Radiological Evaluation of the Dimensions of Lower Molar Alveoli.

PURPOSE: The aim of the present radiological study was to analyze the alveolar bone morphology of the lower molars in physiological conditions. The main goal is to describe the bone anatomy of a hypothetically postextractive site in lower molar area. MATERIALS AND METHODS: Computed tomography scans of 100 patients were examined. Axial, paraxial, and Panorex sections were analyzed using a dedicated software. Precise reference points were encoded to make the bone measurements clear and repeatable. RESULTS: The total number of dental sites examined was 235. The mean available bone height was 13.32 ± 3.23 mm in first molars and 11.76 ± 2.82 mm in second molars. The inter-radicular septum was present in 86% out of cases in first molar sites and in 52% in second molar sites. The lingual cortex mean width, at the most coronal point, measured 1.41 ± 0.52 mm in first molar alveoli and 1.67 ± 0.66 mm in second molar alveoli. CONCLUSIONS: Proper clinical conditions, for scheduling a postextraction immediate implant placement surgery, involve the presence of 4 bone walls showing and sufficient height and width. The accurate knowledge of alveolus bone morphology of mandibular molars, prior extraction, could be an important guide to avoid potential failures due to nonideal anatomical features to fixture stabilization.

Anatomical and Radiologic Evaluation of the Dimensions of Upper Molar Alveoli.

PURPOSE: The aim of the present study was to analyze the alveolar bone morphology of the upper first and second molars. This analysis aims to evaluate the morphology of a hypothetical postextractive site in the upper molar area to diagnose the possibility of immediate postextraction implant placement. MATERIALS AND METHODS: Cone-beam CT scans of 100 patients were examined. The measurements were made using a dedicated 3D software. Reference points were identified to allow clear and repeatable measurements. RESULTS: The mean available height was 7.43 ± 3.40 mm for the upper first molars and 7.07 ± 3.09 mm for the upper second molars. The interradicular septum was present in first molars in 74% of cases and 44% of cases in upper second molars. CONCLUSIONS: In most cases, the alveolar sites of the upper first and second molars do not present ideal conditions for immediate implant insertion in a correct position. The primary stabilization of a standard-sized dental implant is often difficult because of the minimum apical bone available. In particular, the interradicular septum, which often represents the ideal fixture position, is rarely adequately represented. Preoperative cone-beam scan and the knowledge of anatomical measurements from the present analysis are fundamental before planning immediate postextractive implants in the upper molar area.

A New Highly Hydrophilic Electrochemical Implant Titanium Surface: A Histological and Biomechanical In Vivo Study.

PURPOSE: The aim was to compare the osseointegration degree and secondary implant stability between implants with different surface treatments. MATERIALS AND METHODS: A novel electrochemical treatment was applied to modify the sandblasted and acid-etched surface (SLA) to obtain the new hydrophilic Feeling (FEL) surface presenting a highly soluble and homogenous film made of calcium and phosphorus nanocrystals. Twenty 3.8 × 10-mm dynamix implants (Cortex) were inserted in sheep iliac crests. Sheep were killed after 2 months. Bone-to-implant contact percentage (%BIC) and biomechanical parameters, such as implant stability quotient (ISQ) and value of actual micromotion (VAM), were evaluated for each implants. RESULTS: No implant failures were observed. Implants of test group showed %BIC value 30% higher in respect with control group (P = 0.001). No statistical differences were detected between the 2 groups in VAM and ISQ values. CONCLUSION: Both surface treatments were highly osteoconductive because they were able to significantly increase the bone density onto implant surface in respect with that in which they were inserted (D4 bone density). The hydrophilic FEL surface demonstrated an increase of about 216% in BIC in respect with host bone density and an additional 30% more in respect with SLA surface. Faster osseointegration process is desirable in case of early implant loading protocol.

Impact of Second Stage Surgery on Bone Remodeling Around New Hybrid Titanium Implants: A Prospective Clinical Study in Humans.

OBJECTIVE: The present prospective study aimed to more precisely identify the time points of bone changes around hybrid titanium implants up to 30 months of follow-up. MATERIALS AND METHODS: Twelve hybrid T3 implants (Biomet 3i) were placed in 9 healthy patients with the 2-stage surgical approach. Standardized digital Rx were taken at implant insertion (T0); healing-abutment connection after 3.1 ± 0.2 weeks (TX); loading stage after 7.5 ± 0.6 weeks (T1); after 12 months (T2); and after 30 months (T3) of functional loading. The marginal bone loss was digitally measured. RESULTS: The mean marginal bone loss was 0.76 ± 0.37 mm after 30 months. More than 60% (0.42 ± 0.29 mm) of the bone loss took place at healing-abutment connection (TX-T1). No statistically significant bone loss was found between T1-T2 and T2-T3, after 12 and 30 months, respectively. Approximately 40% of bone loss (0.34 mm) was noted between T1 and T3 (P < 0.05), which corresponds to the loading period. CONCLUSIONS: The implant-oral environment connection represents a critical step point in crestal bone loss. The amount of marginal bone loss, measured after 30 months of loading (T1-T3), was much less than that reported in the literature, showing that correct loading has a minor impact on the periimplant bone remodeling as compared to surgical implant reopening.

Validation of value of actual micromotion as a direct measure of implant micromobility after healing (secondary implant stability). An in vivo histologic and biomechanical study.

OBJECTIVES: The osseointegration process replaces the surgically damaged bone with newly formed bone in contact to the implant surface. This involves some loss of primary stability, which will continue until new bone is formed providing a new stability, known as "secondary stability." A direct measurement of secondary implant stability appears fundamental to determine the period and modalities for implant loading. The aim of this study was to validate the measurement of the implant micromotion to test secondary implant stability. MATERIALS AND METHODS: Twenty-four 3.8 × 11.5 mm implants (Dynamix, Cortex, Shlomi, Israel) were inserted in sheep iliac crests. The animals were sacrificed after 2 months, and the freshly retrieved bone blocks were immediately fixed on a customized device to calculate the value of actual micromotion (VAM) according to a previously described technique. Implant stability quotient (ISQ) values, reverse torque value (RTV), %bone-to-implant contact (%BIC), bone volume percentage (%BV) and crestal bone loss (CBL) were also calculated for each implant. Statistical correlations between VAM and the other parameters were calculated. RESULTS: Data correlation analysis between the examined parameters showed that VAM significantly correlates (P < 0.05) to RTV, %BIC, ISQ and CBL. CONCLUSIONS: As VAM showed to be statistical correlated to the other parameters of osseointegration, it may be used to clinically check the amount of implant osseointegration, secondary stability and CBL. Future studies are needed to confirm these results moreover. An instrument to measure VAM in the oral cavity still needs to be developed.

New Osseodensification Implant Site Preparation Method to Increase Bone Density in Low-Density Bone: In Vivo Evaluation in Sheep.

PURPOSE: The aim of this study was to evaluate a new surgical technique for implant site preparation that could allow to enhance bone density, ridge width, and implant secondary stability. MATERIALS AND METHODS: The edges of the iliac crests of 2 sheep were exposed and ten 3.8 × 10-mm Dynamix implants (Cortex) were inserted in the left sides using the conventional drilling method (control group). Ten 5 × 10-mm Dynamix implants (Cortex) were inserted in the right sides (test group) using the osseodensification procedure (Versah). After 2 months of healing, the sheep were killed, and biomechanical and histological examinations were performed. RESULTS: No implant failures were observed after 2 months of healing. A significant increase of ridge width and bone volume percentage (%BV) (approximately 30% higher) was detected in the test group. Significantly better removal torque values and micromotion under lateral forces (value of actual micromotion) were recorded for the test group in respect with the control group. CONCLUSION: Osseodensification technique used in the present in vivo study was demonstrated to be able to increase the %BV around dental implants inserted in low-density bone in respect to conventional implant drilling techniques, which may play a role in enhancing implant stability and reduce micromotion.

Laser-Treated Titanium Implants: An In Vivo Histomorphometric and Biomechanical Analysis.

PURPOSE: The aim of the present histological and biomechanical analysis was to compare, in vivo, the strength and quality of osseointegration between a laser-treated implant surface and a standard machined surface. MATERIAL AND METHODS: Customized titanium implants, having 2 different surfaces, were used. Implants were longitudinally split in the 2 surfaces: one side was laser treated and the opposite one had a machined surface. Eight implants were inserted in the iliac crest of 2 sheep: 4 with a split laser and machined surfaces, 2 with a completely laser-treated surface, and 2 with fully machined surfaces. The animals were killed 8 weeks after the placement of implants. The histomorphometric and biomechanical parameters calculated for each surface were the bone-implant contact (%BIC) and the reverse torque value (RTV) RESULTS:: The RTV of the laser-treated implants were about 3-fold higher than that of the machined implants. The histomorphometric results showed a significant difference of %BIC around 30% between the laser surfaces compared to the machined ones. CONCLUSIONS: The present study showed that laser surface treatment induces better osteointegration than machined surface. The laser-treated surface seems to be able to increase the osseointegration amount in respect to the machined implants.

The Effects of High Insertion Torque Versus Low Insertion Torque on Marginal Bone Resorption and Implant Failure Rates: A Systematic Review With Meta-Analyses.

OBJECTIVES: The aim was to analyze the data about the effects on marginal bone resorption and implant failure rates between implants inserted with high or low insertion torque values. MATERIALS AND METHODS: A systematic literature search until July 2015 was conducted. Data were summarized qualitatively in descriptive tables and quantitatively by performing random effects meta-analyses of effect sizes (ESs) for bone resorption and bone-to-implant contact (BIC) and relative risks (RRs) for implant failures. Risk of bias assessments were performed using the Cochrane tool for human studies and the SYRCLE's tool for animal studies. RESULTS: Four studies in humans and 6 quasirandomized animal studies were included. A total of 591 implants were evaluated qualitatively: 348 installed with high insertion torque (>25 Ncm, up to 176 Ncm) and 243 implants inserted with low torque values (<30-35 Ncm). No significant differences were detected for bone resorption (ES, 0.13; 95% confidence interval [CI], -0.12 to 0.38 in human studies; ES predictive interval from 35.03 to 34.50 in animal studies), implant failure (RR, 0.39; 95% CI, 0.01-20.77 in human studies; RR, 2.05; 95% CI, 0.19-21.71 in animal studies), or BIC (ES predictive interval from -3.84 to 5.13 in animal studies). CONCLUSION: The current review indicated that there is no significant difference in marginal bone resorption and implant failure rate between implants inserted with high or low insertion torque values.

Effect of Implant Thread Geometry on Secondary Stability, Bone Density, and Bone-to-Implant Contact: A Biomechanical and Histological Analysis.

PURPOSE: This study evaluated the effect of 2 different thread designs on secondary stability (micromotion) and osseointegration rate in dense and cancellous bones. MATERIALS AND METHODS: Forty large threaded and 40 small threaded implants (Cortex) were placed in low- (iliac crest) and high-density (mandible) bone of sheep. Two months later, micromobility tests and histological analysis were performed to measure secondary stability, osseointegration (bone-to-implant contact percentage [%BIC]), and bone density (bone volume percentage [%BV]). The value of actual micromotion of implant is introduced as a new parameter to evaluate secondary stability. RESULTS: Large threaded implants showed significantly higher %BIC and %BV than small threaded implants in low-density bone and statistically higher secondary stability in cancellous and cortical bones. CONCLUSIONS: Implants in dense bone reach higher secondary stability than those in cancellous bone, despite the lower %BIC. Implant geometry and bone density play a key role in secondary stability. Large thread design improves bone anchorage mechanically and histologically as compared with small threaded implants.

Effect of temperature on the dental implant osseointegration development in low-density bone: an in vivo histological evaluation.

OBJECTIVES: To make an in vivo evaluation of the effects of 2 different bone temperatures, on the development of implant osseointegration, in low-density bone. MATERIALS AND METHODS: Fifteen implant osteotomic sites were prepared in the iliac crests of sheep. Before the implant insertion, 5 sites were heated to 50°C for 1 minute, 5 sites to 60°C for 1 minute, and 5 sites were not overheated. Fifteen titanium dental implants (Cortex, Israel) were inserted. After a healing period of 2 months, the histomorphometric parameters calculated for each implant were the Bone-Implant Contact percentage (%BIC) and the infrabony pocket depth. Unpaired t test was applied to find statistical differences between groups. RESULTS: No implants failed. Statistical significant differences in %BIC and periimplant bone loss were found between the 60°C group and control group. No significant differences were found between the 50°C group and control group, although bone suffering signs were present. CONCLUSION: An osteotomic site overheating up to 60°C for 1 minute in low-density bone, before implant insertion, did not lead to implant failure, but it induced significant crestal bone loss during healing and lower %BIC.

Insufficient irrigation induces peri-implant bone resorption: an in vivo histologic analysis in sheep.

OBJECTIVES: To measure in vivo impact of dense bone overheating on implant osseointegration and peri-implant bone resorption comparing different bur irrigation methods vs. no irrigation. MATERIALS AND METHODS: Twenty TI-bone implants were inserted in the inferior edge of mandibles of sheep. Different cooling procedures were used in each group: no irrigation (group A), only internal bur irrigation (group B), both internal and external irrigation (group C), and external irrigation (group D). The histomorphometric parameters calculated for each implant were as follows: %cortical bone-implant contact (%CBIC) and %cortical bone volume (%CBV). Friedman's test was applied to test the statistical differences. RESULTS: In group A, we found a huge resorption of cortical bone with %CBIC and %CBV values extremely low. Groups B and C showed mean %CBIC and %BV values higher than other groups The mean %CBV value was significantly different when comparing group B and group C vs. group A (P < 0.05). Significant differences in %CBIC were found also between group C and group A (P < 0.05). CONCLUSIONS: Thermal injury, due to insufficient irrigation, of hard bone caused massive resorption of the cortical bone and implant failure. Drilling procedures on hard bone need an adequate cooling supply because the bone matrix overheating may induce complete resorption of dense bone around implants. Internal-external irrigation and only internal irrigation showed to be more efficient than other types of cooling methods in preventing bone resorption around implants.

Effect of 50 to 60°C heating on osseointegration of dental implants in dense bone: an in vivo histological study.

OBJECTIVES: To evaluate, in vivo, the effects of bone temperatures increased up to 60°C introduced before implant insertion on titanium implant osseointegration. MATERIALS AND METHODS: Twenty-four acid etched and sandblasted implants (Cortex Dental Implants) were inserted in the inferior edge of sheep mandibles. Osteotomic sites were randomly divided into 3 groups before inserting the implant. In test 1 group and in test 2 group, implant sites were overheated, respectively, up to 50°C for 1 minute and 60°C for 1 minute, with an electronic controlled probe of 3 mm in diameter and 10 mm in length. Osteotomic sites in control group were not overheated. Implants were inserted according to standard procedures. After 2 months healing, % bone implant contact (%BIC) and infrabony pockets' depth were measured. Unpaired t test was applied to find statistical differences between groups. RESULTS: No implant failure occurred. No statistical significant difference in %BIC was found among groups. Histological analysis showed that mean infrabony pockets were statistically deeper in 60°C group than in other groups. CONCLUSIONS: Bone temperature up to 60°C for 1 minute does not seem to significantly impair titanium dental implant osseointegration. Bone damage signs evident in the 60°C group suggest that careful drilling procedure with sufficient irrigation is necessary to avoid periimplant infrabony pockets' formation. More in vivo evaluations are needed to identify what is the value of bone temperature increase for irreversible inhibition of implant osseointegration.

Comparison of Different Techniques in Post-Extractive Socket Regeneration Using Autologous Tooth Graft: Histological and Clinical Outcomes.

OBJECTIVE: Post-extractive socket grafting techniques reduce alveolar ridge dimensional changes. Numerous graft materials have been suggested and a growing interest in tooth material has been observed as a valuable alternative to synthetic biomaterials or xenografts. Furthermore, different clinical procedures have been proposed for the wound closure of the post-extractive site. This study aims to compare histological and clinical outcomes of two different surgical techniques to seal the post-extractive site with the use of autologous demineralized extracted tooth as graft material. MATERIALS AND METHODS: Sixteen post-extractive socket without buccal and/or palatal bone walls, in sixteen healthy patients, were grafted with the autologous tooth material treated by the new Tooth Transformer device (Tooth Transformer, Milan, Italy). Alveolar socket preservation procedures were performed without flap elevation. Patients were randomly subdivided into two equal groups according to the site closure technique. In group A, the pedunculate tissue was used, while in group B ice cone technique. A bone samples were collected in each site after 4 months for histological analysis. RESULTS: No significant clinical differences among the different sealing techniques were observed. In both groups, the site was filled by new bone formation after 4 months of healing. The histological analysis revealed 46.1 ± 8.07% of bone volume, 9.2 ± 9.46% of residual graft, and 35.2 ± 12.36% of vital bone in group A, while group B shows 41.22 ± 5.88% of bone volume, 7.94 ± 7.54% of residual graft, and 31.7 ± 7.52% new bone. No statistical differences were detected (p > 0.05). CONCLUSION: Further studies with a large number of patients, and different observation periods will be needed to confirm the results of this pilot study; however, the interesting data obtained have shown how these techniques, mixed with the autologous dentin derived graft material, seem to promote bone regeneration and reduce physiological bone resorption during alveolar socket preservation treatments.

Single-drill implant induces bone corticalization during submerged healing: an in vivo pilot study.

PURPOSE: The aim of the present paper is to evaluate a simplified implant site preparation technique to preserve bone bulk and enhance osseointegration using a new conical self-tapping implant in cancellous bone. MATERIALS AND METHODS: Ten Expander® 3.8 × 10 mm implants (NoDrill®, Milano, Italy) were inserted in the right side (test group) of sheep's iliac crest using only the pilot drill 1.8 mm in diameter. Ten 3.8 × 10 mm Dynamix® implants (Cortex, Shlomi, Israel) were inserted in the right side (control group) of the same animals following the drilling protocol provided by the manufacturer. Histological, histomorphometric, and biomechanical analyses were performed after 2 months. RESULTS: Implants that belonged to the test group showed a %BIC of 70.91 ± 7.95 while the control group implants had a %BIC value of 49.33 ± 10.73. The %BV was 41.83 ± 6.30 in the test group and 29.61 ± 5.05 in the control group. These differences were statistically significant. A phenomenon of osseocorticalization, characterized by more bone volume percentage around implant area than in the neighboring areas, caused by implant threads geometry, was evident in the test group. CONCLUSION: This surgical protocol allows to insert an innovative fixture geometry in low-density bone using only a pilot drill. This technique demonstrated many clinical and histological advantages with respect to standard implant drilling procedures and classical implant geometry.

Nonsurgical Management of Peri-implant Bone Loss Induced by Residual Cement: Retrospective Analysis of Six Cases.

This report presents six consecutive cases of peri-implantitis associated with residual methacrylate cement. The cases responded to cement removal and disinfection procedures. Six patients, each presenting one methacrylate cement-retained implant restoration and showing peri-implant inflammation and bone loss, were treated. All the cases were negative for bleeding on probing after 6 weeks, and this was maintained at 1 year of follow-up from nonsurgical therapy and crown refixation with alternative and resorbable cement. The treatment effectively solved the inflammation and led to complete restoration ad integrum, as evaluated clinically and radiographically, after 1 year.

Correlation Between Implant Geometry, Implant Surface, Insertion Torque, and Primary Stability: In Vitro Biomechanical Analysis.

PURPOSE: Primary implant stability represents the first step for successful osseointegration. The knowledge of the correlation between host bone density, insertion torque, and implant macrogeometry seems to be fundamental to achieve sufficient primary implant bone fixation in each clinical situation. The purpose of this study was to measure, in vitro, the impact of dental implant macrogeometry and insertion torque values on primary stability in relation to different bone densities, representing both the human mandible and maxilla. MATERIALS AND METHODS: One hundred twenty 3.8 ± 11-mm commercial dental implants were used. Forty implants had small threads with a machined neck, 40 implants had small threads with a microthreaded neck, and the last 40 implants had large threads with a reverse neck design. Fresh bovine ribs, representing a medium-dense bone density (D2-D3), and fresh ovine iliac crest, representing a soft bone density (D4), were used. Insertion torque and micromobility under lateral force data were recorded for each implant. RESULTS: In the medium-dense bone type, the reverse neck implant design showed less primary implant stability than the conventional straight implant neck. In soft bone, both implants with the large thread design and microthreaded neck implants showed better implant stability than the implant with a small thread design with a straight machined neck. Implants with large and self-cutting threads showed significantly (P < .05) lower micromobility values than other implants in postextractive sites in low-density bone. CONCLUSION: Implant geometries and bone density are the main factors involved in the degree of primary implant stability. Large-thread implant designs are highly desirable in cases of poor bone quality. Each implant geometry generates an insertion torque value, which is correlated to the stability of that specific implant in a specific bone quality, but the insertion torque is not an objective value to compare primary stability between different implant types.

A retrospective study of clinical and radiologic outcomes of 69 consecutive maxillary sinus augmentations associated with functional endoscopic sinus surgery.

PURPOSE: The aim of this clinical investigation was to evaluate the clinical and radiologic outcomes of a single-step surgical procedure that includes functional endoscopic sinus surgery (FESS) and maxillary sinus elevation by the lateral window approach in patients with reversible contraindications to sinus elevation. MATERIALS AND METHODS: Thirty-eight patients with insufficient bone height in the posterior maxilla caused by pneumatization of the sinus and with reversible ear-nose-throat (ENT) contraindications to sinus elevation were recruited for this investigation between January 2010 and January 2012. All patients were treated in a single session under general anesthesia for a total of 69 consecutive sinus augmentations. FESS was performed by an ENT specialist, and an oral surgeon carried out sinus elevation through the lateral window approach. Particulate xenograft was used beneath the sinus membrane. Intraoperative and postoperative complications (eg, membrane tears, rhinosinusitis, graft infection or loss) were reported. Nasal endoscopies were performed at 7, 14, and 30 days and 3 months after treatment. After a healing period of 6 months, 137 implants were inserted. Computed tomography scans were performed after 6 months and 1 year. RESULTS: Intraoperative membrane perforation occurred in only one case. No implant failures were recorded during the follow-up period. Radiologic and clinical findings showed the resolution of ENT disease and good bone graft integration after 1 year. A relapse of mucosal thickening observed in some patients did not influence the graft healing. CONCLUSION: Preliminary rhinosinusal evaluation by an ENT specialist and computed tomography of the ostiomeatal complex are necessary in patients needing maxillary sinus elevation. A single-step approach to FESS and sinus elevation is a predictable technique to manage patients with ENT reversible contraindications to sinus elevation.