conducted of the bibliographic of related journals and systematic reviews. A total of 380 articles were obtained from the intial screening process. Of these articles, 25 articles fulfilled the inclusion criteria. The authors performed evaluation of articles independently as well as data extraction and quality assessment.

Statistical Analysis Used:

Qualitative analysis.

Results:

The major prosthetic complication was the fracture of the acrylic prosthesis. The mean cumulative survival rate of implants (72-132 months) were 94% to 98%. The prosthesis survival rate (12 months) was between 99% to 100%. The averaged bone loss was 1.3 ±0.4 mm (12-60 months). No Significant difference was found between survival rates of axial and tilted implants nor between maxilla and mandible.

Conclusion:

All on four concept can be employed successfully in the edentulous patients with resorbed ridges while improving their quality of life and reducing morbidity. However,randomized clinical trials with large sampling size and long term follow up should be incorporated.

Immediate rehabilitation of severely atrophic maxilla using trans-sinus nasal protocol and extended-length subcrestal angulated implants. Case series with one-year follow-up

<p>Immediate fixed full arch rehabilitation of the severely atrophic maxilla eliminates the use of a tissue supported prosthesis during the healing phase and maximises patient comfort and quality of life.<o:p></o:p></p> <p>The surgical treatment options available for immediate rehabilitation of the severely atrophic maxilla are dependent on the location and availability of the residual alveolar ridge. When bone is only available in the inter canine region, a graftless approach using tilted distal implants may not provide adequate distance between implants for favourable biomechanics. Subsequently, zygomatic implants are the alternative to provide adequate posterior occlusal support. &nbsp;<o:p></o:p></p> <p>The use of extended length sub crestal angulated implants offers an additional implant option for the clinician to restore the severely atrophic maxilla immediately. The treatment protocol involves anchorage of the implant fixture to the lateral wall of the nasal bone. The distally tilted implant transverses an augmented sinus cavity and extends to the site of the first permanent molar.&nbsp;The novel implant sub crestal angulation and use of a multi-unit abutment promotes passivity of fit of a full arch fixed immediate prosthesis.<o:p></o:p></p> <p>Five clinical case reports from private practice&nbsp;are presented which outline the clinical value of the novel implant design in the rehabilitation&nbsp;the severely&nbsp;atrophic maxilla. In each case, the use of zygomatic implants would&nbsp;conventionally have been prescribed due to the absence&nbsp;of residual alveolar bone in the maxilla&nbsp;premolar and molar regions. Alternatively,&nbsp;the use of extended length subcrestally angulated implants with straight of angulated multi-unit abutments have successfully restored the arch immediately.<o:p></o:p></p>.

Clinical performance of narrow-diameter titanium-zirconium implants in immediately loaded fixed full-arch prostheses: a 2-year clinical study

Objectives

The aim of this study was to evaluate the outcomes of immediate fixed full-arch prostheses supported by axial or tilted narrow-diameter Ti-Zr implants (3.3 mm) (Roxolid®, Institut Straumann® AG, Basel, Switzerland) (NDIs) in combination with standard-diameter implants up to 2 years’ follow-up.

Materials and methods

The study was conducted at Kocaeli University Faculty of Dentistry from 2016 to 2018. 37 jaws of 28 patients with an average age of 52 years were rehabilitated with fixed full-arch prostheses supported by 179 implants. Cumulative survival rate (CSR), implant success, marginal bone loss (MBL), and prosthetic survival rate as well as complications were analyzed.

Results

Total CSR of 99.4% and 98.5% for all and narrow implants respectively have been observed at 2 years’ follow-up. No prosthesis failures were observed, yielding a cumulative prosthetic survival rate of 100%. The NDIs achieved 0.63 mm MBL at 1 year and 1.02 mm at 2 years. The mean MBL at 1 year was 0.51 mm (mandible 0.63 mm/maxilla 0.41 mm) and 0.73 mm (mandible 0.90 mm/maxilla 0.43 mm) at 2 years. Both implant angulation and loading protocol did not influence the MBL.

Conclusions

The combination of narrow-diameter implants with standard-diameter implants in immediate fixed full-arch rehabilitation has a good prognosis to become a new standard of care for severely atrophic jaws.

Clinical relevance

The use of narrow-diameter implants in fixed full-arch rehabilitations in atrophic ridges would be a successful and predictable treatment approach.

Oral Health-Related Quality of Life and Full-Arch Immediate Loading Rehabilitation: An Evaluation of Preoperative, Intermediate, and Posttreatment Assessments of Patients Using a Modification of the OHIP Questionnaire

The aim of this study was to assess oral health-related quality of life (OHRQoL) of patients before, during, and after completion of implant-supported full-arch immediate loading rehabilitation according to the Columbus Bridge Protocol. Twenty-five patients with compromised dentition were rehabilitated according to the Columbus Bridge Protocol and were assessed for OHRQoL using 4 questionnaires specifically designed for this study and inspired by the Oral Health Impact Profile questionnaire. Patients assessed themselves before surgery, during the healing period (1 week and 2 months after surgery), and after definitive prosthodontic treatment (4 months after surgery). The questionnaires specifically investigated patients' pain, comfort, home oral hygiene habits, satisfaction related to esthetics, masticatory ability, phonetics and general satisfaction with the treatment. Patients reported an improvement of OHRQoL after full-arch immediate-loading rehabilitation. A statistically significant improvement in esthetics and chewing ability was found. After 4 months 92% of the patients did not feel tense about their smile, 96% did not indicate problems relating to other people or smiling, and 92% did not have difficulty eating some foods. Phonetics were a critical issue, especially in the intermediate phase of healing. One week after surgery, the percentage of patients who were very satisfied with phonetics slightly decreased from 48% to 36%. The assessment of patients' OHRQoL related to full-arch immediate-loading implant therapy exhibited a significant improvement in quality of life. The questionnaires herein presented could be an effective tool to evaluate patients' reaction to oral rehabilitation.

Evaluation of Crestal Bone Loss Around Straight and Tilted Implants in Patients Rehabilitated by Immediate-Loaded Full-Arch All-on-4 or All-on-6: A Prospective Study

The aim of this prospective study was to compare implant success rate and crestal bone loss around tilted and straight implants supporting immediate-loading full-arch rehabilitations. Twenty consecutive patients with edentulous jaws treated between June 2013 and July 2015 who satisfied all inclusion and exclusion criteria were included in the study. All patients were rehabilitated through a full-arch restoration supported by 4 or 6 immediately loaded implants. Clinical and radiographic examinations were scheduled every 12 months to evaluate implant success rates and crestal bone levels. Significant differences in crestal bone levels and success rates between straight and tilted implants were investigated by means of independent statistical analysis; differences were regarded as significant if P < .05. Seventy straight and 50 tilted implants were placed to rehabilitate 14 mandibles and 12 maxillae in 20 patients. After a follow-up of 12 to 36 months, survival rate was 97.1% for straight implants and 96.0% for tilted implants; while success rates were 94.3% and 94.0%, respectively. Success and survival rates were not significantly different (P > .05). Change in crestal bone level was 0.5 ± 0.4 mm for straight implants and 0.6 ± 0.4 mm for tilted implants (P > .05). Straight and tilted implants seemed to have similar behavior after immediate loading rehabilitations. After functional loading, straight and tilted implants did not differ significantly in clinical outcome.

Are There Alternatives to Invasive Site Development for Dental Implants? Part II

Despite improvements in bone preservation following tooth extraction, edentulous sites are often deficient in bone volume for conventional dental implant therapy. Missing bone volume is often recaptured by surgery and grafting. This article discusses noninvasive alternatives to bone grafting. Part I of this topic discussed the use of short and narrow diameter implants. Part II discusses three additional alternatives: the use of tilted implants, the use of four or fewer tilted and axially-loaded implants to support a full-arch fixed-dental-prosthesis (FAFDP), and the use of zygomatic implants to restore the severely-atrophic edentulous maxillae lacking adequate bone for conventional treatment.

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.

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.

Peri-Implant Behavior of Sloped Shoulder Dental Implants Used for All-On-Four Protocols: An Histomorphometric Analysis in Dogs

The aim of this study was to evaluate the soft tissue thickness and marginal bone loss around dental implants with sloped micro-threaded shoulder (30° angle) in comparing with conventional design, inserted 30° degrees angulated in post extraction sockets and immediate loaded with temporary prosthesis simulating the all-on-four protocol. Materials and Methods: Six fox hound dogs received forty-eight post extraction dental implants with the different diameter and length (Medentika, Germany), but with different neck configurations. Two group of implants were inserted 1mm subcrestal [corrected]. Control group has a micro-threaded neck and the Test group has a sloped microthreaded neck. Immediate loading was applied using a constructed metallic structure. After three months, soft and hard tissue levels were assessed by histomorphometric analysis. Results: The mean soft tissue thickness (STT) was 2.5 ± 0.2 mm for the Control group and 3.3 ± 0.3 mm for Test group (p = 0.036), meanwhile the mean marginal bone loss (MBL) was 1.53 ± 0.34 mm for Control group and, 1.62 ± 0.22 mm for Test group (p > 0.05). Conclusions: Within the limitations of this experimental model in dogs, the findings showed that dental implants with microthreaded and microthreaded sloped necks installed in immediate post extraction sites with immediate load, presented a comparable perimplant tissue behavior.

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.

Combination of straight and tilted implants for supporting screw-retained dental prostheses in atrophic posterior maxillae: A 2-year prospective study

OBJECTIVES

To evaluate the two-year survival rate (SR) and marginal bone loss (MBL) of fixed dental prostheses (FDPs) supported by straight (S) and tilted (T) implants under the influence of diverse study variables.

METHODS

A prospective investigation comprising 21 patients provided with a total of 27 maxillary screw-retained restorations fixed to 70 dental implants was developed. Two groups of implants were considered depending on their inclination with respect to the occlusal plane: Group 1 (S, n=37): straight/axial implants and Group 2 (T, n=33): tilted/angled fixations. Each FDP was supported by a combination of S and T implants. SR and MBL were assessed at the time of loading and two years after surgery. Patient-, surgical- and/or rehabilitation-related information was gathered. Data were statistically analysed at the α=0.05 significance level.

RESULTS

After 24 months, a 100% SR was achieved and the MBL of S and T implants were statistically similar. T implants located in the molar region showed lower MBL than did those replacing premolars (p=0.031).

CONCLUSIONS

Upright and angled fixations inserted at posterior maxillary areas resulted in comparable survival rates and peri-implant MBL after two years. The marginal bone resorption around tilted implants depended on their location.

CLINICAL SIGNIFICANCE

Screw-retained restorations fixed to straight and tilted implants seem to be a safe treatment option in posterior atrophic maxillae.

Carbon fibre versus metal framework in full-arch immediate loading rehabilitations of the maxilla - a cohort clinical study

Frameworks made of carbon fibre-reinforced composites (CFRC) seem to be a viable alternative to traditional metal frameworks in implant prosthodontics. CFRC provide stiffness, rigidity and optimal biocompatibility. The aim of the present prospective study was to compare carbon fibre frameworks versus metal frameworks used to rigidly splint implants in full-arch immediate loading rehabilitations. Forty-two patients (test group) were rehabilitated with full-arch immediate loading rehabilitations of the upper jaw (total: 170 implants) following the Columbus Bridge Protocol with four to six implants with distal tilted implants. All patients were treated with resin screw-retained full-arch prostheses endowed with carbon fibre frameworks. The mean follow-up was 22 months (range: 18-24). Differences in the absolute change of bone resorption over time between the two implant sides (mesial and distal) were assessed performing a Mann-Whitney U-test. The outcomes were statistically compared with those of patients rehabilitated following the same protocol but using metal frameworks (control group: 34 patients with 163 implants - data reported in Tealdo, Menini, Bevilacqua, Pera, Pesce, Signori, Pera, Int J Prosthodont, 27, 2014, 207). Ten implants failed in the control group (6·1%); none failed in the test group (P = 0·002). A statistically significant difference in the absolute change of bone resorption around the implants was found between the two groups (P = 0·004), with greater mean peri-implant bone resorption in the control group (1 mm) compared to the test group (0·8 mm). Carbon fibre frameworks may be considered as a viable alternative to the metal ones and showed less marginal bone loss around implants and a greater implant survival rate during the observation period.

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.

The all-on-four concept may be a viable treatment option for edentulous rehabilitation

Data sourcesMedline, the Cochrane Library, Google and hand-searches of systematic reviews and bibliographies from related journals in English and German up to August 2012.Study selectionThree reviewers independently searched for clinical trials that assessed the success rates of placing two anterior and two posterior tilted dental implants in humans either in the maxilla or mandible according to the all-on-four treatment concept. Inclusion limited studies with a minimum follow-up period of one year.Data extraction and synthesisThe primary outcome measure was the failure rate of implants. The secondary outcomes were prosthesis failure and marginal bone loss/bone level changes assessed through radiological examination. Failure rate was used to calculate standard deviations (SDs) of implants, whereas the mean success rate was used for dental implants and prostheses. Evaluation and quality assessment of articles and data extraction were performed by three independent reviewers. These reviewers estimated risk of bias by assessing the trial quality using a criteria form focused on the trial design, specification of inclusion/exclusion criteria, performance of surgery, outcome measure provided, radiographic examination of marginal bone level change as well as its evaluation and completeness of follow-up. Outcome measures were based on weighted means using a variance components analysis.ResultsThirteen studies, including 4,804 dental implants (2,000 maxilla and 2,804 mandible) placed in 1,201 jaws met the inclusion criteria. Nine were prospective trials, three retrospective studies and one longitudinal trial. All studies except one were considered to be at high risk of bias. Seventy-four (37 axially, 37 tilted) dental implants failed, with most failures (74%) within the first 12 months. Fifty-seven out of 1,201 prostheses failed but were repairable. The major prosthetic complication was the fracture of the all-acrylic prostheses. At 36 months the mean cumulative survival rates for implants and prostheses were 99.0 ± 1.0% (SD) and 99.9 ± 0.3% (SD), respectively with an average bone loss of 1.3 ± 0.4 mm (SD). There were no statistically significant differences in the clinical outcomes between maxillary versus mandibular arches and axially versus tilted placed implants.ConclusionsThe available evidence shows a promising short-term prognosis for the all-on-four treatment concept. However the evidence is limited by the quality of the available studies and the paucity of clinical trials of greater than five years.

Combining guided alveolar ridge reduction and guided implant placement for all-on-4 surgery: A clinical report

Immediate restoration with the all-on-4 concept has become an established treatment option. The technique involves alveoloplasty before implant placement to provide space for the prosthetic components and to provide a platform on which dental implants can be placed in clinical situations where a knife-edge alveolar ridge is present. Guided implant surgery involves the fabrication of a guide by using data from cone-beam computed tomography (CBCT) and implant surgery performed without flap reflection. In the presented technique, a printed cast based on a CBCT is used to fabricate a guide for both alveolar ridge reduction and guided implant surgery. The alveolar ridge reduction and implant surgery are virtually simulated in the laboratory to provide space for the restorative components and to avoid critical anatomic landmarks (mental nerve or perforation of the lingual mandibular plate). The described surgical guide enables guided alveolar ridge reduction and guided implant placement where the implant placement performed in the laboratory can be duplicated clinically during implant surgery.

Effects of pulsed electromagnetic fields on swelling and pain after implant surgery: a double-blind, randomized study

The aim of this split-mouth, double-blind, randomized study was to determine whether pulsed electromagnetic field therapy (PEMF) can improve swelling and the management of pain after full-arch immediate loading implant surgery. Eleven patients were selected for the study. Each patient received four distal tilted implants in the upper or lower jaw and underwent full-arch immediate loading rehabilitation. After surgery, two PEMF devices were applied to each patient, one on each cheek. In a random manner, one of these PEMF devices was switched on (test side); the other served as a placebo (control side). Forty-eight hours after surgery clinicians estimated postoperative swelling through photographic documentation, comparing the condition before and after surgery, while pain was assessed using a verbal rating scale. The patient's degree of comfort in relation to the PEMF devices was analyzed by questionnaire using a numerical rating scale. No statistically significant difference was observed between the test and control sides for swelling or pain (P>0.05). Most of the patients did not present swelling or pain at 48h after surgery, regardless of whether the PEMF device was activated or not. Various outcomes were found in the comfort evaluation. Within the limitations of this study, PEMF does not reduce postoperative swelling or pain after implant surgery.

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.

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.

Systematic review of short- (5-10 years) and long-term (10 years or more) survival and success of full-arch fixed dental hybrid prostheses and supporting implants

OBJECTIVES

The aim of this systematic review was to investigate the short-term (5-10 year mean follow-up) and long-term (10 year or more) survival and success of fixed full arch dental hybrid prosthesis and supporting dental implants.

METHODS

Studies reporting interventions with full-arch fixed dental hybrid prostheses were identified by searching PubMed/Medline (NCBI), Web of Science (Thomson Reuters), the Cochrane Register of Controlled Clinical Trials (EBSCO), and Dentistry and Oral Sciences Source (DOSS; EBSCO) from the earliest available dates through July 17, 2013. Through a series of review process by two examiners, potentially qualifying studies were identified and assessed with respect to the inclusion criteria.

RESULTS

A total of 18 studies were included for the quality assessment and the systematic review. Within the limitation of available studies, high short-term survival rates of full arch fixed dental hybrid prostheses (93.3-100%) and supporting implants (87.89-100%) were found. However, the availability of studies investigating long-term outcomes seemed scarce. Furthermore, the included studies were subjected to potential sources of bias (i.e. publication, reporting, attrition bias).

CONCLUSIONS

Despite seemingly high short-term survival, long-term survival of implant supported full arch fixed dental hybrid prosthesis could not be determined due to limited availability of true long-term studies. Although it may be a valuable option for a patient with a completely edentulous ridge(s), the strategic removal of teeth with satisfactory prognosis for the sake of delivering an implant supported full-arch dental hybrid prosthesis should be avoided.

Implant rehabilitation for atrophic maxilla: a review

A severely atrophied maxilla presents serious limitations for conventional implant placement. This presents challenge to the surgeon for implant placement in harmony with the planned prosthesis. Survey of various literatures using internet sources, manual searches, and common textbooks on dental implants shows, that a thorough knowledge of conventional augmentation procedures such as bone augmentation techniques, guided bone regeneration, alveolar distraction, maxillary sinus elevation techniques with or without grafting and contemporary techniques of implant placement provide effective long-term solutions in the management of the atrophic maxilla.

The expression of Fn14 via mechanical stress-activated JNK contributes to apoptosis induction in osteoblasts

Bone mass is maintained by the balance between the activities of bone-forming osteoblasts and bone-resorbing osteoclasts. It is well known that adequate mechanical stress is essential for the maintenance of bone mass, whereas excess mechanical stress induces bone resorption. However, it has not been clarified how osteoblasts respond to different magnitudes of mechanical stress. Here we report that large-magnitude (12%) cyclic stretch induced Ca(2+) influx, which activated reactive oxygen species generation in MC3T3-E1 osteoblasts. Reactive oxygen species then activated the ASK1-JNK/p38 pathways. The activated JNK led to transiently enhanced expression of FGF-inducible 14 (Fn14, a member of the TNF receptor superfamily) gene. Cells with enhanced expression of Fn14 subsequently acquired sensitivity to the ligand of Fn14, TNF-related weak inducer of apoptosis, and underwent apoptosis. On the other hand, the ASK1-p38 pathway induced expression of the monocyte chemoattractant protein 3 (MCP-3) gene, which promoted chemotaxis of preosteoclasts. In contrast, the ERK pathway was activated by small-magnitude stretching (1%) and induced expression of two osteogenic genes, collagen Ia (Col1a) and osteopontin (OPN). Moreover, activated JNK suppressed Col1a and OPN induction in large-magnitude mechanical stretch-loaded cells. The enhanced expression of Fn14 and MCP-3 by 12% stretch and the enhanced expression of Col1a and OPN by 1% stretch were also observed in mouse primary osteoblasts. These results suggest that differences in the response of osteoblasts to varying magnitudes of mechanical stress play a key role in switching the mode of bone metabolism between formation and resorption.

Immediate versus conventional loading of post-extraction implants in the edentulous jaws

PURPOSE

This retrospective study deals with the issue of how to realize the transition from a failing dentition to an implant-supported prosthesis. The main aim was to assess the reliability of immediate implant and immediate loading (IL) protocols in the edentulous jaws. A further aim was to investigate the role of patient-related, implant-related, and surgery-related secondary variables in the occurrence of implant failure.

MATERIALS AND METHODS

Patients with at least a 4-year post-loading follow-up undergoing the transition from a failing dentition to an implant-supported prosthesis were retrospectively investigated. Primary variables of implant failure were immediate placement and IL. Secondary variables were categorized as demographic, anatomic, site, and prosthetically related. Cumulative survival rates (CSRs) were compared using the Kaplan-Meier survival estimate method. Predictors of failure were included in a multivariate Cox regression model to evaluate the simultaneous effects of multiple covariates and control for correlated observation. Crestal bone loss was also measured at the delayed and the immediately loaded implants.

RESULTS

Five hundred nineteen implants rehabilitating 91 jaws in 80 patients were followed. The Kaplan-Meier survival estimate method showed that immediate implant and IL decreased the CSR significantly in the maxilla but not in the mandible. Some secondary variables were found to affect the CSR: maxillary location, age over 70 years, prostheses supported by only immediate implants or a majority of them, temporary cementation, implant diameter, and length. Crestal bone loss was not significantly related to the outcomes.

CONCLUSIONS

The present data may provide clinical recommendations to the practitioner treating the transitional patient. In the mandible, the use of immediate implants and IL does not increase the failure rate. In the maxilla however, combining immediate placement and IL may significantly increase the failure rate.