Numerical study of effect of elastomeric stress absorbers on stress reduction in bone-dental implant interface

Objective

This paper focused on optimal stress distribution in the mandibular bone surrounding a dental implant and is devoted to the development of a modified Osteoplant^® implant type in order to minimize stress concentration in the bone-implant interface.

Material and Methods

This study investigated 0.4 mm thick layers of two elastomeric stress barriers incorporated into the dental implant using 3-D finite element analysis.

Results

Overall, this proposed implant provoked lower load transfer in bone-implant interface due to the effect of the elastomers as stress absorbers. The stress level in the bone was reduced between 28% and 42% for three load cases: 75 N, 60 N and 27 N in corono-apical, linguo-buccal and disto-mesial direction, respectively.

Conclusion

The proposed model provided an acceptable solution for load transfer reduction to the mandible. This investigation also permitted to choose how to incorporate two elastomers into the Osteoplant^® implant system.     

Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading

PURPOSE

Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading.

MATERIALS AND METHODS

Two dimensional finite element models of cylinderical implant, abutments and bone made by titanium or polyoxymethylene were simulated with the aid of Marc/Mentat software. Each model represented bone, implant and titanium or polyoxymethylene abutment. Model 1: Implant with 3 mm titanium abutment, Model 2: Implant with 2 mm polyoxymethylene resilient material abutment, Model 3: Implant with 3 mm polyoxymethylene resilient material abutment and Model 4: Implant with 4 mm polyoxymethylene resilient material abutment. A vertical load of 11 N was applied with a frequency of 2 cycles/sec. The stress distribution pattern and displacement at the junction of cortical bone and implant was recorded.

RESULTS

When Model 2, 3 and 4 are compared with Model 1, they showed narrowing of stress distribution pattern in the cortical bone as the height of the polyoxymethylene resilient material abutment increases. Model 2, 3 and 4 showed slightly less but similar displacement when compared to Model 1.

CONCLUSION

Within the limitation of this study, we conclude that introduction of different height resilient material abutment with different heights i.e. 2 mm, 3 mm and 4 mm polyoxymethylene, does not bring about significant change in stress distribution pattern and displacement as compared to 3 mm Ti abutment. Clinically, with the application of resilient material abutment there is no significant change in stress distribution around implant-bone interface.     

Three-dimensional finite element analysis of implant-supported crown in fibula bone model

PURPOSE

The purpose of this study was to compare stress distributions of implant-supported crown placed in fibula bone model with those in intact mandible model using three-dimensional finite element analysis.

MATERIALS AND METHODS

Two three-dimensional finite element models were created to analyze biomechanical behaviors of implant-supported crowns placed in intact mandible and fibula model. The finite element models were generated from patient''s computed tomography data. The model for grafted fibula was composed of fibula block, dental implant system, and implant-supported crown. In the mandible model, same components with identical geometries with the fibula model were used except that the mandible replaced the fibula. Vertical and oblique loadings were applied on the crowns. The highest von Mises stresses were investigated and stress distributions of the two models were analyzed.

RESULTS

Overall stress distributions in the two models were similar. The highest von Mises stress values were higher in the mandible model than in the fibula model. In the individual prosthodontic components there was no prominent difference between models. The stress concentrations occurred in cortical bones in both models and the effect of bicortical anchorage could be found in the fibula model.

CONCLUSION

Using finite element analysis it was shown that the implant-supported crown placed in free fibula graft might function successfully in terms of biomechanical behavior.     

Does matching relation exist between the length and the tilting angle of terminal implants in the all-on-four protocol? stress distributions by 3D finite element analysis

PURPOSE

To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework.

MATERIALS AND METHODS

Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle (0°, 30° and 45°) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point.

RESULTS

1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress.

CONCLUSION

Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.     

A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE

This study evaluated the initial stability of different implants placed above the bone level in different types of bone.

MATERIALS AND METHODS

As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Brånemark System® Mk III TiUnite™, Straumann Standard Implant SLA®, and Astra Tech Microthread™-OsseoSpeed™) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis.

RESULTS

In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Brånemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants.

CONCLUSION

The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.     

Resorption of labial bone in maxillary anterior implant

PURPOSE

The purpose of this study was to evaluate the amount of resorption and thickness of labial bone in anterior maxillary implant using cone beam computed tomography with Hitachi CB Mercuray (Hitachi, Medico, Tokyo, Japan).

MATERIALS AND METHODS

Twenty-one patients with 26 implants were followed-up and checked with CBCT. 21 OSSEOTITE NT® (3i/implant Innovations, Florida, USA) and 5 OSSEOTITE® implants (3i/implant Innovations, Florida, USA) were placed at anterior region and they were positioned vertically at the same level of bony scallop of adjacent teeth. Whenever there was no lesion or labial bone was intact, immediate placement was tried as possible as it could be. Generated bone regeneration was done in the patients with the deficiency of hard tissue using Bio-Oss® (Geistlich, Wolhusen, Switzerland) and Bio-Gide® (Geistlich, Wolhusen, Switzerland). Second surgery was done in 6 months after implant placement and provisionalization was done for 3 months. Definite abutment was made of titanium abutment with porcelain, gold and zirconia, and was attached after provisionalization. Two-dimensional slices were created to produce sagittal, coronal, axial and 3D by using OnDemand3D (Cybermed, Seoul, Korea).

RESULTS

The mean value of bone resorption (distance from top of implant to labial bone) was 1.32 ± 0.86 mm and the mean thickness of labial bone was 1.91 ± 0.45 mm.

CONCLUSION

It is suggested that the thickness more than 1.91 mm could reduce the amount and incidence of resorption of labial bone in maxillary anterior implant.     

Results of immediate loading for implant restoration in partially edentulous patients: a 6-month preliminary prospective study using SinusQuick? EB implant system

STATEMENT OF PROBLEM

Many dental clinicians are concerned about immediate loading of inserted implants. However, there have been few clinical studies surveying the success rates of immediate loading, based on Korean implant systems.

PURPOSE

The aim of this study was to evaluate the outcome of immediate functional loading of the implant (SinusQuick™ EB, Neobiotech Co., Seoul, Korea) in partially edentulous maxilla or mandible.

MATERIAL AND METHODS

Total 15 implants were placed. Within 2 weeks after implant insertion, provisional implant-supported fixed partial dentures were delivered to the patients. Quantitatively, marginal bone loss was measured at the time of immediate loading, after 3-months of continued loading and at the last follow-up. The mean follow-up period was 4.8 months.

RESULTS

Mean marginal bone loss from implant surgery to early loading, 3-months follow-up and last follow-up was 0.03 ± 0.07 mm, 0.16 ± 0.17 mm and 0.29 ± 0.19 mm. No implant failed up to 6 months after insertion, resulting in a 100% survival rate.

CONCLUSION

Immediate loading exhibited high success rate in partial edentulism for up to 6 months. Well-controlled long term clinical studies with large sample size are necessary to confirm this finding.     

The effect of zirconia framework design on the failure of all-ceramic crown under static loading

PURPOSE

This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading.

MATERIALS AND METHODS

Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test.

RESULTS

The mean and standard deviations of the failure load were 1,170.1 ± 90.9 N for EV design and 1,450.4 ± 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples).

CONCLUSION

There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.     

Comparison Between Physics and Conventional Forceps in Simple Dental Extraction

Background

Atraumatic dental extraction preserves bone, gingival architecture, and allows for the option of future or immediate dental implant placement. A number of tools and techniques have been proposed for minimally invasive tooth removal such as physics forceps. The biomechanical design of physics forceps decreases the incidence of root fracture, and maintains the buccal bone plate, which is essential for the proper healing of an immediately placed dental implant.

Purpose

This study was conducted to evaluate the efficacy of physics forceps versus conventional forceps in simple dental extraction.

Patients and Methods

200 adult patients seeking simple dental extraction were selected from the Outpatient Clinic in the Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Mansoura University, Egypt. The selected patients were randomly allocated into two groups: group I: included 100 patients, in this group extraction was done using physics forceps, and group II: included 100 patients, in this group extraction was done using conventional forceps.

Results

In physics forceps group: crown fracture occurred in three cases (3 %), buccal bone fracture occurred in three cases (3 %), and root fracture occurred in 14 roots (8.5 %), while in conventional forceps group: crown fracture occurred in 10 cases (10 %), buccal bone fracture occurred in seven cases (7 %), and root fracture occurred in 27 roots (16.6 %).

Conclusion

Physics forceps are innovative extraction instruments. By using them, it is possible to perform difficult extractions, with predictable results, and without need to reflect a flap. Using physics forceps decreases the incidence of crown, root, and buccal bone plate fractures, in comparison to the conventional forceps.     

Evaluation of Vertical Bone Gain Following Alveolar Distraction Osteogenesis in the Anterior Edentulous Mandible: A Clinical Study

Aim and Objectives

To calculate the gain in bony height and volume of the distracted upper segment using an extraosseous unidirectional device to improve the retention of the future prosthesis.

Materials and Methods

Ten cases with completely or partially edentulous but severely or considerably resorbed anterior mandibles were managed by vertical alveolar distraction osteogenesis. All the patients were evaluated preoperatively, intraoperatively and post-operatively for various parameters clinically and radiographically i.e. on OPG, lateral cephalogram and on CT scan, at different time intervals. In all cases there was increase in vertical bone height.

Results

The study showed mean vertical bone gain (VBG) on OPG as 8.2 mm. The mean VBG on lateral cephalogram was 8.1 mm. The mean VBG on CT scan at right canine was 8.35 mm, at left canine was 8.2 mm and at midline was 8.27 mm.

Conclusion

Alveolar distraction osteogenesis is a predictable method for restoring alveolar ridges prior to implant placement or prosthesis. Distraction osteogenesis is ideally suited for recreating missing tissue in the anterior esthetic zone by increasing vertical bone height as well as good width and soft tissue growth.     

Effect of loading time on the survival rate of anodic oxidized implants: prospective multicenter study

PURPOSE

The purpose of this prospective study was to evaluate the effect of early loading on survival rate or clinical parameter of anodic oxidized implants during the 12-month postloading period.

MATERIALS AND METHODS

Total 69 implants were placed in 42 patients. Anodic oxidized implants (GS II, Osstem Cor., Busan, Korea) placed on the posterior mandibles were divided into two groups, according to their prosthetic loading times: test group (2 to 6 weeks), and control group (3 to 4 months). The implant survival rates were determined during one-year postloading period and analyzed by Kaplan-Meier method. The radiographic peri-implant bone loss and periodontal parameters were also evaluated and statistically analyzed by unpaired t-test.

RESULTS

Total 69 implants were placed in 42 patients. The cumulative postloading implant survival rates were 88.89% in test group, compared to 100% in control group (P<.05). Periimplant marginal bone loss (T: 0.27±0.54 mm, C: 0.40±0.55 mm) and periodontal parameters showed no significant difference between the groups (P>.05).

CONCLUSION

Within the limitation of the present study, implant survival was affected by early loading on the anodic oxidized implants placed on posterior mandibles during one-year follow-up. Early implant loading did not influence peri-implant marginal bone loss, and periodontal parameters.     

Periodontal ligament influence on the stress distribution in a removable partial denture supported by implant: a finite element analysis

ABSTRACT

Objective

The non-homogenous aspect of periodontal ligament (PDL) has been examined using finite element analysis (FEA) to better simulate PDL behavior. The aim of this study was to assess, by 2-D FEA, the influence of non-homogenous PDL on the stress distribution when the free-end saddle removable partial denture (RPD) is partially supported by an osseointegrated implant.

Material and Methods

Six finite element (FE) models of a partially edentulous mandible were created to represent two types of PDL (non-homogenous and homogenous) and two types of RPD (conventional RPD, supported by tooth and fibromucosa; and modified RPD, supported by tooth and implant [10.00x3.75 mm]). Two additional FE models without RPD were used as control models. The non-homogenous PDL was modeled using beam elements to simulate the crest, horizontal, oblique and apical fibers. The load (50 N) was applied in each cusp simultaneously. Regarding boundary conditions the border of alveolar ridge was fixed along the x axis. The FE software (Ansys 10.0) was used to compute the stress fields, and the von Mises stress criterion (σvM) was applied to analyze the results.

Results

The peak of σvM in non-homogenous PDL was higher than that for the homogenous condition. The benefits of implants were enhanced for the non-homogenous PDL condition, with drastic σvM reduction on the posterior half of the alveolar ridge. The implant did not reduce the stress on the support tooth for both PDL conditions.

Conclusion

The PDL modeled in the non-homogeneous form increased the benefits of the osseointegrated implant in comparison with the homogeneous condition. Using the non-homogenous PDL, the presence of osseointegrated implant did not reduce the stress on the supporting tooth.     

Influence of preparation depths on the fracture load of customized zirconia abutments with titanium insert

PURPOSE

This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging.

MATERIALS AND METHODS

Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a 4.5×10 mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: 5-55℃, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression.

RESULTS

The fracture loads were 539.28 ± 63.11 N (N5), 406.56 ± 28.94 N (N7), 366.66 ± 30.19 N (N9), 392.61 ± 50.57 N (A5), 317.94 ± 30.05 N (A7), and 292.74 ± 37.15 N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05).

CONCLUSION

The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.     

Long-term outcome of dental implants after maxillary augmentation with and without bone grafting

Background

This study aims to evaluate the technique of sinus bone reformation, which consists of elevating the sinus membrane and placement the implant without bone graft, compared with the widely-used technique involving raising the maxillary sinus and grafting, using animal hydroxyapatite as the filler, while simultaneously fixing the implants.

Material and Methods

This is a retrospective study on two groups of patients who underwent elevation of the sinus membrane and simultaneous placement of the implant. The grafting technique was applied to one group, while the other had no graft. An alveolar ridge height of 4 to 7 mm was necessary. Radiological control was undertaken at 6 months and one year post-prosthetic loading. In each group 38 implants were placed.

Results

No significant behavioural differences were observed in the implants according to the Albrektsson success criteria. Implant failure was observed in 2 implants from the bone grafting group (success rate 93%) and in 1 implant from the reformation group (success rate 97%). In this group, bone formation was observed on both sides of each implant, the bone gain was measured using image management software (2.7±0.9mm mesial and 2.6±0.9mm distal). There was no correlation between mesial and distal bone gain and implant´s length.

Conclusions

The results indicate that bone reformation is a valid technique in cases involving atrophy of the posterior maxilla. Primary stability, maintenance of space by the implant, and the formation of a blood clot are crucial in this technique in order to achieve bone formation around the implant. It is an alternative to the conventional technique of sinus lift with filling material, and has several advantages over this procedure, including a lower infection risk, as it does not involve a biomaterial, reduced cost, a simpler technique, and better acceptance by the patient. Key words:Bone formation, sinus membrane elevation, maxillary sinus, bone grafting.     

Mechanical analysis of conventional and small diameter conical implant abutments

PURPOSE

The aim of the present study was to evaluate if a smaller morse taper abutment has a negative effect on the fracture resistance of implant-abutment connections under oblique compressive loads compared to a conventional abutment.

MATERIALS AND METHODS

Twenty morse taper conventional abutments (4.8 mm diameter) and smaller abutments (3.8 mm diameter) were tightened (20 Ncm) to their respective implants (3.5 × 11 mm) and after a 10 minute interval, implant/abutment assemblies were subjected to static compressive test, performed in a universal test machine with 1 mm/min displacement, at 45° inclination. The maximum deformation force was determined. Data were statistically analyzed by student t test.

RESULTS

Maximum deformation force of 4.8 mm and 3.8 mm abutments was approximately 95.33 kgf and 95.25 kgf, respectively, but no fractures were noted after mechanical test. Statistical analysis demonstrated that the evaluated abutments were statistically similar (P=.230).

CONCLUSION

Abutment measuring 3.8 mm in diameter (reduced) presented mechanical properties similar to 4.8 mm (conventional) abutments, enabling its clinical use as indicated.     

Sinus Elevation with an Alloplastic Material and Simultaneous Implant Placement: A 1-Stage Procedure in Severely Atrophic Maxillae

Aims and objective

The aim of the study is to evaluate clinically and radiographically the long term success of one-stage direct (lateral) sinus lift procedure using alloplastic bone graft material and bio-absorbable membrane in conjunction with two stage implant placement in atrophic partially edentulous posterior maxilla.

Materials and methods

One stage direct maxillary sinus lift in conjunction with two stage implant placement was carried out in 12 patients at 13 sites. All the patients were partially edentulous with posterior maxillary alveolar ridge height of >5 mm and were in the age group of 20–50 years. Bioactive glass putty, bio-absorbable collagen membrane and 3.75 × 11.5 mm implants were used. Loading of implants was done 6 months after placement of implants. Patients were evaluated clinically and radio-graphically 6, 18, 30 months after placement of implants to assess increase in residual ridge height, peri-implant condition (marginal bone loss, plaque and gingival index) and implant stability.

Results

Maxillary first molar was the most common site (69.23 %) for sinus lift and implant placement. Caries was the most common cause (76.92 %) for loss of tooth. Increase in residual ridge height ranged from (71.43 to 133.33 %) as measured by Denta-Scan. Implant survival rate was 100 %. Marginal bone loss ranged from 0.68 to 1.22 mm. Implant stability was measured by periotest (−2.7 to −3.6). Only one patient had perforation of sinus membrane, but it was sealed satisfactorily by bio-absorbable membrane.

Conclusion

One stage lateral sinus lift procedure with alloplastic bone graft material in combination with 2 stage implant placement has a predictable outcome in patients with severe resorption of posterior maxilla.     

Effect of different restorative crown and customized abutment materials on stress distribution in single implants and peripheral bone: A three-dimensional finite element analysis study

Statement of problem

In recent years, the use of resin-matrix ceramics and polyetheretherketone (PEEK) abutments has been suggested to absorb excessive stresses on dental implants. However, only a few studies have evaluated the effect of these materials on stress distribution in implants and peripheral bone structure.

Long-term cumulative survival and mechanical complications of single-tooth Ankylos Implants: focus on the abutment neck fractures

PURPOSE

To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth Ankylos® implants.

MATERIALS AND METHODS

This was a retrospective clinical study that analyzed 450 single Ankylos® implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position.

RESULTS

The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05).

CONCLUSION

The Ankylos® implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.     

Maxillary Sinus Augmentation with Autologous and Heterologous Bone Graft: A Clinical and Radiographic Report of Immediate and Delayed Implant Placement

Purpose

The aim of this study was to evaluate cumulative survival rate of implants placed on augmented maxillary sinus using a mixture of autologous bone harvested from the maxillary tuberosity and bovine-derived HA and to assess the height of the grafted material through radiographic evaluation.

Methods

Thirty-five patients were treated with maxillary sinus augmentation and 93 implant fixtures were installed. The height of the augmented sinus and the gain of bone volume were measured by Cone Beam CT Scan and intraoral radiographs immediately after augmentation and up to 48 months subsequently. Changes in the height of the sinus graft material were calculated radiographically.

Results

The cumulative survival rate was 98.92 % in all 93 implants. Additionally, normal healing process without any complication was observed in all patients. The original sinus height was a mean of 4.52 mm (range 2.0–6.4 mm) and the augmented sinus height was a mean of 14.1 mm (range 12.0–16.5 mm) after the surgery. The bone volume gain was a mean 9.613 mm (range 7–13 mm).

Conclusions

Within the limitations of this study, it would appear from the clinical and radiographic results that the sinus lift procedure with autologous bone graft harvested from the maxillary tuberosity combined with deproteinized bovine bone allows for a predictable outcome regarding the amount of bone formation in sinus floor augmentation and the immediate placement of implants, when possible, is recommended.