Search

PURPOSE To evaluate the incidence of ultrathin ceramic veneer fracture over a period of 36 months and the possible relationship with local- and patient-related factors. MATERIALS AND METHODS Adult patients who received ceramic veneers for improvement in smile esthetics were selected from a private practice pool. Veneers were grouped as conventional ceramic veneers (prep) or ultrathin following either a minimal preparation (min-prep) or no tooth preparation (no-prep) protocol. After veneer bonding, all patients were followed up at intervals of 6 months up to 36 months. A panel of clinical outcomes was recorded. Patient satisfaction was assessed at 36 months. RESULTS The study sample was formed by 49 patients who received a total of 194 veneers. Twelve veneers were prep, 125 were min-prep, and 57 were no-prep. Total fracture occurrence was 9.8% in 13 participants. No fractures were observed in prep veneers, while 16 out of 125 min-prep and 3 out of 57 no-prep veneers had fractures. Most fractures (13 out of 19) occurred early, within the first 12 months after bonding. Out of 194 veneers, only 1 had a catastrophic failure (0.5%), 3 had large (≥ 1 mm) chippings (1.5%), and 15 had minor (< 1 mm) chippings (7.7%). A generalized estimating equation model revealed that the odds of veneer fracture were significantly higher in men (odds ratio [OR] = 11.29), in patients who exhibited tooth wear at baseline (OR = 5.54), and in central (OR = 13.56) and lateral (OR = 10.43) incisors compared to canines and premolars. All participants indicated that they would not change to a different restorative protocol in order to have a thicker restoration and possibly less risk of fracture. CONCLUSION Ultrathin ceramic veneers are a viable cosmetic dentistry treatment option that involves minimal or no tooth preparation. However, a tendency for increased early fractures was observed in the min-prep group.

This study aimed to assess how frequently the maxilla anatomy allows for lingualized immediate implants in the central incisor region with a screw channel that has an ideal distance of 1.5 mm from the incisal margin. The effect of abutments with angle correction on case selection will also be verified. A retrospective cross-sectional study of 181 CBCT scans was carried out. Using an implant-planning software, implant placement was simulated in the lingual aspect of the socket. The location of the prospective screw channel was registered as incisal, lingual, or facial. The angle between the actual screw channel and the position of the ideal one was calculated. The effect of angle correction on allowing an ideal screw channel configuration was computed. Out of 161 eligible cases, 144 presented favorable anatomy for an immediate implant. The screw channel had an incisal position in 40 cases (28%), a lingual position in 60 cases (42%), and a facial position in 44 cases (30%). The screw channel could be placed at the planned distance from the incisal edge in 35 cases (24%). The position was unfavorable in the remaining 109 cases. In 103 of these cases, an abutment with an angled screw channel could make the conditions feasible. Within the simulated conditions, a majority of maxillary central incisors present favorable ridge anatomy for lingualized immediate implant placement. Achieving a proper location of the screw channel requires abutments with angle correction in a majority of cases.

Adequate management of the implant-supported restoration has become an important task when trying to obtain optimal esthetic outcomes. The transgingival area must be developed to maintain or influence the final appearance of the peri-implant soft tissues. Two distinct zones within the implant abutment/crown can be identified: the critical contour and the subcritical contour. Their design and subsequent alteration may impact the peri-implant soft tissue architecture, including the gingival margin level and zenith, labial alveolar profile, and gingival color. Defining these two areas helps clarify how to process soft tissue contours and may additionally improve the necessary communication with the laboratory. Since there are many protocols for placing implants, it is worthwhile to determine similarities in the contouring and macrodesign of their corresponding provisional restorations. Therefore, the purpose of this paper is to discern the general characteristics of the critical and subcritical contours for provisional restorations made for immediate and delayed implants in order to obtain guidelines for daily clinical practice.

This case report presents cone beam computed tomography (CBCT) three-dimensional (3D) assessment of the buccal bone associated with an implant.A patient who had immediate implant replacement of a maxillary incisor received a CBCT examination after 6 months. The scanned volume was then subjected to segmentation of the buccal bone associated with the implant and to its three-dimensional rendering.Virtual reconstruction allowed volumetric assessment of the buccal plate, and of the buccal marginal bone level.Creating a 3D virtual volume permits a comprehensive evaluation of the anatomical information contained in the CBCT dataset.

The aim of this study was to describe a technique for the assessment of soft tissue volumetric and profilometric changes. The technique has been applied at the alveolar contour of mild to moderate horizontal ridge defects after soft tissue augmentation at pontic sites. A quantitative three-dimensional (3D) analysis based on laser scanning was used for the measurement of volume gain and horizontal changes of alveolar profile 5 months after a subepithelial connective tissue graft using a pouch approach in five patients. All the surgical sites healed uneventfully. A mean soft tissue volume increase of 35.9 mm3 was measured 5 months after the grafting procedure. The linear measurements showed that, in the area where the augmentation was performed, the distance between the preoperative vestibular profile and the postoperative one ranged from 0.16 to 2 mm. The described quantitative measurements based on 3D laser scanning appear to be an effective method for assessment of soft tissue changes in future studies. Additionally, within the limitation of a small sample size, the present data suggest that the investigated surgical technique can be considered when corrections of mild to moderate alveolar horizontal ridge atrophies at maxillary lateral incisor edentulous gaps are necessary.

Objectives This study tested the hypothesis of no differences in resonance frequency for standardized amounts of simulated bone–implant contact around implants with different diameters. In addition, it was evaluated if resonance frequency is able to detect a difference between stable and rotation mobile (“spinning”) implants. Material and Methods Implants with diameters of 3.3, 4.1 and 4.8 mm were placed in a purposely designed metal mould where liquid polyurethane resin was then poured to obtain a simulated bone-implant specimen. By regulating the mould, it was possible to create the following simulated bone–implant contact groups: 3.3 mm (198.6 mm2); 4.1 mm (198.8 mm2); 4.8 mm (200.2 mm2); 4.8 mm (231.7 mm2); 4.8 mm (294.7 mm2). Each group included 10 specimens. After resin setting, resonance frequency was measured. On the last group, measurements were repeated after establishing implant rotational mobility. One-way ANOVA tests with post hoc comparisons, a Pearson's correlation coefficient and a t-test for repeated measurements were used to evaluate statistically significant differences. Results Implants with different diameters but with the same amount of simulated osseointegration revealed no differences in resonance frequency. On the contrary, an increase of simulated bone–implant contact resulted in significantly higher resonance frequency. A clear direct linear correlation resulted between resonance frequency and simulated bone–implant contact. Furthermore, a significant difference resulted between resonance frequency measured before and after creation of rotational mobility. Conclusions Within the conditions of this study, the secondary stability was correlated with the simulated bone–implant contact. In addition, resonance frequency was able to discern between stable and rotation mobile implants.

OBJECTIVES To evaluate, on the base of cone beam computed tomography (CBCT) fractal dimension, bone quality changes surrounding the apical portion of immediate implants placed under higher insertion torque utilizing an undersized drilling technique. MATERIALS AND METHODS Three patients were enrolled in this study. Single implants were placed into fresh extraction sockets in the anterior maxilla and provisionalized immediately. Adequate stability was ensured on all the implants by a 28.5% undersizing of the apical portion of the osteotomy. Bone quality at the most apical 1.15 mm peri-implant bone portion were measured by CBCT at placement and after 6 months. This analysis was carried out by evaluating the box counting fractal dimension of 15 consecutive CBCT slices related to the most apical part of each implant. RESULTS All the three implants were successful after an 18-month follow-up period. The mean fractal dimension at the implant apex exhibited a 3% increase 6 months following placement. CONCLUSIONS Within the limitations of an explorative study, an undersized drilling resulting in high insertion torque would seem to induce no adverse changes in radiographic bone quality after 6 months of follow-up. The most favorable entity of drilling undersizing and its effect on peri-implant bone remodeling, should be evaluated on a larger patient population.

Background: Membrane elevation in combination with implant placement without biomaterials is a rather new technique proposed for sinus lifting. Purpose: This study assessed the clinical outcome of such technique during the first year of loading. Material and Methods: Fifteen patients with a mean residual bone height of 6.2 mm were consecutively recruited for sinus lifting. After opening a replaceable bone window, the membrane was dissected from the sinus walls. A total of 28 implants were placed in the residual crest and they kept the membrane lifted upwards. After window repositioning, the flap was sutured. A 6-month healing period was allowed. Patients were re-examined after 12 months of loading. Results: All the implants survived at the end of the follow-up. The 5.5 mm mean bone reformation was significantly lower than the 8.2 mm mean membrane lift achieved after implant placement. Regeneration at the distal surface of the most posterior implants was significantly less than at other aspects. The height of membrane lift was not correlated with the amount of regenerated bone. Conclusions: All of the 28 implants placed in combination with sinus membrane elevation were stable during the first year of loading. No extra costs for biomaterial or morbidity for bone harvesting were necessary.

Background: Implant treatment in the partially edentulous maxilla is often challenging because of minimum bone volumes in distal direction. Purpose: The aim of this study was to evaluate, after 1 year of loading, the outcome of three-unit fixed partial dentures supported by two implants in the retrocanine triangle. Materials and Methods: Twenty patients with atrophic posterior maxillae participated in the study. A total of 40 implants were placed in residual bone anterior to the sinus wall and posterior to the canine. Implant angulations and lengths were chosen to match as much as possible boundaries of the available bone. After a 6-month healing period, three-unit, screw-retained, fixed partial dentures were delivered. The patients were clinically and radiographically reexamined after 1 year of loading. Results: All the implants survived at the end of the follow-up. No differences in bone level changes resulted between axial and tilted implants. No biological or mechanical complications were recorded. Conclusions: Within the limitations of this short-term study on relatively few patients, a positive outcome was seen for three-unit fixed partial dentures supported by two implants. Retrocanine placement of implants with carefully planned lengths and angulations might be an alternative to grafting procedures for restoration of atrophic posterior maxillae.

Objectives: The aim of the present study was to evaluate differences in the ultimate fracture resistance of titanium and zirconia abutments. Material and methods: Twenty titanium fixtures were embedded in 20 resin mandible section simulators to mimic osseointegrated implants in the premolar area. The embedded implants were then randomly divided into two groups. Afterwards, specimens in group A (n=10) were connected to titanium abutments (TiDesign™ 3.5/4.0, 5.5, 1.5 mm), while specimens in group B (n=10) were connected to zirconia abutments (ZirDesign™ 3.5/4.0, 5.5, 1.5 mm). Both groups were loaded to failure in a dynamometric testing machine. Fractured samples were then analyzed by scanning electron microscopy (SEM). Results: Group A showed a significantly higher fracture strength than that observed in group B. Group A failures were observed at the screw that connects the abutment with the implant while the abutment connection hexagons were plastically bent by the applied load. Group B failures were a result of abutment fractures. SEM analysis showed that in group A the screw failure was driven by crack nucleation, coalescence and propagation, while in group B, the SEM analysis of failed surfaces showed the conchoidal fracture profile characteristic of brittle materials. Conclusions: The strength of both tested systems is adequate to resist physiologic chewing forces in the premolar area. Conversely, the titanium and zirconia failure modes evaluated here occurred at unphysiological loads. In addition, because the abutments were tested witout crowns, the presented data have limited direct transfer to the clinical situation. To cite this article: Apicella D, Veltri M, Balleri P, Apicella A, Ferrari M. Influence of abutment material on fracture strength and failure modes of abutment-fixture assemblies when loaded in a bio-faithful simulation. Clin. Oral Impl. Res. 22, 2011; 182–188. doi: 10.1111/j.1600-0501.2010.01979.x

Objectives: This study investigated the correlation of quantitative ultrasound with bone quality as evaluable from implant final insertion torque. Material and methods: Implants were planned at diaphyses (group 1) and epiphyses (group 2) of 16 rabbit femurs where amplitude-dependent speed of sound (Ad-SOS) was measured. The insertion torque from 7-mm-long implants placed at planned sites was recorded. The correlation between cutting torque and Ad-SOS was evaluated using Spearman's coefficient. Results: Statistics were based on data from 15 diaphyses and 13 epiphyses. The mean insertion torque was 8.8 N cm while the mean Ad-SOS was 1710.9 m/s. A negative correlation resulted between insertion torque and Ad-SOS. Conclusions: In the rabbit bone model investigated, quantitative ultrasound correlates inversely with implant insertion torque. Although this correlation remains to be verified in humans because rabbit femur does not convincingly represents different human bone qualities, it seems that ultrasound could convey potentially useful, pre-surgical, site-specific, non-invasive information on bone mechanical characteristics therefore deserving further research efforts. To cite this article: Veltri M, Valenti R, Ceccarelli E, Balleri P, Nuti R, Ferrari M. The speed of sound correlates with implant insertion torque in rabbit bone: an in vitro experiment. Clin. Oral Impl. Res. 21, 2010; 751–755. doi: 10.1111/j.1600-0501.2009.01873.x

Objectives: The fit of implant-supported single-tooth Lava zirconia assemblies was investigated in this study. The implant–abutment interface, the interface between the metallic and the zirconia portion of the abutment and the interface between Lava abutments and copings were evaluated. The adaptation of titanium abutments to implants and Lava copings was investigated as a control. Material and methods: Twenty implants were randomly assigned and connected to Lava abutments (group 1) or titanium abutments (group 2). All specimens were subjected to scanning electron microscopy (SEM) analysis of the fixture/abutment fit. Afterwards, specimens were luted to Lava copings and subjected to a SEM evaluation of the marginal external adaptation of the abutments with the copings. Finally, the samples were embedded in resin, sectioned and subjected to SEM analysis of the following interfaces; group 1: titanium/zirconia interface (between the constitutive components of the Lava abutment) and the zirconia/zirconia interface (between the Lava abutment and the coping); group 2: the titanium/zirconia interface (between the titanium abutment and the Lava coping). Non-parametric analysis of variance and a post hoc test were used for statistical analysis. Results: Significant differences emerged in the cement thickness between titanium and zirconia components of the Lava abutments as compared with the thickness measured at the interface between Lava copings and the abutments investigated. No differences were found in cement thickness between Lava copings and the two different abutments. Conclusions: When Lava abutments are used, the most critical cement thickness is the internal interface between its titanium and zirconia components. Lava coping adaptation for both Lava and titanium abutments is within the clinical acceptable range. To cite this article: Apicella D, Veltri M, Chieffi N, Balleri P, Ferrari M. Cement thickness at implant-supported single-tooth Lava assemblies: a scanning electron microscopic investigation. Clin. Oral Impl. Res. 21, 2010; 747–750. doi: 10.1111/j.1600-0501.2009.01882.x

The purpose of this follow-up study was to measure the resonance frequency of Astra Tech TiO(2) blasted implants at second surgery, at one and 3 years of loading. Secondly, it was investigated whether resonance frequency at second surgery could discriminate between successful implants and those that will fail over a 3-year period. Fifty titanium dioxide-blasted implants in eight consecutive patients with edentulous maxillas seeking fixed rehabilitations, were included in the study at abutment connection after 6 months of healing. Resonance frequency, clinical and radiographic records were obtained at abutment connection and after one and 3 years of loading. The cumulative survival rate after 3 years was 100%. The mean resonance frequencies were 65 +/- 4.8 implant stability quotient (ISQ) at second surgery (range 50-78 ISQ), 66 +/- 3.4 ISQ after 1 year of loading (range 53-76 ISQ) and 64 +/- 3.8 ISQ after 3 years of loading (range 53-77 ISQ). No significant differences resulted between these three time points. The marginal bone level decrease of 0.6 mm between the second surgery and the 3-year follow-up was observed. One limitation of the study is that no late failures were encountered in this relatively small sample. Consequently, it was not possible to establish a cut-off ISQ for implants that, after abutment connection, would maintain their stability over a 3-year period. Nevertheless, it might be concluded that following the first year of loading the range of 53-76 ISQ describes the stability of osseointegrated Astra Tech TiO(2) blasted implants.

OBJECTIVES To evaluate the accuracy of measuring peri-implant buccal bone when using three different computed tomography devices. MATERIALS AND METHODS Sixty tissue-level or bone-level dental implants were placed in bovine ribs with either buccal bone full coverage, dehiscence or fenestration. For each site, the distance from the bone defect to the implant neck and the buccal bone thickness 1 mm apical to the crest were measured using a calliper. Subsequently, all sites were scanned in a reproducible position using a multi-slice computed tomography (CT) (Brightspeed, voxel size 0.625 mm) and two cone-beam computed tomography devices (i-CAT NG, voxel size 0.3 mm and Newtom VGi, voxel size 0.2 mm). Bone thickness was measured on images from the three systems similar to direct measurements and differences were evaluated. Factors that could influence the buccal bone identification were assessed by multiple binary logistic regression. RESULTS Buccal bone ranged from 0.1 mm to 2.75 mm in thickness and was not visible in 68%, 63% and 60% of cases when using CT, i-CAT and Newtom, respectively. For each mm of bone thickness increment, the odds of radiographic identification increased by 30.6 (P

Objectives This case series investigated by means of CBCT, buccal bone three-dimensional anatomy at delayed, two-stage implants in the maxillary incisal tooth region. Moreover, the relation between buccal bone anatomy and soft tissue aesthetics was assessed. Material and methods Twelve implants were analysed after on average 8.9 years in function. Baseline and re-evaluation photographs were assessed using the pink aesthetic score (PES). Marginal bone changes were measured from intraoral X-rays. The buccal bone volume associated with the implant and the implant surface not covered by visible buccal bone was computed on CBCT data sets. Buccal bone thickness and level were assessed, as well as the thickness of the crest distally and mesially of the implant. Changes in soft tissue forms and correlation between aesthetics and bone anatomy were calculated by nonparametric statistics. Results Buccal bone level was located 3.8 mm apical of the implant shoulder, and none of the implants had complete bone coverage. Buccal bone volume was 144.3 mm(3) , and 4.29 mm(3) in the more coronal 2 mm portion. PES did not differ at re-evaluation (9.7) and baseline (9.2). PES was directly correlated with crestal thickness mesially and distally of the implant shoulder. No other significant correlations were observed between bone anatomy and PES or buccal peri-implant health. Marginal bone gain over time was associated with greater coronal bone volume buccally and with greater buccal and marginal bone thickness, while loss was related to less or no bone. Conclusions Within present limitations, acceptable and stable aesthetics are not jeopardized by a thin or missing buccal bone.

Veltri M, Mollo A, Mantovani L, Pini P, Balleri P, Grandini S. A comparative study of Endoflare-Hero Shaper and Mtwo NiTi instruments in the preparation of curved root canals. International Endodontic Journal, 38, 610-616, 2005. Aim To analyse the shaping ability of two new NiTi rotary systems in molar curved canals. Methodology Thirty molar root canals with curva- tures from 24� to 69� were divided into two groups that were balanced in terms of curvature. The canals in one group were shaped using the Mtwo (Sweden & Martina, Padova, Italy) and the canals in the other group using the Endoflare-Hero Shaper (Micro-Mega, Besancon, France) in a modified sequence. Pre- and post-instru- mentation X-rays were taken using a radiographic platform, with a contrast medium being used to enhance canal opacity. The dentine removed at five positions along the canals, the symmetry of canal shaping and the presence of aberrations were analysed through computer-aided measurements. The instru- ment failures, the working time and the changes in working length were also recorded. The Mann-Whit- ney U-test was used for statistical analyses. Results Both systems produced uniform dentine removal and symmetrical canal shapes; there was no significant difference between the systems (P > 0.05). In the apical region, preparations were centred in the canal. A mean loss of working length of 0.55 mm for Mtwo and 0.58 mm for Endoflare-Hero Shaper was detected, with no significant differences between the instruments (P > 0.05). No aberrations were seen and no instruments separated. The mean working time was 124.4 s for the Mtwo system and 141.3 s for the Endoflare-Hero Shaper but this difference was not statistically significant (P > 0.05). Conclusion The systems tested in this study were effective in shaping curved canals in extracted teeth.

This study analyzed the abilities of ProTaper and GT Rotary files to shape the curved canals of extracted mandibular molars. Twenty mesial canals with curvatures ranging from 23 to 54 degrees (Weine analysis) were radiographically selected from a group of 58 molars. The specimens, divided into two groups, were instrumented using the two systems according to the manufacturer's guidelines. Using a radiographic platform and a contrast medium, reproducible preinstrumentation and postinstrumentation radiographs were taken. A computer analysis allowed magnification and superimposition of the images to measure the preparation asymmetry and the linear amount of dentin removal at five points along the canals and to detect canal aberrations. Instrument failures, working time, and working length changes were recorded. The dentin removal and the mean asymmetry showed no significant differences between the two systems. Neither aberrations nor significant changes in working length resulted, but two instruments separated in each group. Working time was shorter for ProTaper files (p < 0.05).

This study aimed at investigating the effects of titanium implants and different configurations of full- arch prostheses on the biomechanics of edentulous mandibles. Reverse engineered, composite, anisotropic, edentulous mandibles made of a poly(methylmethacrylate) core and a glass fibre reinforced outer shell were rapid prototyped and instrumented with strain gauges. Brånemark implants RP platforms in conjunction with titanium Procera one-piece or two-piece bridges were used to simulate oral rehabilitations. A lateral load through the gonion regions was used to test the biomechanical effects of the rehabilitations. In addition, strains due to misfit of the one-piece titanium bridge were compared to those produced by one-piece cast gold bridges. Milled titanium bridges had a better fit than cast gold bridges. The stress distribution in mandibular bone rehabilitated with a one-piece bridge was more perturbed than that observed with a two-piece bridge. In particular the former induced a stress concentration and stress shielding in the molar and symphysis regions, while for the latter design these stresses were strongly reduced. In conclusion, prosthetic frameworks changed the biomechanics of the mandible as a result of both their design and manufacturing technology.

The study evaluated a null-hypothesis of no differences of fit between stock abutments and CAD/CAM titanium, gold sputtered and zirconia abutments when examined for radiographic adaptation and Scanning Electron Microcopy (SEM) at their inner aspect. The agreement between microscopic and radiographic fit was also assessed.Implants (Osseospeed, Astra Tech, Mölndal, Sweden) were connected to titanium abutments (Ti-design, Astra Tech, Mölndal, Sweden) (control group n=12), to stock zirconia abutments (Zir-design, Astra Tech) (group 1 n=12) and to third party zirconia abutments (Aadva Zr abutment, GC, Tokyo, Japan) as observed under SEM (JEOL JSM-6060LV, Tokyo, Japan). Two independent operators blindly evaluated the images, according to a three-score scale: perfect adaptation, no complete adaptation, and clear evidence of no adaptation. A Kruskal-Wallis test was applied to assess significant differences in adaptation scores between the groups.All specimens showed precise SEM adaptation at all tested interfaces and no radiographically apparent gaps. No significant differences were found and therefore the null-hypothesis tested was accepted. Radiographic and SEM scores were in agreement.CAD/CAM titanium, gold sputtered and zirconia abutments and third-part CAD/CAM zirconia abutments show an adaptation to Astra Tech implants that is comparable to that of stock titanium and zirconia abutments. Clinicians might be able to verify such adaptation with an x-ray. In-vivo studies would be needed to evaluate the clinical outcome of CAD/CAM abutments.

To evaluate, on the base of cone beam computed tomography (CBCT) fractal dimension, bone quality changes surrounding the apical portion of immediate implants placed under higher insertion torque utilizing an undersized drilling technique.Three patients were enrolled in this study. Single implants were placed into fresh extraction sockets in the anterior maxilla and provisionalized immediately. Adequate stability was ensured on all the implants by a 28.5% undersizing of the apical portion of the osteotomy. Bone quality at the most apical 1.15 mm peri-implant bone portion were measured by CBCT at placement and after 6 months. This analysis was carried out by evaluating the box counting fractal dimension of 15 consecutive CBCT slices related to the most apical part of each implant.All the three implants were successful after an 18-month follow-up period. The mean fractal dimension at the implant apex exhibited a 3% increase 6 months following placement.Within the limitations of an explorative study, an undersized drilling resulting in high insertion torque would seem to induce no adverse changes in radiographic bone quality after 6 months of follow-up. The most favorable entity of drilling undersizing and its effect on peri-implant bone remodeling, should be evaluated on a larger patient population.

Introduction Several miniscrews are available for skeletal anchorage. They have different geometries with self-drilling or self-tapping features. The aim of this study was to evaluate the soft bone primary stability of 3 different orthodontic screws by using the resonance frequency analysis. Methods Aarhus mini-implant (Aarhus Mini-implant, Charlottenlund, Denmark) (A), Mini Spider Screws (HDC, Sarcedo, Italy) (S), and Micerium Anchorage System (Micerium, Avegno, Italy) (MAS) were investigated. To be compatible with the device used for resonance frequency analysis, the screws were modified (an abutment [Astra Tech, Molndal, Sweden] was soldered on top). Four screws per system were tested. Each screw was placed in 5 excised rabbit femoral condyles, providing experimental models of soft bone. Placement was drill-free for the A screw, whereas the MAS and S screws required a pilot hole through the cortical layer. After each placement procedure, resonance frequency was assessed as a parameter of primary stability. Differences among the systems were analyzed by using analysis of variance for repeated measures, with the level of significance at P Results The recorded resonance frequencies (in Hz) were (mean ± SD): MAS, 6236.1 ± 192.1; S, 6270.1 ± 99.7; and A, 6193.1 ± 142.4. Differences among the groups were not statistically significant ( P > 0.05). Conclusions The resonance frequency analysis is applicable to comparatively assess the primary stability of orthodontic miniscrews. The 3 systems had similar outcomes in an experimental model of soft bone.

Owing to the increasing use of dental implants to restore edentulous conditions, clinicians often face situations where available bone volumes are reduced and need to be augmented before implant placement. This is common in the posterior maxilla, where the presence of the maxillary sinus combined with severe atrophy of the bone crest, owing to long-standing edentulism or pathological conditions, might preclude implant placement. Techniques to augment the sinus floor in combination with several grafting materials are commonly used to restore adequate volumes for implantation. Recent studies have described bone reformation and integration of oxidized implants by simple elevation of the sinus membrane without any grafting material. The aim of this case report is to document the application of the sinus membrane elevation technique in combination with the placement of 3 blasted microthreaded implants in a patient who was clinically and radiographically followed up for 3 years. During the follow-up period, the blasted implants were all stable and intraoral radiographs showed that the bone reformed in contact with the implants and remained stable.

Background: Resonance frequency (RF) analysis is frequently used to monitor implant stability in patients. The influence of transducer orientation on RF of implants placed in jawbone has not been evaluated. Purpose: The aim of this study was to evaluate to what extent transducer orientation influences RF. The second aim was to evaluate if measurements taken with any particular orientation would best relate to marginal bone levels. Materials and Methods: Nine patients edentulous in the upper jaw received 55 implants 3 years before this study. They underwent clinical and radiographic evaluation. Using OsstellTM (Integration Diagnostics AB, Goteborg, Sweden), four RF measurements were made for each implant. Measurements were obtained with the transducer cantilever placed buccally (B), distally (D), palatally (P), and mesially (M). Results: All implants were clinically stable. Significant differences resulted between the measurements perpendicular to the bony crest (B, P) and the parallel ones (M, D). A tendency of negative correlation was found between marginal bone levels and implant stability quotient (ISQ) measurements; however, this correlation was not statistically significant. Conclusions: In conclusion, when measuring the RF of dental implants using the Osstell, it has to be taken into account that the transducer orientation influences the measurement. It seems therefore advisable to standardize the orientation. Moreover, although there was a tendency, any statistical significant correlation between ISQ values and marginal bone levels could not be established.

Objectives: The aim of this study is to investigate whether the damping of osseointegrated implants, as measured quantitatively with the Osstell™ equipment, is related to the fractal dimension of peri-implant bone. Material and methods: Fifty-five maxillary implants in function for 3 years before the present study were investigated. Two Osstell™ measurements were obtained for each implant with the transducer oriented first palatally and then distally. Using the half-power bandwidth method, the damping was calculated from the frequency/amplitude plot obtained from the Osstell™. Damping data were then related to the fractal dimension of peri-implant bone. Fractal dimensions were calculated using a box-counting algorithm on digitally processed intra-oral radiographs of the implants. A Spearman's test was used to verify the correlation between damping and fractal dimension values. Results: All the implants were clinically stable and free from symptoms. The mean ISQ was 63 for the palatal orientation and 71 for the distal orientation. The mean fractal dimension was 1.47; the mean damping value for palatal orientation was 12.3%, while that for the distal orientation was 8.2%. No significant correlation was found. Conclusions: Damping values, measured at peri-implant bone, were found not to be related to a radiographic parameter of trabecular bone pattern like the fractal dimension. The clinical implication would be that Osstell™ graphs displaying distinct or more rounded peaks might both indicate a stable implant as long as the associated implant stability quotients are in the range of satisfactory values proposed in the literature.

The giant cell tumor of the jaws is a rare benign lesion, it has a slow and progressive evolution and it is locally aggressive. Its etiopathogenesis is unknown, it is most common in the mandible and it is often asymptomatic but pain arises from palpation of the area. Diagnosis is made by radiological and histological examination and surgical treatment is necessary. The clinical case of a 28-year-old man affected by a giant cell tumor of the mandible with an aggressive clinical and radiographical behaviour is reported. The patient showed a jaw swelling covered by hyperemic fibro-mucous tissue from tooth 4.6 to 3.4, absence of cortical bone and mobility of teeth. He also reported lip anesthesia. The giant cell tumor diagnosis was made with orthopantomography (OPT), computed tomography (CT) and needle biopsy. The lesion was surgically removed and histological examination confirmed the diagnosis. In spite of the wide loss of bony substance after surgery, the patient was provided with an implant supported fixed prosthesis without previous bone graft. In this case short implants allowed the prosthetic rehabilitation of a mandible with severe ''resorption'' due to surgical removal of a tumor. Implants were placed in the residual bone volume and successfully used to support a fixed prosthesis. The final result is optimal as is the quality of life of the young patient.

Insertion torque and resonance frequency analysis are currently used to assess the initial biomechanical competence of an implant. It would be advantageous to have this information during treatment planning. Therefore, the aim of this study was to assess the correlation between a descriptor of bone architecture, namely the fractal analysis of plain radiographs, and implant insertion torque and resonance frequency.Sixteen femoral condyles from adult rabbits were subjected to conventional radiography and then received an implant each. The final insertion torque and resonance frequency were recorded for each implant. The fractal dimension of the bone area corresponding to the osteotomy was calculated using a box-counting algorithm. The Spearman test was used to evaluate the correlation between the variables examined.A linear correlation was observed between fractal dimensions and insertion torque values (rs = 0.704; P = .007). No correlation resulted between fractal dimension and resonance frequency. In addition, a receiver operating characteristic analysis defined a fractal dimension breakpoint of 1.83 to detect soft bone quality, as defined by insertion torque values, with a sensitivity of 80%.Given its correlation with insertion torque, the box-counting fractal dimension could be useful to evaluate bone quality at implant sites preoperatively and noninvasively. Further studies are needed to confirm the same accuracy for human bone.