Ilser Turkyilmaz

Clinical Accuracy of 3 Different Types of Computed Tomography-Derived Stereolithographic Surgical Guides in Implant Placement

PURPOSE Presurgical planning is essential to achieve esthetic and functional implants. The goal of this clinical study was to determine the angular and linear deviations at the implant neck and apex between planned and placed implants using stereolithographic (SLA) surgical guides. PATIENTS AND METHODS A total of 110 implants were placed using SLA surgical guides generated from computed tomography (CT). All patients used the radiographic templates during CT scanning. After obtaining 3-dimensional CT scans, each implant insertion was simulated on the CT images. SLA surgical guides using a rapid prototyping method including a laser beam were used during implant insertion. A new CT scan was made for each patient after implant insertion. Special software was used to match images of the planned and placed implants, and their positions and axes were compared. RESULTS The mean angular deviation of all placed implants was 4.1 degrees+/-2.3 degrees, whereas mean linear deviation was 1.11+/-0.7 mm at the implant neck and 1.41+/-0.9 mm at the implant apex compared with the planned implants. The angular deviations of the placed implants compared with the planned implants were 2.91 degrees+/-1.3 degrees, 4.63 degrees+/-2.6 degrees, and 4.51 degrees+/-2.1 degrees for the tooth-supported, bone-supported, and mucosa-supported SLA surgical guides, respectively. CONCLUSION The results of this study suggested that stereolithographic surgical guides using CT data may be reliable in implant placement, and tooth-supported SLA surgical guides were more accurate than bone- or mucosa-supported SLA surgical guides.

Influence of bone density on implant stability parameters and implant success: a retrospective clinical study

BackgroundThe aim of the present clinical study was to determine the local bone density in dental implant recipient sites using computerized tomography (CT) and to investigate the influence of local bone density on implant stability parameters and implant success.MethodsA total of 300 implants were placed in 111 patients between 2003 and 2005. The bone density in each implant recipient site was determined using CT. Insertion torque and resonance frequency analysis were used as implant stability parameters. The peak insertion torque values were recorded with OsseoCare machine. The resonance frequency analysis measurements were performed with Osstell instrument immediately after implant placement, 6, and 12 months later.ResultsOf 300 implants placed, 20 were lost, meaning a survival rate of %. 93.3 after three years (average 3.7 ± 0.7 years). The mean bone density, insertion torque and RFA recordings of all 300 implants were 620 ± 251 HU, 36.1 ± 8 Ncm, and 65.7 ± 9 ISQ at implant placement respectively; which indicated statistically significant correlations between bone density and insertion torque values (p < 0.001), bone density and ISQ values (p < 0.001), and insertion torque and ISQ values (p < 0.001). The mean bone density, insertion torque and RFA values were 645 ± 240 HU, 37.2 ± 7 Ncm, and 67.1 ± 7 ISQ for 280 successful implants at implant placement, while corresponding values were 267 ± 47 HU, 21.8 ± 4 Ncm, and 46.5 ± 4 ISQ for 20 failed implants; which indicated statistically significant differences for each parameter (p < 0.001).ConclusionCT is a useful tool to determine the bone density in the implant recipient sites, and the local bone density has a prevailing influence on primary implant stability, which is an important determinant for implant success.

Biomechanical aspects of primary implant stability: a human cadaver study.

BACKGROUND The quality of bone is an important factor in the successful implant treatment, and it is evident that higher implant failure is more likely in poor quality of bone. The primary stability of oral implants related to resistance to micromotion during healing is influenced by bone quality, surgical technique, and implant design. PURPOSES The aims of this biomechanical study were to explore the effect of bone quality on initial intraosseous stability of implants, and to determine the correlations between the bone quality and implant stability parameters. MATERIALS AND METHODS Twenty-four implants (Neoss Ltd., Mölnlycke, Sweden) were placed into anterior and posterior regions of three human cadaver mandibles. The bone densities of implant recipient sites were preoperatively determined using computerized tomography (CT) in Hounsfield unit (HU). The maximum insertion torque values were recorded, and primary implant stability measurements were noninvasively performed by means of resonance frequency analysis (RFA). RESULTS The bone density values ranged from -267 HU to 553 HU. It was found that mean bone density, insertion torque, and RFA values were 113 +/- 270 HU, 41.9 +/- 5 Ncm, and 70 +/- 7 implant stability quotient (ISQ), respectively. Statistically significant correlations were found between bone density and insertion torque values (r = 0.690, p < .001); bone density and ISQ values (r = 0.557, p < .05); and insertion torque and ISQ values (r = 0.853, p < .001). CONCLUSION CT is a useful tool to assess bone quantity and quality in implant recipient sites, and bone density has a prevailing effect on implant stability at placement.

Two Alternative Surgical Techniques for Enhancing Primary Implant Stability in the Posterior Maxilla: A Clinical Study Including Bone Density, Insertion Torque, and Resonance Frequency Analysis Data

BACKGROUND The primary stability of dental implants associated with resistance to micromotion during healing is affected by surgical technique and implant design, which are important especially in the soft bone, where implant failures are more likely. PURPOSES This study was designed to compare the parameters associated with implant insertion using two different methods of enhancing implant primary stability and to identify any relationship between these parameters at implant insertion. MATERIALS AND METHODS A total of 60 implants were placed in the maxillary posterior regions of 22 patients. The bone densities at the implant sites were recorded using a computerized tomography machine in Hounsfield unit (HU). The maximum insertion torque data were recorded with the Osseocare (Nobel Biocare AB, Göteborg, Sweden) equipment, while resonance frequency analysis (RFA) measurements were taken using an Osstell (Integration Diagnostics AB, Göteborg, Sweden) machine at implant surgery. Comparisons including HU, Ncm, and implant stability quotient were made between two control groups (C1 and C2), and corresponding four test groups (T1-T4) using thinner drills to enhance primary implant stability. RESULTS Two implants were lost, meaning an overall implant survival rate of 96.6% after 3 +/- 1 years. When compared to control groups, significantly higher mean maximum insertion torque and RFA values were found for corresponding test groups. In addition, strong correlations were observed between the bone density and insertion torque, and implant stability values at implant placement. CONCLUSION The results of this study suggest that using thinner drills for implant placement in the maxillary posterior region where bone quality is poor may improve the primary implant stability, which helps clinicians to obtain higher implant survival rates.

Should edentulous patients be constrained to removable complete dentures? The use of dental implants to improve the quality of life for edentulous patients.

BACKGROUND Nowadays, there is some speculation among dental educators that the need for complete dentures will significantly decrease in the future and that training in their provision should be removed from the dental curriculum. OBJECTIVE To sensitise the reader to the functional shortcomings of complete denture therapy in the edentulous patient and present restorative options including implants to improve edentulous quality of life in these patients. METHODS Information retrieval followed a systematic approach using PubMed. English articles published from 1964 to 2008, in which the masticatory performance of patients with implant-supported dentures was assessed by objective methods and compared with performance with conventional dentures, were included. RESULTS National epidemiological survey data suggested that the adult population in need of one or two complete dentures will increase from 35.4 million adults in 2000 to 37.9 million adults in 2020. Clinical studies have showed that the ratings of general satisfaction were significantly better in the patients treated with implant overdentures post-delivery compared with the complete denture users. In addition, the implant group gave significantly higher ratings on comfort, stability and ability to chew. Furthermore, patients who received mandibular implant overdentures had significantly fewer oral health-related quality of life problems than did the conventional group. CONCLUSION Implant-supported dentures including either complete overdentures or a hybrid prosthesis significantly improve the quality of life for edentulous patients compared with conventional removable complete dentures. Therefore, the contemporary dental practitioner should consider other options as well as conventional removable complete dentures to restore edentulous patients.

Determination of Bone Quality of 372 Implant Recipient Sites Using Hounsfield Unit from Computerized Tomography: A Clinical Study

BACKGROUND The type and architecture of bone are very important factors in the successful implant treatment, and it is manifested that higher implant failure is more likely in the poorer quality of bone. Conventional bone classifications have recently been questioned because they are subjective and retrospective. PURPOSE This clinical study aimed to determine the variations of the bone density in dental implant recipient sites using computerized tomography (CT). MATERIALS AND METHODS The study group comprised of randomly selected 140 patients with 372 implant sites. Recipient sites for implant placement were determined based on CT data using implant planning StentCad software (Media Lab Software, La Spezia, Italy). The mean bone density values in Hounsfield unit (HU) of the simulated implant areas were recorded using the StentCad software. RESULTS The HU values ranged from 68 to 1,603 HU. It was found that mean bone density values were 927 +/- 237, 721 +/- 291, 708 +/- 277, and 505 +/- 274 HU in the anterior mandible, posterior mandible, anterior maxilla, and posterior maxilla, respectively. CONCLUSION Preoperative CT examination may be a useful method for determining the bone density of recipient areas before implant placement, and this valuable information about bone quality helps clinicians to make better treatment planning regarding the implant positions.

Clinical study on the insertion torque and wireless resonance frequency analysis in the assessment of torque capacity and stability of self-tapping dental implants

Resonance frequency (RF) analysis is a non-invasive, objective and sensitive technique developed for implantology where it measures the stability of the implant in osteotomy site. Although many studies were performed by the previous electronic version of RF analyzer, a very limited number of studies were carried out with the new magnetic wireless version. The aim of the study was to evaluate the relation between insertion torques, primary and secondary stability of self-tapping tapered implant systems. Thirteen subjects were treated with 42 endosseous implants using two-stage surgical procedure. The maximal insertion torque values were recorded prior to RF analysis during surgery. Six months after surgery, the secondary stability values were measured by the RF analysis. The average maximal insertion torque and primary and secondary magnetic RF values were 33 +/- 11 N cm and 66 +/- 12 ISQ and 71.9 +/- 6 ISQ for 42 implants respectively. The correlation between insertion torque and RF values were indicated to be statistically significant (P < 0.01). Significantly higher maximal insertion torque, and primary and secondary magnetic RF values were achieved in mandibular sites compared with maxillary areas (P < 0.01). No significant differences were measured for all parameters when both systems were compared with each other (P > 0.05). There was a strong correlation between the insertion torque, primary and secondary magnetic RF values of self-tapping tapered endosseous implant used. Further studies are needed to understand the impact of the wireless magnetic RF analysis technique in clinics.

Influence of Defect Depth on Resonance Frequency Analysis and Insertion Torque Values for Implants Placed in Fresh Extraction Sockets: A Human Cadaver Study

BACKGROUND Clinical studies show promising outcomes with implants inserted at the time of extraction. However, this often results in an initial bone defect at the marginal region which preferably should heal for an optimal function. Therefore, monitoring of these implants is vital. PURPOSES The aims of this study were to determine the initial stability of implants placed into fresh extraction sockets, and to explore the correlations between the peri-implant bone levels and implant stability parameters. MATERIALS AND METHODS Six human cadaver mandibles including all natural teeth were selected for this study. All natural teeth were gently extracted, and 84 implants were immediately placed into fresh extraction sockets with five different implant depths. The maximum insertion torque values were recorded, and primary implant stability measurements were performed by means of resonance frequency analysis (RFA). The vertical distance between implant/abutment junction and the first bone-implant contact was recorded using a periodontal probe. RESULTS It was found that the insertion torque and RFA were 28.9 +/- 7 Ncm and 65.6 +/- 9 implant stability quotient (ISQ), respectively, for 420 measurements from all 84 implants. Statistically significant correlation was found between insertion torque and ISQ values (r = 0.86; p < .001) for all implants. Both insertion torque and ISQ values dramatically decreased when the amount of peri-implant vertical bone defect increased. CONCLUSION The results of this study demonstrated a linear relationship between peri-implant vertical bone defect depth and RFA value. It is proposed that the RFA method is sensitive to detect changes of the marginal bone level and may be used to monitor healing of peri-implant bone defects.

One-year clinical outcome of dental implants placed in patients with type 2 diabetes mellitus: a case series.

Purpose:Diabetes mellitus is a prevalent medical disorder. It is often accompanied with systemic adverse sequelae, such as wound healing alterations, which may affect osseointegration of dental implants. The use of dental implants in patients with diabetes mellitus remains controversial because altered bone healing around implants has been reported. The purpose of this study was to present 1-year clinical outcomes of 23 implants placed in 10 patients with well-, or moderately well, controlled type 2 diabetes mellitus. Materials:All implants were uneventfully placed in the mandible or maxilla. Three different types of definitive implant-supported prostheses, cement- or screw-retained fixed dental prostheses, and overdentures were delivered to the patients. Results:At 1-year follow-up recall, no implants were lost, and 0.3 ± 0.2 mm marginal bone loss was noted. No periapical radiolucencies, no bleeding on probing, or pathologic probing depth were recorded at these recalls. Conclusion:This clinical report supports the use of dental implants in patients with well-, or moderately well, controlled type 2 diabetes mellitus as a dental treatment modality. No evidence of diminished clinical success or significant complication related to implant treatment was found for this patient population.

Accuracy of three different types of stereolithographic surgical guide in implant placement: An in vitro study

STATEMENT OF PROBLEM Precise treatment planning before implant surgery is necessary to identify vital structures and to ensure a predictable restorative outcome. PURPOSE The purpose of this study was to compare the accuracy of implant placement by using 3 different types of surgical guide: bone-supported, tooth-supported, and mucosa-supported. MATERIAL AND METHODS Thirty acrylic resin mandibles were fabricated with stereolithography (SLA) based on data from the cone beam computerized tomography (CBCT) scan of an edentulous patient. Ten of the mandibles were modified digitally before fabrication with the addition of 4 teeth, and 10 of the mandibles were modified after fabrication with soft acrylic resin to simulate mucosa. Each acrylic resin mandible had 5 implants virtually planned in a 3-D software program. A total of 150 implants were planned and placed by using SLA guides. Presurgical and postsurgical CBCT scans were superimposed to compare the virtual implant placement with the actual implant placement. For statistical analyses, a linear mixed models approach and t-test with the 2-sided alpha level set at .016 were used. All reported P values were adjusted by the Dunn-Sidak method to control the Type I error rate across multiple pairwise comparisons. RESULTS The mean angular deviation of the long axis between the planned and placed implants was 2.2 ±1.2 degrees; the mean deviations in linear distance between the planned and placed implants were 1.18 ±0.42 mm at the implant neck and 1.44 ±0.67 mm at the implant apex for all 150 implants. After the superimposition procedure, the angular deviation of the placed implants was 2.26 ±1.30 degrees with the tooth-supported, 2.17 ±1.02 degrees with the bone-supported, and 2.29 ±1.28 degrees with the mucosa-supported SLA guide. The mean deviations in linear distance between the planned and placed implants at the neck and apex were 1.00 ±0.33 mm and 1.15 ±0.42 mm for the tooth-supported guides; 1.08 ±0.33 mm and 1.53 ±0.90 mm for the bone-supported guides; and 1.47 ±0.43 mm and 1.65 ±0.48 mm for the mucosa-supported SLA surgical guides. CONCLUSIONS The results of this study show that stereolithographic surgical guides may be reliable in implant placement and that: 1) there was no statistically significant difference among the 3 types of guide when comparing angular deviation and 2) mucosa-supported guides were less accurate than both tooth-supported and bone-supported guides for linear deviation at the implant neck and apex.