Emre Mumcu

Influence of surgical technique, implant shape and diameter on the primary stability in cancellous bone

Achievement of primary stability during surgical placement of dental implants is one of the most important factors for successful osseointegration depending on various anatomical, surgical and implant-related factors. Resonance frequency analysis (RFA) has been shown as a non-invasive and objective technique for measuring the stability of implants. The aim of this study was to evaluate the effect of some surgical and implant-related factors in enhancing primary stability and to estimate a correlation between RFA and insertion torque (IT) in proximal regions of cow ribs representing cancellous bone. Fifteen implant beds were prepared in the most proximal region of six fresh cow ribs. Ninety implants with three different shapes and two different diameters were placed with two different surgical techniques, and the primary stability was compared using RFA and IT. Significantly higher RFA and IT values were achieved when under-dimensioned drilling was used as the surgical method (P<0·01); significantly higher IT values were obtained with the use of wider implants (P<0·01) and partially conical Astra Tech implants showed the highest IT values (P<0·01). When all the implants were considered, significant correlations between the IT and RFA values were noted (%40·6, P<0·05). Partially conical implants with a wide diameter to be placed with the modified surgical technique proposed appear to be useful in enhancing the primary stability in cancellous bone.

Micro push-out bond strengths of 2 fiber post types luted using different adhesive strategies

OBJECTIVE The objective of this study was to evaluate the push-out bond strengths of carbon and glass fiber posts adhesively luted with Panavia F 2.0 and RelyX Unicem luting cements, as well as a modified application procedure using RelyX Unicem cement in combination with a single-bottle total-etch adhesive in 3 segments of teeth. STUDY DESIGN Sixty single-rooted human maxillary central incisors and canines were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were divided into 2 fiber-post groups, and then divided into 3 subgroups of 10 specimens each to test different luting strategies. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. RESULTS Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05). In all root sections, the push-out bond strength values of glass fiber posts were significantly higher than that of carbon fiber posts (P < .05). Moreover, the highest push-out bond strengths were measured for Panavia F 2.0 and RelyX Unicem cements. These values were significantly higher than that of modified application procedure in the medium section for both glass- and carbon-fiber posts, and in the apical root sections only for glass-fiber post (P < .05). In each region, the modified application procedure showed the lowest bond strength values. Adhesive failure between dentin and cement was the most frequent type of failure. CONCLUSIONS In all root segments, the glass fiber post provided significantly increased post retention compared with the carbon fiber post, regardless of the luting strategy used.

Evaluation of possible prognostic factors for the success, survival, and failure of dental implants.

Purpose:To analyze the prognostic factors that are associated with the success, survival, and failure rates of dental implants. Material and Methods:Data including implant sizes, insertion time, implant location, and prosthetic treatment of 1656 implants have been collected, and the association of these factors with success, survival, and failure of implants was analyzed. Results:The success rate was lower for short and maxillary implants. The failure rate of maxillary implants exceeded that of mandibular implants, and the failure rate of implants that were placed in the maxillary anterior region was significantly higher than other regions. The failure rates of implants that were placed 5 years ago or more were higher than those that were placed later. Conclusions:Anterior maxilla is more critical for implant loss than other sites. Implants in the anterior mandible show better success compared with other locations, and longer implants show better success rates. The learning curve of the clinician influences survival and success rates of dental implants.

Maintenance requirements associated with mandibular implant overdentures: clinical results after first year of service.

The aim of this clinical study was to evaluate the prosthodontic maintenance requirements during the first year of service of mandibular overdentures supported by interforaminal implants and to assess the influence of attachment type, implant number, and bite force on these requirements. Fifty-nine patients treated with mandibular implant overdentures between the years 2004 and 2009 and appearing in the 12th-month recall were included in this study. The overdentures constituted 4 groups: 2 single interforaminal implants (1 group with locator and 1 group with ball attachments), 3 single interforaminal implants, 3 splinted interforaminal implants (bar), and 4 splinted interforaminal implants (bar). During the examination, prosthetic parameters such as occlusion, tissue adaptation, condition of the retentive mechanism (matrice and patrice), and the condition of the denture-bearing tissues were evaluated and recorded. No statistically significant relation was found between attachment type, bite force values, implant number, and the occurring complications except the need for relining, which was found significantly more in the ball attachments than in other attachment groups (P  =  .03). After 12 months following the overdenture insertion, there seems to be no relation between occurring complications and patient-related factors, such as maximum bite force, age, and gender, as well as factors related to the overdentures such as number and type of attachments.

Retracted: Push-out bond strengths of two fiber post types bonded with different dentin bonding agents

The aim of this study was to evaluate the regional push-out bond strengths for two fiber-reinforced post types using three different dentin bonding agents. Sixty single-rooted extracted human first premolar teeth were sectioned below the cemento-enamel junction, and the roots were endodontically treated. Following standardized post space preparations, the roots were divided into two fiber-post groups (Glassix and Carbopost), and further divided into three subgroups of 10 specimens each for the bonding systems self-etching dentin bonding agents (Clearfil SE Bond and Optibond all-in-one), and total-etching dentin bonding agent (XP Bond). A dual-cure resin luting cement (Maxcem) was then placed in the post spaces and posts were then seated into the root canals polymerized through the cervical portion. The roots were then cut into 3-mm thick sections. Push-out tests were performed at a crosshead speed of 0.5 mm/min. The data were analyzed with multivariate ANOVA (alpha = 0.05). The morphology of interface between different dentin bonding agents from the cervical sections were analyzed with SEM. Glass fiber-reinforced posts demonstrated significantly higher push-out bond strengths than carbon fiber-reinforced posts (p < 0.001). Bond strength values decreased significantly from the cervical to the apical root canal regions (p < 0.001). Self-etching dentin adhesive Clearfil SE Bond and total-etching dentin adhesive XP Bond demonstrated similar bond strengths values and this was significantly higher compared with the Optibond all-in-one in cervical root canal region. In conclusion, in all root segments, the glass fiber-reinforced posts provided significantly increased post retention than the carbon fiber-reinforced posts, regardless of the adhesive used.

Influence of platform-switching on marginal bone levels for implants with mandibular overdentures: a retrospective clinical study.

Objective:The aim of this study was to compare bone around platform switched and regular platform implants that support removable prostheses and to report of the clinical outcomes after a loading period of 36 months. Material:Fifty-one patients with a mean age of 59.39 years and 126 implants, appearing in the routine recall sessions consecutively 6, 12, 24, and 36 months after loading with mandibular overdentures, were included in the study group. Bone level measurements were obtained from images of successive radiographs, which were scanned and digitized before, and analyzed at ×20 magnification. Statistical analysis was utilized to assess the mean marginal bone level changes at 6, 12, 24, and 36 months as well as to explore the potential effect of platform switching on bone loss. Results:Although mesial and distal marginal bone loss rates differed in the 6th, 12th, and 24th month recalls between both groups, platform switching caused statistically significant lower bone loss at the 36th month on the mesial as well as distal sides. Conclusion:Platform switching appears to engender lower marginal bone loss around implants supporting removable dentures.

The Effect of Maximum Bite Force, Implant Number, and Attachment Type on Marginal Bone Loss around Implants Supporting Mandibular Overdentures: A Retrospective Study

BACKGROUND There remains controversy regarding the clinical reasons for late-implant bone loss, which is a critical factor in the long-term success of implant-supported overdentures. PURPOSE Assessment of the effect of such factors as attachment type, number of implants, gender, age, and maximum bite force (MBF) on marginal bone loss (MBL) around implants supporting mandibular overdentures. MATERIALS AND METHODS Sixty-two edentulous patients rehabilitated with two-, three-, or four-implant-supported mandibular overdentures at a university clinic between January 2006 and January 2007 and having a digital panoramic radiograph at the time of loading, were included in this study. All patients received digital panoramic radiographs, and MBL was measured by subtracting bone levels from the first radiograph. MBF was measured using a bite force transducer. RESULTS The amount of bone loss 48 months after loading was found to be unrelated to gender, age, implant number, attachment type, and splinting (p = .741, p = .953, p = .640, p = .763, p = .370, respectively). A significant correlation was observed between the MBF and the MBL of distal implants on the right side (p < .01, 79.9%) and the MBF and the MBL of distal implants on the left side (p = .011, 34.6%). CONCLUSIONS MBL around implants supporting mandibular overdentures seems not to be affected by number of implants, attachment type, age, or gender; however, MBL is affected by MBF.

The evaluation of the success of immediately placed single implants: a retrospective clinical study.

Purpose:The aim of this retrospective clinical trial was to evaluate the survival rates and the marginal bone levels of immediately placed implants in fresh extraction sockets in a period of 36 months. Patients and Methods:One hundred seventeen patients who had received 165 immediately placed implants and followed up for 36 months after loading were included in this retrospective study. Survival rate and mesial and distal marginal bone levels of all implants were determined with the measurements made on periapical radiographs at baseline and recall evaluations. Results:The results of clinical evaluation showed a survival rate of 93.94%. Ten of 165 implants failed: 7 implants in female patients indicating 90.28% survival rate and 3 male patients with 93.4% survival rate. The mean age of patients with implant failure was 60.8 years. No statistically significant differences in marginal bone levels with respect to localization, age, gender, grafting, and implant brands were noted. Grafting did not influence plaque index, gingival index, and periimplant probing depth in a statistically significant way. Conclusions:The results suggest that immediately placed single implants show acceptable survival rates and mesial and distal marginal bone levels in 36-month follow-up period.

The comparison of marginal bone loss around mandibular overdenture-supporting implants with two different attachment types in a loading period of 36 months

OBJECTIVE The aim of this study was to assess the influence of attachment types on the marginal bone loss (MBL) around dental implants supporting mandibular overdentures (OVD). BACKGROUND There are a number of in vitro studies evaluating the influence of several factors on MBL around implants. MATERIAL AND METHODS Mandibular OVD patients appearing at routine recall sessions consecutively 6, 12, 24 and 36 months after loading were included in the study group. All patients received mandibular OVD with either ball or bar attachments. Measurements were obtained from images of successive radiographs, which were scanned and digitised before, and analysed at ×20 magnification. Statistical analyses were utilised in this study to assess the mean marginal bone level changes as well as to explore the potential effect of several parameters such as the cantilever or the attachment type on bone loss. RESULTS One hundred and twenty-six implants in 51 patients with a mean age of 59.39 ± 9.99 years were evaluated. There was no statistical significant difference between the distal and mesial bone loss rates of single or splinted attachment types, whereas bone loss rates were statistically higher in cantilever situations. CONCLUSION Within the limitations of this study, gender, age and diameter of the implants do not play a role in MBL. Length of the implant is an important factor in marginal bone level maintenance. The attachment type for OVD support seems not to influence MBL, but cantilevering of the bars increases bone loss significantly.

A comparative in vitro evaluation of two different magnetic devices detecting the stability of osseo-integrated implants.

BACKGROUND AND OBJECTIVE It is unknown whether the resonance frequency analysis (RFA) measurements made by two different magnetic resonance frequency analysers are comparable. This in vitro study was designed to compare the RFA measurements made by the two magnetic resonance frequency analysers and to evaluate the intra- and interobserver reliability of the magnetic devices. MATERIAL AND METHODS Thirty-two implants were placed in four cow ribs. The RFA value of each implant was measured by five different examiners. The measurements were repeated five times, in both the buccal and mesial directions, for each implant at 2 h intervals, and the averages of registered implant stability quotient (ISQ) units were recorded as the buccal ISQ value and the mesial ISQ value for every implant. RESULTS No statistically significant differences (p>0.05) were observed between the RFA measurements made by the two magnetic devices. The intra-observer reliability of both devices was excellent, whereas the interobserver reliability of the devices was poor. CONCLUSION The results of the RFA measurements of both tested devices overlap. Although both devices show excellent intra-observer reliability, there are variations between the measurements of different examiners.