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A clinical study on the 6-year outcomes of immediately loaded three implants for completely edentulous mandibles: “the all-on-3 concept”
Abstract
The objective of the current study was to demonstrate the 6-year clinical and radiological treatment outcomes of the technique performed by immediately loading of three implants (single straight in the mid-line and two tilted distal implants) for the management of total edentulous mandibles and introduce a simple decision matrix for selection of the most appropriate protocol in cases with insufficient length of the interforaminal area. Re-assessments were performed over a total observation period of 6 years after surgery via measurement of bone resorption around implants, bleeding on probing, plaque accumulation, periodontal probing depth, bite force measurements and oral health impact profile. A total of 29 patients (45% women and 55% men) with a mean age of 65 ± 6 years enrolled in the study. 14 patients received an acryl-based bridge as definitive prosthetic restoration and 15 patients received a ceramic-based restoration. Both during the immediate loading phase and during the 6-year follow-up, there was no implantation loss. Regardless of the implant position, all implants showed continuous bone loss over the observation time. The bone loss around dental implants during observation period was only maximum 1.0 ± 1 mm and it remained well within the limits for ‘success’ according to the 2007 Pisa consensus (< 2 mm). The plaque index showed no significant fluctuations between the implant positions and the individual examination times. The approach described herein might help the surgeon by avoiding unnecessary loss of bone strength, selecting implant sites, and establishing the biomechanical advantage of increased A–P spread for immediate function.
... After further screening, 8 articles were excluded that did not meet the eligibility criteria. As a result, 16 articles were included in the final review published between 2001 and 2022 [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The results of the search strategy are outlined in the PRISMA flow diagram (Fig. 1). ...
... From the 16 articles identified for inclusion, two were randomised controlled trials [15,20], eight prospective cohort studies [10-13, 18, 19, 21, 25], five retrospective studies [14,16,17,23,24] and one was a case series [22]. Five studies were conducted in private practice [14,16,17,19,20], four within university dental departments [11,13,15,22], four in specialised implant institutes [18,21,23,24] and three multicentre studies [10,12,25]. ...
... From the 16 articles identified for inclusion, two were randomised controlled trials [15,20], eight prospective cohort studies [10-13, 18, 19, 21, 25], five retrospective studies [14,16,17,23,24] and one was a case series [22]. Five studies were conducted in private practice [14,16,17,19,20], four within university dental departments [11,13,15,22], four in specialised implant institutes [18,21,23,24] and three multicentre studies [10,12,25]. ...
Background:
Dental implants have been widely utilised as a treatment modality for prosthetic rehabilitation. The aim of this study was to evaluate the implant and prosthetic survival rate, changes in marginal bone level, and patient satisfaction outcomes with the use of three implants to support a fixed prosthesis in the edentulous mandible.
Methods:
A comprehensive electronic search was performed in the MEDLINE, Embase and Cochrane databases to retrieve studies that met the selection criteria. Sixteen articles were selected which consisted of two randomised controlled trials, eight prospective cohort studies, five retrospective studies and one case series.
Results:
A total of 2055 implants were placed in 685 patients with a mean age of 62.2 years. The mean cumulative implant survival rate was 96.2% over a mean follow-up period of 3.35 years. Mean marginal bone loss recorded was 1.25 mm and high patient satisfaction rates were reported across the studies.
Conclusion:
The use of three implants to support a fixed prosthesis appears to be a successful approach to restoring the edentulous mandible in the short-to-medium term. Further longitudinal comparative studies are required to support longer-term success, and to guide minimum implant dimension requirements for the technique.
... Information about the studies included for review and results (study type, sample size, implant survival rate, follow up, rehabilitation type, loading, implant survival rate, prosthetic survival rate, patient-reported outcomes, complications, and marginal bone loss) are shown in Tables 1 and 2. The 13 articles were all cohort studies, five retrospective and eight prospective. All patients attended follow-up periods of at least 1 year after dental implant placement and the maximum follow-up period was 6 years [22]. ...
... Out of a total of 728 patients, 2184 dental implants were placed to support 728 mandibular implantsupported screw-fixed prostheses (each supported by three implants). Nine studies placed the implants straight, three studies tilted posterior implants, and one study did not mention angulation [22]. ...
... Six studies mentioned the use of abutments [1,7,16,22,23,27]; nevertheless, only Hatano et al. [23] provided extra information about the abutment type (multiunit, minuscone or estheticone). Moreover, De Bruyn et al. [7] brought information about abutment height (varying between 3-5.5 mm). ...
This systematic review and meta-analysis set out to assess the clinical behavior of mandibular implant-supported fixed complete dental prostheses (ISFCDP) on three dental implants by analyzing implant and prosthetic survival rates, marginal bone loss, biological/technical complications, and
patient-reported outcomes. The review was conducted according to PRISMA guidelines. Electronic
searches were conducted in the Medline (PubMed), Web of Science, and Cochrane databases, complimented by a manual search in specialist journals for relevant articles published up to February 2021.
The Newcastle-Ottawa Quality Assessment Scale tool was used to assess the quality of evidence in
the studies reviewed. The study included 13 articles with 728 patients treated with 2184 implants.
A mean implant survival rate of 95.9% (95% CI: 94.6–97.3%) and a prosthetic survival rate of 97.0%
(95% CI: 95.7–98.3%) were obtained over 1–6-year follow-up periods. Mandibular implant-supported
fixed complete dental prostheses on three dental implants would appear to be a viable option for
restoring the edentulous mandible in comparison with mandibular ISFCDP on more than three
implants. Further comparative studies are needed, with adequate protocols, as well as sufficient
sample sizes and follow-up periods to confirm these findings.
Citation: Sánchez-Labrador, L.; Molinero-Mourelle, P.; Cortés-Bretón Brinkmann, J.; Prados-Frutos, J.C.; Gómez-Polo, M.; Martínez-González, J.M. Clinical Behavior and Complications of Mandibular Full-Arch Fixed Dental Prostheses Supported by Three Dental Implants. A Systematic Review and Meta-Analysis. Biology 2021, 10, 308.
... This method, which was realized with special parts of Branemark brand, formerly known as the Branemark Novum protocol, 7 was applied later without the use of special parts with the designs used in fixed prosthetic treatments on conventional implant. [8][9][10][11] The type of bar material used in treatments where fixed prosthetic treatment is performed with a small number of implants such as AOF and AOT can affect stress transfer. Elastic stresses in the bar may affect the stress from other prosthetic components and to the bone. ...
... Some researchers have inclined the posterior implants distally in the AOT concept. 8,9 The effects of such an application in stress distribution should be investigated. ...
... Only with three implants distributed triangularly, it is possible to improve stability and avoid rotation force. Therefore, the stability of a prosthesis retained by three implants can be classified as superior to that of a restoration with one or two implants [18]. However, up to date, no research has been able to prove that three implants retaining an overdenture is superior to one or two implants in a prospective clinical study, especially in terms of masticatory function and OHRQoL. ...
Purpose: The aim of this article is to evaluate to the masticatory function performance and Oral Health-related Quality of Life (OHRQoL) in implant-retained overdenture compared with different implant number placements in the edentulous mandible.
Methods: From 2013 to 2015, each patients received 3 implants (iSy-Implant, Camlog, Wimsheim, Germany) in intraforaminal mandible (34, 41/31, 44). After operation, inserted implants were gradually loaded and incorporated into an overdenture with a self-aligning attachment system (Locator abutments) in 3 + 3 + 3 months. Five checked points were performed chewing cycle test with multicolored chewing gum and OHIP-G14 questionnaire and a sum score questionnaire as following: preoperation, one implant load (41/31), two implants loaded (33,43), three implants loaded and 1-year follow up.
Result: A total of 10 patients with 30 implants were placed, the survival rate of the implants was 100% within 1-year follow-up. Regarding the masticatory function analysis, for the higher number of chewing cycles, the higher mixing rate was observed. After 1 year, the inter-mixing rate without significant changes was found compared to the time after three implants were loaded with attachment system. The mean value of OHIP-G14 was 30.4 preoperatively, 21.1 after loading the first locator, 10.7 after loading two locator abutments, and 3.2 after loading all three locator abutments. After 1 year, OHIP-G14 was 2.6 without significantly changed. The mean of the sum score was 15.5 preoperatively, 27.8 after activation of the first locator, 39.4 after activation of two locators, 46.2 after activation of all three locators, and 47.3 after 1 year. An increase of 0.7 sum score units per time point was observed. No significance was detectable, analogous to OHIP-G14, compared to the time of activation of all three locator setups (p-value = 0.22).
Conclusions: A significant improvement in masticatory function performance and OHRQoL was evaluated with the increasing number of implants with locator attachment in edentulous mandible. With the investigation of the OHIP-G14 and sum score, the results of patient report outcome might be associated with the increase in the number of implants.
... Implementing the widespread use of dental implants for the rehabilitation of fully edentulous arches has become relatively popular. Full arch rehabilitation can be accomplished with either a fixed or detachable overdenture prosthesis [1,2]. Implant-supported fixed restorations are an accepted treatment option for edentulous patients. ...
This clinical report explores the effectiveness of dental implants for rehabilitating fully edentulous arches, with a focus on the all-on-six treatment approach. Implant-supported fixed restorations, particularly using six implants, are presented as an expected and cost-effective solution for the rapid repair of the edentulous patient, avoiding the need for bone grafting. This report details the successful rehabilitation of a patient's completely edentulous arches using the all-on-six concept, highlighting the meticulous planning and execution involved. It concludes that precise diagnostic and implant planning, along with thorough attention to all the features, is crucial for successful implant-supported fixed prostheses, with the all-on-six concept offering improved clinical and radiological outcomes for atrophied maxillae.
... Stress values and distributions in the acrylic prosthesis against canine and molar forces EARLY ACCESS © ARIESDUE 2023; 15Oliva et al.(9), based on the All-on-4 concept, developed the All-on-3 concept with three implant placements in the lower and upper jaws, restored the implants with fixed prostheses, and reported a success rate of 100% at the end of a 5-year follow-up period. Ayna et al.(21) reported that, as a result of a 6-year follow-up of the All-on-3 concept, which they applied in 29 patients under the condition of immediate prosthetic loading, there was no implant loss and only a mean bone loss of 1.0 ±1.0 mm was experienced around the implants. This concept is evaluated in the ALL3 model in the present study. ...
Aim The study aims to compare the rehabilitation of the posterior atrophic edentulous mandible with different interforami-nal implant placement concepts to apply an implant-supported fixed prosthesis, without needing any bone grafting procedure. Material and methods Six models were created in a digital environment. Three, four, and five implants were vertically placed in different models; the Nobel Trefoil concept, the All-on-3, and the All-on-4 concepts were also simulated. In the Trefoil model, implants specific to this concept were used. In all models, the prosthetic emergence of posterior implants was simulated at the same point. Screw-retained fixed pros-theses were placed on the implants. A spherical foodstuff force was applied to imitate the chewing forces from the canine and molar regions. The three-dimensional finite element method analyzed the stresses on bones, implants, and pros-thetic structures. Results The most balanced stress distribution was seen in the Trefoil concept, while the worst stresses were observed in the All-on-3. The stress obtained in the models with four and five vertical implants was very close. Increasing the number of implants slightly affected stress, however, reducing the number to three, significantly increased the stress. Inclined placement of the same number of implants increased stresses on bone. Conclusions With its unique implants, the trefoil concept emerged as the optimal treatment option for fixed prosthetic restoration in the interforaminal area. The best option among the models with standard diameter implants is four vertical implants. Inclined placement of posterior implants did not reduce stresses. On the contrary, it increased stresses, unless the emergence profile was moved posteriorly or the implant lengths were increased.
... With the increasing use of dental implants, the planning of the rehabilitation of the completely edentulous mandible with implant-supported fixed prostheses has changed over time. From the studies using six or more implants for rehabilitating an edentulous mandible over time (22), studies reporting that the rehabilitation of the mandible with three implants yielded successful results reached (23)(24)(25). One of the most common techniques for fixed implant-supported rehabilitation of the edentulous mandible in recent years is the placement of 4 implants in different configurations. ...
Aim This study aims to evaluate the effects of ultra-short implants in the posterior region to eliminate the distal prosthetic cantilevers in interforaminal implant placement techniques on the stresses on the peri-implant bone, implants, and prosthetic structures. Method Six models were created in a digital environment. In the interforaminal region, 3 and 4 vertically placed implants and All-on-4 techniques are modeled. In addition, models in which 4 mm implants support these techniques, in the posterior region, to eliminate cantilever extensions are simulated. In all models, the prosthetic emergence of posterior implants was simulated at the same point. Screw-retained fixed prostheses were placed on the implants. A spherical foodstuff force was applied to imitate the chewing forces from the canine and molar regions. The three-dimensional finite element method analyzed the stresses on bones, implants and prosthetic structures. Results The effects of supporting interforaminal implant placement techniques with ultra-short implants on peri-implant bone stresses were limited. On the other hand, significant stress differences were observed in stresses on implants, multiunit abutments, and prosthetic framework, especially against molar region forces. Conclusion Supporting the cantilever extensions of interforaminal implants in the posterior region with ultra-short implants has been shown to have the potential to reduce technical complications on prosthetic structures significantly. Supporting interforaminal implant placement concepts with short implants in the posterior region could be a more risk-free approach, especially in extra-risky cases such as bruxism.
... 21 In the past few years, another prosthetic alternative to All-On-Four has emerged: the All-On-Three technique. [22][23][24][25] This type of rehabilitation, specifically of the mandible, is gaining ground because of its reduced invasiveness, safety, and predictable results in the short-medium term. 8,25,26 However, the connection system, the loading conditions, and the composition of the framework could play an important role in preventing or favoring mechanical complications such as fractures, deformation of the frameworks, chipping, and wear of the ceramic coating. ...
Objective The aim of this study was to investigate by finite element method analysis the behaviour of a three-implant mandible Toronto framework made by three different materials, with two abutment systems and two loading conditions.
Materials and Methods Three implants were virtually inserted in a mandible model in positions 3.6, 4.1, and 4.6. Three prosthetic framework bars with the same design and dimension (4.8 × 5.5 mm) were projected. The variables introduced in the computer model were the framework materials (glass fiber reinforced resin, Co-Cr, TiAl6V4), the abutment systems (Multi-Unit-Abutment [MUA]/OT-Bridge), and the loading conditions (500 N vertical load on all the framework area and 400 N on a 7-mm distal cantilever). The computer was programmed with physical properties of the materials as derived from the literature. Maximum tension and deformation values for each variable were registered at framework, screws, and abutment level and then compared.
Results Metal frameworks Cr-Co and TiAl6V4 resulted in lower deformation than glass fiber-reinforced resin frameworks while presenting higher tension values. The OT-Bridge exhibited lower maximum tension and deformation values than the MUA system. The first loading condition reached higher tension and deformation values than the second and it resulted in more uniformly distributed load on all the framework area, especially with the OT-Bridge system.
Conclusion More rigid materials and OT-Bridge system decrease the deformation on the prosthetic components. Tension stresses are more uniformly distributed with glass fiber-reinforced resin, in the OT-Bridge system and avoiding cantilever loading.
... 1,2 Moreover, primary stability has become a crucial factor in implant dentistry to meet patients' expectations that necessitates the use of early and/or immediate loading protocols, such as ''teeth in a day.'' 3,4 However, the restricted bone volume and/or poor bone quality at an implant recipient site could negatively influence the initial stability and jeopardize treatment success. ...
Straumann ® BLX is a novel implant system, which has been proclaimed to provide an ideal primary stability in all types of bone. In the current study, the primary stability of Straumann ® BLX implant systems with Straumann ® tapered effect (TE) implants have been comparatively assessed in bovine ribs by using a simultaneous sinus elevation and implant insertion model. In the study group, BLX (4.0 x 12 mm), TE (4.1 x 12 mm), BLX (4,5 x 12 mm) and TE (4.8 x 12 mm) were placed in each bony window, which resembles sinus maxillaris. As a control, BLX and TE implants with same sizes were inserted into the proximal diaphysis of the bovine ribs. A total of 40 implant insertions were performed. The stability was measured with resonance frequence analysis. In the study group, TE implants of 4.8 mm showed significantly higher values compared to 4.5 mm BLX implants (p=0.116). However, BLX implants of 4.0 mm in the control group showed higher stability compared to TE with 4.0 mm diameter. (p=0.014). The primary stability of BLX implants in the control group was significantly higher compared to the experimental group in both widths (p=0.018 for BLX 4.0 and p=0.002 for BLX 4.5 respectively). The use of TE design with wide diameter in simultaneous implant placement with sinus lift could present higher ISQ values and might be more appropriate option for implant recipient sites with poor bone volume and quality. However, the advantage of BLX design in standard implant insertion protocols could be precious.
... Sugiura et al. have suggested that the crestal cortical bone height could significantly affect the maximum extent of micromotion and peri-implant bone strain in the low-density cancellous bone under immediate loading [6]. Several studies have also clearly showed that improving primary stability via bi-cortical anchorage plays a great role in the success of immediate loading protocols such as All-on-4™ [12] and All-on-3 [13] and implant placements following sinus floor augmentation. However, 70% of all agerelated bone loss is cortical [14] and the lack of cortical bone especially in the posterior maxillae could pose a great challenge for the clinician [15], especially in elderly dental implant patients. ...
Background: The aim of the current study was to comparatively assess the primary stability of different Straumann® implant designs (BLX, Straumann Tapered Effect, Bone Level Tapered, and Standard Plus) via resonance frequency analysis by using an implant insertion model in freshly slaughtered bovine ribs with and without cortical bone. Tapered Effect (4.1 × 10 mm), Bone Level Tapered (4.1 × 10 mm), Standard Plus (4.1 × 10 mm), and BLX (4.0 × 10 mm) implants were inserted into the distal epiphysis on the longitudinal axis of the freshly slaughtered bovine ribs. As a control, implants with the same sizes were inserted into the proximal diaphysis. The stability of the implants was examined with resonance frequency analysis.
Results: BLX and Tapered Effect implants showed higher implant stability quotient values in both study and control groups. All implant systems showed a significant decrease of mechanical anchorage in the study group. BLX and Bone Level Tapered designs had a significantly lower loss of mechanical anchorage in the lack of cortical bone.
Conclusion: Both Tapered Effect and BLX designs could ensure sufficient initial stability; however, BLX implants could be an appropriate option in the lack of cortical bone and poor bone quality at the implant recipient site.
Clinical relevance: BLX is a novel implant system, which could be especially beneficial in the presence of spongious bone type at posterior maxillae.
A 67-year-old male patient reported to the department with a chief complaint of tooth mobility. The patient presented with a medical history of diabetes for which he was on medication, and he also reported a history of chronic periodontitis. After a thorough assessment of the patient, a proper treatment plan was designed, which included full-mouth rehabilitation, prior to which the patient was advised full-mouth extraction. Six implants were inserted into the mandibular and maxillary arches as part of the treatment. After the implant was placed, zirconia was the preferred choice for the restoration because of its superior aesthetic results. Polyvinyl siloxane impression material was used to make implant impressions after an eight-week healing period. The case report provides the technique for the current approach to full-mouth rehabilitation with all six concepts of implant placement. In these situations, it is crucial to plan and insert implants correctly and adhere to the entire treatment plan. Restorations were performed using the latest computer-aided design/computer-aided manufacturing (CAD/CAM) technologies for a more aesthetically pleasing result. The case study highlights the significance of meticulous preparation and implementation for the accomplishment of successful full-mouth rehabilitation.
Purpose This study aims to compare five implant-supported rehabilitation concepts of an edentulous mandible and determines the most biomechanically advantageous technique. Materials and methods Five models with implants in different configurations were created: All-on-4 concept (two anterior axial and two posterior distally curved implants), All-on-4v4 concept (four distal curved interforaminal implants), All-on-4W (two anterior mesial curved interforaminal implants and two posterior distally curved implants), the All-on-3 concept (one anterior axial and two posterior distally curved implants), and the treofil system (three interforaminal implants with titanium bar guide support). For this study, bone-level (4.3 × 13 mm) implants of Nobel Biocare and implants of the treofil system (5 × 13 mm) were used. Spherical loads were applied from the canine and molar regions to evaluate the tension, compression and von Mises stresses by applying 3D finite element analysis. Results Among the alternative concepts, treofil system were the most successful treatment option in biomechanical terms. On the other hand, All-on-3 concept was found to be the last method of choice. This was because of the high stresses on cortical and trabecular bones in most conditions. Conclusion The result of this study shows that the treophylline system is the most successful treatment option despite its technical details. Alternatively, classical All-on-4 and All-on-4v4 techniques are biomechanically successful treatment options.
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.
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.
Objective:
There is no definitive study comparing stress distribution around two versus three implants in implant-retained overdentures with different cantilever length. The purpose of this finite element study was to evaluate stress pattern around the implants of the 2 or 3 implant- supported mandibular overdenture with different cantilevered length.
Materials and Methods:
The models used in this study were 2 and 3 implant-supported overdenture with bar and clip attachment system on an edentulous mandibular arch. Each model was modified according to cantilever length (0 mm, 7 mm, and 13 mm); thus, 6 models were obtained. The vertical load of 15 and 30 pounds were applied unilaterally to the first molar and 15 pounds to the first premolar, and the stress in bone was analyzed.
Results:
With increasing cantilever length, no similar stress pattern changes were observed in different areas, but in most instances, an increase in cantilever length did not increase the stress around the implant adjacent to cantilever.
Conclusions:
Within the limitations of this study, it can be concluded that increasing of cantilever length in mandibular overdentures retained by 2–3 implants did not cause distinct increasing in stress, especially around the implant adjacent to cantilever, it may be helpful to use cantilever in cases of mandibular overdenture supported by splinted implants with insufficient retention and stability. Based on the findings of this study, optimal cantilever length in mandibular overdenture cannot be determined.
The clinical success and longevity of endosteal dental implants as load bearing abutments are controlled largely by the mechanical
setting in which they function. The treatment plan is responsible for the design, number and position of the implants. In biomechanically
compromised environment such as poor quality bone, strain to the crestal bone can be reduced by increasing the anterioposterior
spread of implants, placement of longer implants and maximizing the number of implants. The All-on-4® concept is one such treatment
procedure which enlightens us for its use in the completely edentulous patients and which also leaves behind the routine treatment
alternative of conventional dentures with successful outcome in the short term, long term and the retrospective studies that have been
done in the past. The area of concern for any treatment alternative lies in the success of the prosthesis and its prosthodontic perspective
involving the principles of occlusion. This article reviews the All-on-4® concept and its prosthodontic aspects.
Abstract The objective of the present study is the evaluation of the comprehensive 5-year results of fixed mandibular dentures fabricated from metal-acrylic or metal-ceramics according to the 'All-on-4'™ protocol. Twenty-seven patients that received immediately loaded 'All-on-4'™ fixed mandibular dentures in 2005 were included in the study, and they were evaluated up to 5 years after denture integration. Endpoints were chosen in accordance with the 2007 Pisa consensus and included bone resorption, the Oral Health Impact Profile (OHIP), the Sulcus Fluid Flow Rate (SFFR), and prosthodontic complications. The initial situation in both groups was largely identical. Bone loss remained under 2 mm after 5 years in all implants and showed no group difference. The SSFR showed a gradual increase in both groups, and acrylic-bearing implants showed a substantially and significantly higher flow rate from the third year onward. The subjective improvement as expressed by the OHIP score was immediate and dramatic, and it showed no group differences. All acrylic restorations showed some extent of abrasion, and veneer fractures occurred in 4 patients (28.6%). Besides a single fracture of a fixation screw, there were no prosthetic complications in patients with ceramic suprastructures. According to bone loss and subjective outcome, acrylic and ceramic suprastructures apperared to be equivalent after 5 years; however, sulcus flow and prosthodontic complications suggest that the economic advantage of acrylic dentures may be specious. The rational choice of implant suprastructures requires comprehensive, long-term observation. Short-term economical benefits might be cancelled out in the long run.
Using the three-dimensional finite element method (FEM), this study compared the biomechanical behavior of the "All-on-Four" system with that of a six-implant-supported maxillary prosthesis with tilted distal implants. The von Mises stresses induced on the implants under different loading simulations were localized and quantified.
Three-dimensional models representing maxillae restored with an "All-on-Four" and with a six-implant-supported prosthesis were developed in three-dimensional design software and then transferred into FEM software. The models were subjected to four different loading simulations (full mouth biting, canine disclusion, load on a cantilever, load in the absence of a cantilever). The maximum von Mises stresses were localized and quantified for comparison.
In both models, in all loading simulations, the peak stress points were always located on the neck of the distal tilted implant. The von Mises stress values were higher in the "All-on-Four" model (7% to 29%, higher, depending on the simulation). In the presence of a cantilever, the maximum von Mises stress values increased by about 100% in both models.
The stress locations and distribution patterns were similar in the two models. The addition of implants resulted in a reduction of the maximum von Mises stress values. The cantilever greatly increased the stress.
Rehabilitation of atrophied edentulous arches with endosseous implants in the posterior regions is often associated with anatomic problems such as jaw shape and location of the mental loop, mandibular canal, and maxillary sinuses. The purpose of this investigation was to modify the method for implant placement in the posterior part of the jaws to extend fixed implant-connected prostheses further distally, and to reduce the length of cantilevers in complete-arch prostheses without transpositioning the mandibular nerve or performing bone grafting in the maxilla. Forty-seven consecutive patients were treated with implants (25 patients/36 mandibular implants, 22 patients/30 maxillary implants) placed in tilted positions. They were followed a mean of 40 months (mandibles) and 53 months (maxillae). In the mandible, implants close to the mental foramina were tilted posteriorly approximately 25 to 35 degrees. In the maxilla, the posterior implants were placed close to and parallel with the sinus walls and were titled anteriorly/posteriorly approximately 30 to 35 degrees. Patients gained a mean distance of 6.5 mm of prosthesis support in the mandible and 9.3 mm in the maxilla, as a result of implant tilting. There were no implant failures in mandibles. The cumulative success rates in the maxilla at 5 years were 98% for tilted implants and 93% for non-tilted implants. Paresthesias of the mental nerve were observed on 4 sides during the first 2 to 3 weeks after implant placement. Analysis of the load distribution in one mandibular case showed no significant difference between tilted and the non-tilted implants, and the improved prosthesis support was confirmed. Satisfactory medium-term results concerning osseointegration and significant extension of prosthesis support show that the method can be recommended. This technique may allow for longer implants to be placed with improved bone anchorage.
The primary function of a dental implant is to act as an abutment for a prosthetic device, similar to a natural tooth root and crown. Any success criteria, therefore, must include first and foremost support of a functional prosthesis. In addition, although clinical criteria for prosthetic success are beyond the scope of this article, patient satisfaction with the esthetic appearance of the implant restoration is necessary in clinical practice. The restoring dentist designs and fabricates a prosthesis similar to one supported by a tooth, and as such often evaluates and treats the dental implant similarly to a natural tooth. Yet, fundamental differences in the support system between these entities should be recognized. The purpose of this article is to use a few indices developed for natural teeth as an index that is specific for endosteal root-form implants. This article is also intended to update and upgrade what is purported to be implant success, implant survival, and implant failure. The Health Scale presented in this article was developed and accepted by the International Congress of Oral Implantologists Consensus Conference for Implant Success in Pisa, Italy, October 2007.
The aim of this paper was to demonstrate the treatment outcomes following immediate functional loading concept of short implants inserted for single tooth replacement in the posterior maxilla. The study was performed on 63 patients who received short (6 mm) implants for single tooth replacement in the posterior maxilla. Forty-eight patients underwent immediate functional concept, whereas 15 of the implants were loaded 3 months after insertion. The patients were evaluated for up to 5 years after prosthesis completion. The endpoints included the evaluation of implant survival rate, crown length, bone resorption, plaque accumulation (PI), bleeding on probing (BOP), periodontal probing depth (PPD) and assessment of oral health impact profile (OHIP). At the end of the follow-up period of 5 years, three implants (6.3%) from the immediate loading group have failed during the observation period. Bone loss was significantly lower in the delayed loading group compared to the immediately loaded implants. At the end of the second year, BOP values were higher in the immediately loaded group. Throughout the observation period, PI values in the group with immediate loading were higher. PPD increased consistently and during the first 3 years in the immediate loading group. As a conclusion, short implants inserted for single tooth replacement at the posterior maxilla presented with satisfactory clinical outcomes in both immediate and delayed loading concepts. However, immediately loaded implants presented with an increased bone loss and higher BOP values. As assessed by the OHIP score, a subjective improvement was observed in both groups without significant differences.
Purpose:
To evaluate and compare the clinical and radiographic outcomes of mandibular rehabilitation with fixed prostheses on three implants with immediate versus delayed loading.
Materials and methods:
The sample comprised 21 patients who underwent treatment with immediate loading and 23 who received delayed loading. All had worn their prostheses for at least 18 months. Radiographic evaluation of bone loss was carried out in Adobe Photoshop CS5 by a single calibrated examiner using digitized panoramic radiographs. Clinical examination of the technical conditions of the prosthetic device assessed the condition of the acrylic resin base, dental occlusion, metal framework, presence of cover screws, screw fixation of the prosthesis and abutments, length of cantilever (effort) and resistance arms, presence of plaque on prosthetic abutments, and hygiene of the prosthesis.
Results:
One implant failed in each group, resulting in a 95.23% treatment success rate with immediate loading and 95.65% with delayed loading (no statistically significant between-group difference). In the immediate-loading group, the mean bone loss was 1.96 ± 0.73 mm around central implants and 1.64 ± 0.84 mm at distal implants. In the delayed-loading group, the mean bone loss was 1.85 ± 0.67 mm around central implants and 1.70 ± 0.77 mm at distal implants. According to Student t test, there was no significant within-group difference in bone loss and no difference between the immediate-loading and delayed-loading groups. The only prosthesis-related complications that differed significantly between groups were "condition of the acrylic base," "occlusion," and "presence of right cover screw." There was no statistically significant association of lever arm ratio with peri-implant bone loss or bone loss on the mesial surfaces compared to the distal surfaces of the distal implants.
Conclusion:
The three-implant-supported fixed prosthesis protocol tested in this study proved to be a viable therapeutic strategy for mandibular edentulous patients with maxillary complete dentures, regardless of whether loading was immediate or delayed, with no difference in peri-implant bone loss.
Purpose:
The aim of this study was to compare masticatory performance, occlusal force, and oral health-related quality of life (OHRQoL) in patients with mandibular distal-extension edentulism between those with implant-supported fixed prostheses (ISFPs) and those with removable partial dentures (RPDs), and to evaluate relationships among them.
Materials and methods:
Subjects were recruited from patients using ISFPs or RPDs for mandibular distal-extension edentulism. Masticatory performance was evaluated based on the glucose extracted from chewed gummy jelly. Occlusal force was measured with a pressure-sensitive sheet, and data were subjected to computer analysis. The Japanese version of the Oral Health Impact Profile (OHIP-J) was used to evaluate OHRQoL. The masticatory performance, occlusal force, and OHIP-J scores of the ISFP and RPD groups were compared using the Wilcoxon rank-sum test. The relationships among the variables were analyzed using the Spearman rank correlation coefficient test. Multivariate logistic regression analysis was employed with the OHIP-J score as a dependent variable.
Results:
Nineteen patients with ISFPs and 25 patients with RPDs participated in this study. No significant difference was observed between the two groups with regard to masticatory performance and occlusal force. The OHIP-J score was significantly lower in the ISFP group than in the RPD group. The OHIP-J score had no significant correlation with masticatory performance, but was significantly correlated with occlusal force and the prosthetic method. Multivariate logistic regression analysis showed that younger age, RPDs, and lower occlusal force were significantly associated with a higher OHIP-J summary score.
Conclusion:
The present results suggest that the difference in masticatory performance and occlusal force between ISFPs and RPDs is small, but ISFPs are superior to RPDs with regard to OHRQoL in patients with mandibular distal-extension edentulism. In addition, there appears to be a slight correlation between the OHIP-J and occlusal force in these patients.
Background:
There is a necessity of studies documenting the long-term outcome of full-arch flapless rehabilitations.
Purpose:
To evaluate the 7 years implant and prosthesis survival rate and 5-years marginal bone loss of full-arch fixed prosthetic rehabilitations supported by implants in immediate function with the All-on-4®treatment concept using a computer guided surgical protocol (NobelGuide®, Nobel Biocare).
Materials and methods:
This retrospective clinical study included 111 edentulous patients (n = 53 bruxers; n = 21 smokers; n = 59 systemically compromised), rehabilitated between February 2005 and November 2010 with 532 implants with the All-on-4®treatment concept using NobelGuide®. Outcome measures were implant and prosthesis survival, marginal bone loss at 5-years and the incidence of mechanical and biological complications. Survival was calculated using life-table analysis. Inferential analysis was performed to compare the difference in marginal bone loss between axial and tilted implants.
Results:
Sixteen patients were lost to follow-up. The implant cumulative survival rate was 94.5% at 7 years. Prosthetic survival was 97.8% (n = 3 prosthetic failures). The average (standard deviation) marginal bone loss at 5 years was 1.3 mm (1.06 mm) overall, 1.27 mm (1.02 mm) for tilted implants and 1.34 mm (1.1 mm) for axial implants (p < .001). Ninety-one patients experienced complications in the provisional prostheses (n = 47 patients who were bruxers; n = 25 patients with implant-supported rehabilitation as opposing dentition) ranging from prosthetic fracture (n = 66 patients) to abutment or prosthetic screw loosening (n = 74 patients). Thirty-three patients experienced complications in the definitive prostheses (all exclusive to patients who were bruxers or had implant-supported rehabilitations as opposing dentition) ranging from acrylic-resin prosthetic/crown fracture (n = 23 patients) to abutment or prosthetic screw loosening (n = 10 patients). Twenty-five patients (22%) registered peri-implant pathology.
Conclusions:
Within the limitations of this study, it is possible to conclude that this treatment modality for completely edentulous jaws is possible with high long-term survival outcomes. Bruxing and smoking habits had a negative impact on implant failure, mechanical, and biological complications.
The need for cross-culturally adapted oral-health specific health outcome measures is increasingly recognized in Germany. Following accepted cultural adaptation technique guidelines, we report the development of the German version of the Oral Health Impact Profile (OHIP). The original 49 items were translated using a forward–backward method. A de novo development of German items established content validity. A priori hypothesized associations between the OHIP summary score and self-reported oral health and five oral disorders were confirmed in a random sample of the general population (n = 163, age 20–60 yr). These associations were interpreted as support for construct validity. The instrument's responsiveness, as indicated by a mean OHIP summary score change from 45.0 to 28.3, was established in 67 consecutive patients treated for temporomandibular disorder pain (age 19–85 yr; 72% women). Test-retest reliability was demonstrated by intraclass correlation coefficients of 0.63–0.92 for dimensions and summary scores (convenience sample, n = 30, age 18–85 yr; 53% women). Internal consistency was high (Cronbach's α > 0.74). Sufficient discriminative and evaluative psychometric properties of the Oral Health Impact Profile German version (OHIP-G) make the instrument suitable for assessment of oral health-related quality of life in cross-sectional as well as longitudinal studies.
Studies are needed to evaluate long-term outcomes of the All-on-4® treatment concept (Nobel Biocare AB) for rehabilitation of edentulous mandibles by assessing marginal bone levels and risk indicators for implant failure.
To evaluate 7-year clinical outcomes and 5-year radiographic outcomes of the All-on-4 treatment concept.
This retrospective case series included patients admitted for implant rehabilitations in the mandible, who were followed for 7 years clinically and 5 years radiographically. Primary outcome measures were cumulative prosthetic and implant survival using patient as the unit of analysis (Kaplan-Meier product limit estimator). Secondary outcome measure was marginal bone level (MBL) at 5 years. Variables associated with implant failure were analyzed using the Cox proportional hazards regression model to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Binary logistic regression was used to compute odds ratio (OR) with 95% CIs for variables associated with MBL ≥2.8 mm at 5 years.
A total of 324 patients (194 women, 130 men, average age = 58.9 years) were rehabilitated with 1,296 implants supporting 324 full-arch fixed immediately loaded mandibular prostheses. Sixty-four patients (19.8%) were lost to follow-up. Prosthetic survival was 323/324 (99.7%), and 14 patients lost 18 implants, with an estimated cumulative survival rate of 95.4% at 7 years. Variables associated with implant failure were smoking (HR = 5.28; 95% CI: 1.33, 20.91]) and the learning curve effect (0.69 < HR < 0.33 for more experienced levels). Mean MBL at 5 years was 1.81 mm (95% CI: 1.70, 1.92), and smoking was associated with MBL ≥2.8 mm (OR = 2.4; 95% CI: 1.02, 5.62).
The high implant and prosthetic survival rates and excellent MBL outcome confirm the predictability and safety of the All-on-4 treatment concept over a longer term than previously reported.
© 2014 Wiley Periodicals, Inc.
Objectives
To examine patients’ expectations, the level of satisfaction, and the oral health-related quality of life (OHRQoL) with regard to the implants’ immediate loading protocol (ILP) in edentate individuals.Methods
This pilot trial used a pre–post design to assess patient-centered outcomes in 18 edentate individuals (mean age 62.4 ± 7.7 years) who have received a 2-implant (unsplinted) mandibular overdenture through an ILP. Visual analog scales, the McGill denture satisfaction questionnaire, and the oral health impact profile (OHIP-20) questionnaire were used to evaluate patients’ expectations, satisfaction, and OHRQoL at baseline, 2 weeks, 1 month, and 4 months after surgery. Personality trait and socio-demographic information were obtained using the revised NEO personality inventory and a self-administered questionnaire, respectively. Non-parametric methods and Brunner–Langer approach were used to analyze the data.ResultsThe participants had a wide range of expectations regarding the ILP. Expectations included short-term positive impact on aesthetics (83.3%) and social life (55.7%), as well as negative effects on comfort (5.6%), the ability to chew (11.1%), and the ability to clean the lower denture (11.1%). The ILP satisfied 94.4% of the participants, regardless of socio-demographic and personality profiles. There was a statistically significant improvement in overall satisfaction, comfort, perceived aesthetics, stability of the overdenture, and ability to chew from baseline to 2-week, 1-, and 4-month follow-up (P < 0.001). There was 100% agreement among patients on recommending this procedure to others.There was a statistically significant decrease in the total OHIP scores and all its domains (P < 0.001) from baseline to 2 weeks. These differences remained statistically significant at 4-month follow-up. The ILP improved patients’ OHRQoL, regardless of the implant loss, the socio-demographic characteristics, and personality traits.Conclusions
The ILP of two unsplinted implants with a mandibular overdenture significantly improved satisfaction and short-term OHRQoL, and appears to meet expectations in edentulous elders. There was 100% agreement among patients on recommending this procedure to others.
Objective:
The aim of this study was to evaluate strain distribution in peri-implant bone, stress in the abutments and denture stability of mandibular overdentures anchored by different numbers of implants under different loading conditions, through three-dimensional finite element analysis (3D FEA).
Methods:
Four 3D finite element models of mandibular overdentures were established, using between one and four Straumann implants with Locator attachments. Three types of load were applied to the overdenture in each model: 100N vertical and inclined loads on the left first molar and a 100N vertical load on the lower incisors. The biomechanical behaviours of peri-implant bone, implants, abutments and overdentures were recorded.
Results:
Under vertical load on the lower incisors, the single-implant overdenture rotated over the implant from side to side, and no obvious increase of strain was found in peri-implant bone. Under the same loading conditions, the two-implant-retained overdenture showed more apparent rotation around the fulcrum line passing through the two implants, and the maximum equivalent stress in the abutments was higher than in the other models. In the three-implant-supported overdenture, no strain concentration was found in cortical bone around the middle implant under three loading conditions.
Conclusions and clinical significance:
Single-implant-retained mandibular overdentures do not show damaging strain concentration in the bone around the only implant and may be a cost-effective treatment option for edentulous patients. A third implant can be placed between the original two when patients rehabilitated by two-implant overdentures report constant and obvious denture rotation around the fulcrum line.
During recent years a new treatment concept, Brånemark Novum, has been developed in which implants are inserted in the edentulous lower jaw and immediately connected to a prefabricated titanium bar. A fixed prosthesis is then attached to the bar during or immediately following surgery.
The aim of the present study was to investigate the application of this concept under various settings, to determine technique sensitivity, and to evaluate the clinical outcome after 1 year of follow-up.
Fifty-one patients were included in a prospective multicenter investigation and followed up for 1 year. Cumulative implant survival rates were evaluated by life table analysis. In addition, clinical comparisons were performed to evaluate implant loss in relation to patient characteristics. Questionnaires were used to evaluate the treatment protocols and to obtain patients' opinions.
The prosthetic treatment was completed on the same or the following day in 76% of the patients. The cumulative implant survival rates for implants and prostheses were 91% and 94%, respectively, after 12 months.
The present study demonstrated that single-stage surgery and immediate loading of implants with prefabricated bridgework in the mandible can result in high implant success and significant reduction in treatment time, with patient satisfaction.
Abstract In this study the microbiota associated with oral endosteal titanium hollow cylinder implants (ITI) was studied using microscopic, immunochemical and cultural methods. Samples from 5 edentulous patients with successfully incorporated implants serving as abutments for overdentures for more than one year were compared with samples from 7 patients with clinically failing implants. Unsuccessful sites were characterized by pocket probing depths of 6 mm or more, suppuration and visible loss of alveolar bone around the implant as visualized on radiographs. These sites harbored a complex microbiota with a large proportion of Gram-negative anaerobic rods. Black-pigmented Bacteroides and Fusobacterium spp. were regularly found. Spirochetes, fusiform bacteria as well as motile and curved rods were a common feature in the darkfield microscopic specimens of these sites. Control sites in the same patients harbored small amounts of bacteria. The predominant morphotype was coccoid cells. Spirochetes were not present, fusiform bacteria, motile and curved rods were found infrequently and in low numbers. The microbiota in control sites in unsuccessful patients and in site in successful patients were very similar. On the basis of these results, it is suggested that “periimplantitis” be regarded as a site specific infection which yields many features in common with chronic adult periodontitis.
Immediate-function Brånemark System® implants (Nobel Biocare AB, Gothenburg, Sweden) have become an accepted alternative for fixed restorations in edentulous mandibles, based on documented high success rates. Continuous development is ongoing to find simple protocols for their use.
The purpose of this study was to develop and document a simple, safe, and effective surgical and prosthetic protocol for immediate function (within 2 hours) of four Brånemark System implants supporting fixed prostheses in completely edentulous mandibles: the “All-on-Four” concept.
This retrospective clinical study included 44 patients with 176 immediately loaded implants, placed in the anterior region, supporting fixed complete-arch mandibular prostheses in acrylic. In addition to the immediately loaded implants, 24 of the 44 patients had 62 rescue implants not incorporated in the provisional prostheses but incorporated in final prostheses later on.
Five immediately loaded implants were lost in five patients before the 6-month follow-up, giving cumulative survival rates of 96.7 and 98.2% for development and routine groups, respectively. The prostheses' survival was 100%, and the average bone resorption was low.
The high cumulative implant and prostheses survival rates indicate that the “All-on-Four” immediate-function concept with Brånemark System implants used in completely edentulous mandibles is a viable concept.
The purpose of this study was to evaluate a specific protocol using four implants to support immediately loaded fixed prostheses to restore edentulous and partially edentulous mandibles and report on the outcome after 1 year of function with the definitive prostheses.
A retrospective study was conducted of all patients who were treated between June 2008 and December 2010 with fixed prostheses that were loaded immediately after placement of implants. The provisional prostheses were later replaced with computer-aided design/computer-assisted manufacture titanium frames supporting acrylic resin and denture teeth in the definitive prosthesis. All patients were followed for a minimum of 12 months and were assessed for implant survival and prosthetic performance, with descriptive statistics utilized to demonstrate results.
One hundred eighty-three consecutive patients received immediately loaded axial and tilted implants according to the defined protocol. One implant failed, resulting in a 99.86% implant success rate. There were two catastrophic prosthetic failures (fracture of the titanium framework), for a 98.9% prosthetic success rate. Three patients (1.6%) presented with fracture of a prosthetic mandibular incisor tooth. No prosthetic screw loosening or fractures were seen. Radiographic evaluation revealed no major bone loss around dental implants.
Based on this retrospective study, the following conclusions can be drawn: (1) this technique appears to provide a highly predictable implant performance; (2) it is necessary to critically evaluate framework design, especially around the connectors for cantilever extensions around the most distal implants; and (3) minor complications related to acrylic resin tooth fracture may be anticipated during the early phases of prosthetic treatment.
To report the outcome of an implant therapy protocol using 4 or 6 implants supporting immediately loaded fixed prostheses following 3D software planning and flapless guided surgery.
A total of 30 patients (24 women, 6 men), mean age of 53 years (range 35-84 years) were treated with 195 immediately loaded implants (97 NobelSpeedy Groovy and 98 Brånemark MKIII Groovy) supporting 25 maxillary and 17 mandibular fixed full-arch acrylic prostheses and followed for 1 year. The Procera Software v1.6 and v2.0 was used to plan implant position and to obtain a surgical template for the guided flapless implant placement. To perform immediate loading, the implants had to be inserted with torque of at least 35 Ncm. Provisional prostheses were made before surgery using software planning and were placed in the same session as the implants. Definitive restorations were delivered 6-12 months after surgery. Outcome measures were failures of the prosthesis and of the implants, marginal bone level changes, complications, clinical time and patient satisfaction.
Four patients with full edentulism and 26 with advanced periodontitis were enrolled in this study. A total of 195 implants were immediately loaded (128 implants were placed in the maxilla and 67 implants were placed in the mandible). Four implants out of 195 failed in three patients during the healing period: 2 in the maxilla (1 straight and 1 tilted), and 2 in the mandible (both of them tilted). Three of them were successfully replaced. One year after loading there were no dropouts and no failure of the definitive prosthesis occurred. In three cases, the surgical template fractured during surgery. In one patient, a new impression had to be taken to fit the provisional prosthesis onto the implants. Three patients were subjected to surgery and systemic antibiotics to treat apically infected implants.
The 'all-on-four' and 'all-on-six' treatment protocol combined with computer-guided flapless implant surgery could be a viable and predictable treatment. Some complications occurred that were successfully treated. However, this technique could be sensitive to the experience of the surgeon and a learning curve is required.
To present clinical results of an implant placement protocol using 4 or 6 implants supporting immediately loaded fixed prostheses.
This retrospective clinical study included 20 patients (restoring 19 maxillae and 9 mandibles) with 127 loaded implants that supported immediately fixed complete-arch acrylic prostheses followed for at least 2 years. Outcome measures were failures of the prosthesis and of the implants, an approximate radiographic evaluation, and any complication.
A total of 116 implants were immediately loaded. Eleven implants were not immediately loaded because they did not reach the planned insertion torque. These implants were loaded after the osseointegration period when the final prostheses were delivered. Four implants failed during the osseointegration period and all of them were successfully replaced. The survival rate was 96.9% (96.7% in the maxilla and 97.2% in the mandible). No prosthesis was lost. Eight patients experienced fractures of their provisional prosthesis that were repaired in the clinic. Seven implants out of 127 experienced marginal bone loss up to the first and the second thread.
The results indicate that the 'all on four' and 'all on six' immediate-function concept postextraction could be a viable and predictable treatment.
This review describes practical criteria and a systematic process to aid the treatment planning decision of whether to preserve teeth by root canal treatment (RCT) or extract and provide an implant. Recommendations presented are based on best available evidence from the literature and the expert views of specialists in endodontics and restorative dentistry, including dental implantology. A MEDLINE search was conducted using the terms 'root canal therapy', 'dental implants', 'decision making', 'treatment planning', 'outcome' and 'human', and supplemented by hand-searching. When evaluating the outcome of root canal treatment, an observation period of 4-5 years is required for complete healing of periapical lesions. Dental implants, however, present a de novo situation and a functional period of at least 5 years is often required before peri-implant diseases are established and detected. Good long-term success rates and greater flexibility in clinical management indicate that RCT or retreatment should be performed first in most instances unless the tooth is judged to be unrestorable. When deciding if a compromised tooth of questionable prognosis should be maintained or replaced by an implant, both local, site-specific and more general patient-related factors should be considered. Following systematic evaluation and consideration of the best treatment option in a particular case, a treatment recommendation may then be given in favour or against tooth retention. Whilst single risks are possibly accepted for single tooth restorations, teeth with questionable prognosis and multiple pre-treatment requirements are better not included as abutments in fixed dental prostheses to reduce the risk to survival of the entire restoration.
In the past decade, the technique of osseointegration has elicited three general responses in the dental profession. The first and major response has been an enormous clinical satisfaction to resolve difficult prosthetic problems, as well to expand the scope and range of routing prosthetic therapy. A second, if minor, response has been an attempt to deny the documented apparent superiority of the osseointegrated method. The third response has been a very active marketing one, which led to the rapid proliferation of a large number of implant systems, all claiming osseointegration and comparable success to the originally introduced Swedish system. The purpose of this paper is to describe and analyze those clinical criteria which can be used by dentist and researcher to determine the long term success or failure of functioning dental implants. Some attempts had been made to identify criteria which reflected sound scientific consideration of long term host acceptance of functioning implants. However, these criteria where a reflection of the state of the art information as perceived by the authors at the time. It is therefore fair to add that the principle of osseointegration did not feature in our colleagues recommendations. Since it is an axiom that host response must be analyzed and understood if a clinical technique is to be successfully prescribed, we regarded our own and other's published data on clinical results with osseointegration as pivotal in the grouping of criteria which would comprise a reliable yardstick, easy to identify and apply, and which reflected assessment experiences in dental practice and research, mainly in the disciplines of periodontics and prosthodontics.(ABSTRACT TRUNCATED AT 400 WORDS)
Brånemark fixtures were originally prescribed to be placed in two surgical stages. During the past years, reports on the placement of machined titanium implants in a one-stage procedure have been published, and the results have been encouraging. Recently there has been considerable interest in early or immediate loading.
The purpose of this article is to report the preliminary clinical results of a new method for implant treatment of the edentulous mandible. The new protocol involves prefabricated components and surgical guides, elimination of the prosthetic impression procedure and attachment of the permanent fixed bridge on the day of implant placement.
Fifty patients (26 males, 24 females) received 150 Brånemark Novum implants and were followed from 6 months to 3 years after implant placement. Bone width and height were determined preoperatively with the use of radiographs. The jaw was reduced in height to accommodate three special 5-mm wide implants. Precise implant positioning was accomplished with special drilling templates. Drill guides were placed over the drilling templates during site preparation using a series of specially designed drills. After the mucosa had been sutured back into position, a prefabricated titanium lower bar was connected with titanium screws to the transmucosal fixture. Another titanium bar was then attached by the prosthodontist, and a bite registration was performed. The bridge was attached to the upper bar. The permanent reconstruction was provided to the patient later the same day.
Three implants were lost to follow-up and three failed, resulting in an overall survival rate of 98%. One prosthesis failed, leaving a prosthetic survival rate of 98%. The average treatment time was approximately 7 hours. At the baseline examination, the marginal bone level was 0.72 mm below the reference point. The average marginal bone loss was 0.2 mm per year and 0.26 mm between the 3-month and 1-year control visits. The accumulated mean bone loss, including baseline, was -1.25 mm. A patient questionnaire demonstrated that 94% of the patients did not experience any discomfort during treatment and all patients would recommend the procedure to others.
The results of this study indicate that the precise surgical and prosthetic protocol allows successful prosthetic rehabilitation of mandibular edentulism and that the permanent reconstruction can be provided to the patient on the day of fixture surgery.
The long-term predictability reported with the traditional two-staged Brånemark method has led to developments aimed at simplifying the technique and reducing healing time. Results from a pilot study using the Brånemark Novum concept are promising, and it has been shown possible to fabricate and deliver an implant-supported fixed prosthesis to the patient on the day of surgery.
The objective of this study is to report clinical and radiographic outcomes in a group of patients treated according to the Brånemark Novum concept.
Ninety-five patients with edentulous mandibles were consecutively included in the study. Three specially designed fixtures were placed in each patient (285 fixtures in total) using drilling templates. The fixtures were immediately splinted with a prefabricated substructure, and fixed prostheses were delivered the same day in 67% of the patients. For the rest, prosthesis delivery ranged from 1 to 40 days (mean 5.6 d). Clinical and radiographic examinations were performed after 3 months, 6 months, 1 year, and then annually. The follow-up time was 1 to 5 years (mean 2.5 yr).
The cumulative prosthesis survival rate was 99%. Eighteen fixtures (6.3%) failed in 13 patients. Kaplan-Meier survival estimates demonstrated a probability implant survival at 1 year of 95.0% (94 patients), at 3 years of 93.3% (47 patients), and at 5 years of 93.3% (9 patients). The mean bone loss was 0.73 mm between the examinations at 3 months and 1 year, 0.16 mm during the second year, and 0.13 mm annually during years 3 to 5.
Comparable results, related to continuous prosthesis stability, were shown for the Novum approach compared with the traditional two-staged procedure. Survival of individual fixtures is lower when immediate loading is applied.
The influence of implant number and cantilever design on stress distribution on bone has not been sufficiently assessed for the mandibular overdenture.
The purpose of this simulation study was to measure, photoelastically, the biologic behavior of 2 or 3 implants retaining different designs of cantilevered bar mandibular overdentures and to compare load characteristics.
Two photoelastic models of a human edentulous mandible were fabricated having 2 or 3 screw-type implants (Nobel Biocare, 3.75 x 10mm) embedded in the parasymphyseal area. Bar frameworks using a 7-mm cantilever were fabricated for both models. A clip-retained and a plunger-retained (SwissLoc) prosthesis were fabricated as superstructures for each framework. Vertical loads of 15 and 30 pounds were applied unilaterally to the first molar and 15 pounds to the first premolar on each of the 4 standardized overdenture prostheses. The cantilever was removed from the 2-implant framework and the clip-retained prosthesis was loaded similarly on the first molar with 25 pounds. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically.
While all 4 prostheses demonstrated low stress transfer to the implants, the plunger-retained prosthesis caused more uniform stress distribution to the ipsilateral terminal abutment compared to the clip-retained prosthesis and provided retention security under tested loads. The plunger-retained prosthesis retained by 2 implants provided better load sharing from the ipsilateral edentulous ridge than the clip-retained prosthesis retained by 3 implants, and lower resultant stresses were seen on the implants.
Under load, all prosthetic designs demonstrated a low stress transfer to the ipsilateral abutment and to the contralateral side of the arch. The plunger-retained prosthesis retained by 2 implants demonstrated a more uniform stress transfer to the ipsilateral terminal abutment than the clip-retained prosthesis retained by 3 implants and provided more retention, given the implant configuration, prosthetic design and arch form.
Misch’s avoiding complications in oral implantology
- R Resnick