The single midline implant in the edentulous mandible: a systematic review

Objectives

The concept of a single midline implant retaining a complete mandibular denture is controversially discussed among experts. Studies are rare in the literature, and commonly accepted recommendations for this treatment options are not available. This systematic literature review was performed to give an overview over the current literature on the single midline implant therapy for the edentulous mandible and to reveal whether this treatment option might be an alternative to commonly accepted treatment modalities with more implants.

Methods

A review of the literature published until 24th of May 2013 was conducted to identify in vivo studies on the single midline implant concept with a mean follow-up time of at least 3 months.

Results

From the electronic search, 11 studies were finally included. After an observation period of 3–60 months, the implant survival rate ranged from 62.5 to 100 %. The most frequent prosthetic maintenance intervention was “activation of the matrix” followed by “repair of fractured denture base.”

Conclusions

The concept of one single midline implant to retain a mandibular complete denture can be an alternative, especially for elderly patients. Immediate loading of the implants should be avoided, and the way of integrating the matrix into the denture base should be carefully considered.     

Electrical mallet provides essential advantages in split-crest and immediate implant placement

Purpose

The aim of this prospective study was to compare the use of a hand mallet versus an electrical mallet in osteotome-assisted surgery for split-crest procedures.

Methods

Partially edentulous patients, with an alveolar ridge width inferior to the optimally desirable implant diameter, were selected for this study. Forty-six split-crest procedures were performed in 46 patients. They were randomly divided in two groups: in the control group, 23 patients, the split crest was performed with osteotomes using a handheld mallet, while in the test group, 23 patients, the split crest was prepared with osteotomes using an electrical mallet. Alveolar ridge width and incision dimensions were measured with a periodontal probe, before and after the split-crest procedure. One hundred eighty-one implants were immediately placed. Follow-up examinations were performed at baseline and 6, 12, and 24 months.

Results

The survival rate, at 2-year follow-up, was 98.31 %. Indeed, two implants placed in the maxilla failed to integrate at second-stage surgery. The initial width of the alveolar ridge varied from 2 to 3.5 mm; the average was 2.8?±?0.7 mm. The final ridge width varied from 5 to 8 mm; the average was 7.2?±?1.7 mm. The split length varied from 7 to 28 mm; the average was 17.5?±?7.7 mm. No statistically significant differences (P?>?0.05) were found between test and control group in split length and alveolar width values before and after the split-crest procedure.

Conclusions

The use of a magnetic mallet provided some essential clinical advantages during crest splitting and immediate implant placement in comparison with a hand mallet.     

The influence of bone substitute materials on the bone volume after maxillary sinus augmentation: a microcomputerized tomography study

Objectives

This study aims to evaluate the effect of adding bone substitute materials (BSM) to particulated autogenous bone (PAB) on the volume fraction (Vf) of newly formed bone after maxillary sinus augmentation.

Materials and methods

Thirty healthy patients undergoing maxillary sinus augmentation were included. PAB (N?=?10), mixtures of PAB and beta-tricalciumphosphate (PAB/β-TCP) (N?=?10), as well as PAB and β-TCP and hydroxyapatite (PAB/HA/β-TCP) (N?=?10) were randomly used for sinus augmentation. A sample of the graft material was maintained from each patient at time of maxillary sinus augmentation, and Vfs of the PAB and/or BSM in the samples were determined by means of microcomputerized tomography (μ-CT). Five months later, samples of the grafted areas were harvested during implantation using a trephine bur. μ-CT analysis of these samples was performed, and the Vf of bone and BSM were compared with the data obtained 5 months earlier from the original material.

Results

The mean Vf of the bone showed a statistically significant increase (p?<?0.05) in all groups after a healing period of 5 months without statistically significant difference between the groups.

Conclusions

With regard to the increase of bone volume, it is not relevant if PAB is used alone or combined with β-TCP or HA/β-TCP.

Clinical relevance

The amount of PAB and associated donor site morbidity may be reduced by adding BSM for maxillary sinus augmentation.     

Performance of coralline hydroxyapatite in sinus floor augmentation: a retrospective study

Objective

The purpose of this study is to retrospectively explore the utilization of coralline hydroxyapatite in maxillary sinus augmentation.

Method

One hundred and eighteen cases of sinus lift with coralline hydroxyapatite (CHA) were included in this study. In detail, simultaneous implantation was conducted in 78 patients (174 implants) and delayed implantation was done in 40 cases (82 implants) around 6 months after bone transplantation. The clinical features and X-ray radiographs after operation were analyzed to evaluate osseointegration procedures according to a planned medical follow-up. In the delayed group, around 6 months, a bone biopsy was taken just during implant placement in order to evaluate the new formed bone from a histological and histomorphometrical point of view. A further 6 months later, abutment connection was performed, and the patients received prosthetic restoration of the missing teeth.

Result

Clinically, the incisions healed well. No abnormal reactions were found during follow-up period. All the 174 simultaneous implants were successful after 1–5 years of medical review; Out of 82 delayed implants, 3 were found to be loose. Histologically, all the specimens showed signs of active remodeling, and all the tissues had a large amount of osteocyte at sixth month after sinus augmentation. New bone formed dramatically. Radiologically, the density of CHA gradually reduced since the beginning of the third month, and CHA may be completely resolved at about fifth year.

Conclusion

CHA is proven an ideal bone graft material for its reliable clinical results and favorable histocompatibility in the treatment of sinus atrophy or other kinds of insufficient bone volume in this region. Moreover, CHA’s signal application can achieve desired clinical effect.

Clinical relevance

This study shows the clinic application of CHA in maxillary sinus augmentation. Compared with popular mixture of autogenous bone and grafting materials, our results show CHA’s signal application can achieve ideal osseointegration interface and satisfying clinic effect.     

Complications related to bone augmentation procedures of localized defects in the alveolar ridge. A retrospective clinical study

Purpose

This retrospective clinical study aims to evaluate complications after augmentation of localized bone defects of the alveolar ridge.

Methods

From standardized registrations, the following complications related to bone augmentation procedures were recorded: soft tissue dehiscence, infection, sensory disturbance, additional augmentation procedures needed, and early implant failure.

Results

A total of 223 patients (132 women, 91 men; mean age 23.5 years; range 17–65 years) with 331 bone defects had bone augmentation performed into which 350 implants were placed. Soft tissue dehiscence occurred in 1.7 % after GBR procedures, 25.9 % after staged horizontal ridge augmentation, and 18.2 % after staged vertical ridge augmentation. Infections were diagnosed in 2 % after GBR procedures, 12.5 % after sinus floor elevation (SFE) (transcrestal technique), 5 % after staged SFE, 11 % after staged horizontal ridge augmentation, and 9 % after staged vertical ridge augmentation. Additional augmentation procedures were needed in 2 % after GBR procedures, 37 % after staged horizontal ridge augmentation, and 9 % after staged vertical ridge augmentation. A total of six early implant failures occurred (1.7 %), four after GBR procedures (1.6 %), and two (12 %) after staged vertical ridge augmentation.

Conclusions

Predictable methods exist to augment localized defects in the alveolar ridge, as documented by low complication rates and high early implant survival rates.

     

Biomechanical effects of the implant material and implant–abutment interface in immediately loaded small-diameter implants

Objective

Small-diameter implants have been available since the 1990s, but few studies have analyzed their mechanical properties. This study evaluated the effects of the implant material and the implant–abutment connection designs on the primary stability and the marginal bone strain of small-diameter implant subject to immediate loading.

Materials and methods

Insertion torque value (ITV), implant stability quotient (ISQ), and Periotest value (PTV) of three implant systems with four parameters (titanium, titanium alloy, internal and external hexagon connections) were measured after placing implants into artificial type 2 jaw-bone models. Specimens were tested under both vertical and oblique static loads at 190 N. Peak values of the principal bone strain were recorded and analyzed statistically by the Kruskal–Wallis test and multiple-comparisons Bonferroni test.

Results

PTV and ISQ were higher for the NIOSM311 (internal-hex and Ti alloy) and FOSM311 (external-hex and pure Ti) implants, respectively, than for the NOSM311 (external-hex and Ti alloy) implant. Under vertical loading the peak value of peri-implant bone strains did not differ significantly among these three implant systems. However, the peak bone strains were at least 32 % lower for the NIOSM311 and FOSM311 implants than for the NOSM311 implant under lateral loading.

Conclusions

The implant material and the implant–abutment connection design significantly influence the peri-implant bone strain of immediately loaded small-diameter implants, but barely affect their primary stability.

Clinical Relevance

A commercially pure titanium implant with an internal connection has the potential to reduce the risk of implant failure of small-diameter implant related to biomechanical complications.     

Assessment of implant stability following sinus lift procedures with different grafting materials

Objective

The objective of this research was to evaluate implant stability following sinus lift with two grafting materials, and to compare it with the results obtained for the implants placed in a pristine posterior maxilla.

Materials and methods

The study included 44 healthy patients with an existing indication for sinus lift procedure (test group). 46 implants were placed following sinus lift with a pure-phase beta-tricalcium phosphate, while 39 implants were placed following augmentation with 60% hydroxyapatite with 40% beta-tricalcium phosphate material. The control group consisted of 48 healthy patients who were treated with 85 implants but without bone augmentation in posterior maxilla. Astra Tech OsseoSpeed implants were placed in all subjects. Resonance frequency analysis was used in both groups for determining implant stability 4 months after insertion. A mean implant stability quotient (ISQ) was calculated on the basis of 3 measurements.

Results

No statistical difference was observed in ISQ values of implants placed with and without augmentation procedure (p=0,789). Statistically significant difference was not found when ISQ values of implants placed following particular grafting material were compared with ISQ values of corresponding implants in a pristine bone (p=0.697 and p=0.402).

Conclusions

This study demonstrated that the implant stability is comparable among implants placed in the posterior maxilla regardless of sinus lift and grafting procedure. Implants placed in the grafted posterior maxilla can be predictably loaded as the implants placed in a non-grafted, pristine maxilla.Key words: Dental Implants, Sinus Floor Augmentation, Resonance Frequency Analysis, Beta-tricalcium Phosphate, Hydroxyapatite     

Retrospective Clinical Study of Marginal Bone Level Changes with Two Different Screw-Implant Types: Comparison Between Tissue Level (TE) and Bone Level (BL) Implant

Aim

The objective of this retrospective cohort study was to compare the amount of marginal bone loss (MBL) in a bone-level and a soft-tissue-level implant system, both of which have similar intra-bony shape and surface composition. A subgroup analysis was done to compare the amount of MBL of each implant type in relation to the different vertical placement within the respective groups of implants.

Materials and Methods

Records of all patients who underwent implantation for replacement of teeth using comparable bone level (BL) and soft tissue level implants (TE) from 1st January 2006 to 31st December 2009 were scrutinized. Initial depth of implant placement (IDIP) was measured for all implants. Marginal bone loss was measured in patients whose records were available at time point corresponding to 12, 24 and 36 months post insertion.

Results

Out of a total of 384 implants, 337 implants were included for study. The mean MBL for the BL implants were 0.3, 0.38, 0.48 and for TE implant were 0.6, 0.54 and 0.93 for time periods 12, 24 and 36 months respectively. Although there was no statistically significant difference between the two groups at time periods at 6–12 months, in later time periods, there was a slightly greater amount of MBL around TE implants as compared to BL implants (p < 0.001). When comparing the IDIP and MBL in the same implant type, there was a statistically significant (p < 0.001) positive correlation between the depth of implant placement and the amount of MBL, with deeper placed implants having more bone loss.

Conclusion

Within the limitations of this retrospective cohort study design, one can conclude that BL implants had statistically significant lesser MBL as compared to TE in time periods above 12 months. Although the difference is statistically significant, the difference may not be clinically significant. The IDIP had an influence on the amount of MBL, with deeper placed implants and screw structure of the implant placed below the bone, having more MBL in the period of study.     

Immediate loading of implants in the edentulous mandible: a multicentre study

Purpose

The aim of this prospective study was to investigate the two-year outcomes following immediate loading of mono-cortically engaged implants.

Materials and methods

Thirty healthy mandible edentulous patients with an average age of 67.3 years and presenting with sufficient bony ridge at the mandible symphysis were included in the study. Four Astra Tech, Ti-Oblast^® implants were installed between the mental foramina using the mono-cortical anchorage technique. The primary stability of the implants was assessed by resonance frequency analysis (RFA). After uni-abutments were placed, a temporary bridge was constructed and fixed the same day. The definitive bridges were installed 6 weeks after implant surgery. Five of 120 placed implants were lost in four patients during the first 6 weeks and these patients were excluded from the follow-up. The changes in marginal bone level (n = 20) were evaluated in Brazilian and Swedish groups at baseline, 6 weeks, 6 months, 12 months and 24 months. The RFA (n = 30) was evaluated at baseline, 6 weeks, 6 months, 12 months and 24 months postoperatively.

Results

Compared with baseline measurements, the postoperative values for marginal bone level (6 weeks, 6 months, 12 months and 24 months) were significantly reduced (p < 0.05), while no differences were observed in the RFA analysis (12 months and 24 months).

Conclusions

The immediate loading of mono-cortically engaged implants in the edentulous mandible is safe and predictable and implant stability remains excellent after 2-year follow-up.

     

Risk factors associated with post-loading implant loss of removable and fixed implant-supported prostheses in edentulous jaws

Purpose

This study analyzed risk factors for post-loading implant loss in cases of implant-supported prostheses applied to edentulous jaws of Japanese patients.

Cervical metastases of squamous cell carcinoma of the maxilla: a retrospective study of 25 years

Objectives

Squamous cell carcinomas (SCCs) of the maxilla are relatively rare; therefore, only little data is available regarding the frequency of cervical metastasis (CM) and therapy strategies. Most authors only undertake clinical observation of the lymph nodes. The aim of this retrospective study was to evaluate the manner of metastasis in SCC of the maxilla.

Materials and methods

All patient records from 1987 to 2011 were scanned for SCC of the maxilla. Patients with SCC limited to the maxilla were comprised. The cases were analyzed regarding tumor node metastasis staging system and any special occurrences in the follow-up time such as tumor recurrence, metastasis, and exitus letalis. Classification and staging were performed according to the 2003 UICC system.

Results

One hundred thirty-eight patients were comprised of 36 % females and 64 % males (average age, 66 years; women, 71 years; men, 63 years). The average follow-up time was 43 months (range, 0–195). Fifty-eight percent smoked or declared regular consumption of alcohol. About 50 % of the patients had an advanced tumor stage (III–IV). At the time of the primary diagnosis, 38 % of the patients had CM. There is an increased risk for CM occurrence with increasing tumor size and grading and a tumor localized in the postcanine region. Contralateral CM arises frequently in T4 tumors and tumors localized in the postcanine region.

Conclusion

The data exhibit aggressive regional metastatic behavior of SCC of the maxilla.

Clinical relevance

Therefore, surgical treatment of the draining lymphatic system as a primary management strategy is recommended for patients with SCC of the maxilla.     

Accuracy of peri-implant bone thickness and validity of assessing bone augmentation material using cone beam computed tomography

Objectives

The aim of this study was to evaluate the accuracy of measuring bone thickness surrounding dental implants and the reliability of assessing existence and completion of osseous integration of augmentation material using a cone beam computed tomography (CBCT) system.

Materials and methods

In jaws of foxhounds, artificial defects were regenerated by guided bone regeneration and then dental implants were placed. After putting down the dogs, the jaws were separated from the bodies and exposed in a CBCT system. The bone thickness was measured on both buccal and oral sides of the implants at different levels. Every examiner evaluated existence and integration of bone augmentation materials (BAM) and the completeness of marginal implant covering. The same measurements and evaluations were performed at digital images of the corresponding histological sections.

Results

The mean and the standard deviation of the differences between radiological and histological measurements of peri-implant bone thickness were ?0.22 mm and 0.77 mm, respectively. Sensitivity and specificity were 0.77 and 0.60 for existence of BAM, 0.59 and 0.74 for completed integration, and 0.39 and 0.71 for full covering of the implant surface.

Conclusions

The present study indicates that the PaX Duo3D® CBCT system allows measurements of peri-implant bone thickness at an accuracy of half a millimeter, and—within limits—assessing the existence and integration of BAM. It is not possible to evaluate whether the implant is covered completely by hard tissue.

Clinical relevance

Peri-implant bone thickness is a key factor for obtaining initial implant stability. The accuracy of its measurement has clinical impact. Radiological assessment of existence and integration of BAM would be of great benefit to the evaluation of augmentation procedures.     

Kombination der Sinusliftoperation mit der lateralen Kieferkammaugmentation

Purpose

This paper describes a surgical and prosthetic procedure for treating the extremely atrophic maxilla. It explains a two-staged surgical technique, donor and recipient site morbidity, implant survival, and the implant-retained prosthetic rehabilitation of the patients.

Patients and methods

A total of 57 consecutive patients were treated with a sinus lifting procedure and a simultaneous lateral augmentation using autogenous corticocancellous block and particulate bone grafts from the iliac crest. After a 6-month bone healing period, a total of 284 endosteal Titanium screw implants were inserted. Following a 3-month osseointegration period, the implants were exposed and loaded with either fixed or removable prostheses.

Results

In three cases a partial bone graft loss was observed; however, enosseous implantation was possible as planned. During the observation period none of the 284 implants was lost; 3 implants exhibited treatable peri-implant infection. Complications at the donor and recipient sites were minimal and did not negatively influence the overall clinical result of the treatment.

Conclusion

The combination of sinus lift procedure and lateral augmentation for the treatment of the extremely atrophied maxilla proved to be a safe method that produces good and reliable clinical results.     

Computer-assisted flapless implant placement reduces the incidence of surgery-related bacteremia

Objective

Bacteremia—the access of bacterium to the bloodstream—may yield life-threatening complications. The aim of this study was to compare the incidence, duration, and type of bacterium leading to bacteremia with relation to conventional and computer-assisted flapless implant surgery.

Material and methods

A total of 377 implants were placed in 68 edentulous jaws using the conventional (conventional group) or a computer-assisted stereolithographic (SLA) template-guided surgery technique (flapless group). Bacteremia was monitored from pre- and postoperative blood samples.

Results

The duration of the surgical intervention was significantly shorter in the flapless group (p?=?0.3510). Baseline samples were sterile. Following the 15th minute after the placement of the last implant, bacteria were present in 62 and 12 % of the patients in the conventional and flapless groups, respectively (p?<?0.0001; relative risk: 3.05). The differences in the incidence of the bacteremia detected at the baseline and 15 min after the last implant placement were statistically significant in the conventional group (p?=?0.0001). However, no such statistical significance was present in the flapless group. Staphylocccus epidermidis, Bifidobacterium spp., Streptococcus viridans, Corynebacterium spp., and Streptococcus sanguinis were the isolated bacterium.

Conclusions

Irrespective of the utilized technique, bacteremia may occur upon the placement of four to eight implants to an edentulous jaw. The probability of bacteremia for the patients operated with the conventional technique is, however, 3.05 greater than those operated with the flapless technique.

Clinical relevance

Flapless implant placement reduces the incidence of surgery-related bacteremia and, therefore, may be beneficial to patients at risk.     

Effect of decreased implant healing time on bone (re)modeling adjacent to plateaued implants under functional loading in a dog model

Objectives

The purpose of this study was to evaluate the effect of early functional loading to plateaued implants on bone formation and implant stability in a dog model.

Materials and methods

Early loading (EL), nonloading control, and delayed loading (DL) groups were compared using six beagle dogs under functional loading. The Periotest® values were measured dynamically for 6 weeks. Peri-implant bone architecture was evaluated qualitatively by microcomputed tomography (μCT) and analyzed quantitatively by mineral apposition rates (MAR), bone-to-implant contact (BIC), and bone volumes (BV/TV) after the euthanasia at 3 and 6 weeks after loading.

Results

The EL implants showed poor stability at 1 week, but greater stability at 2 and 4 weeks after loading compared to DL implants. There was no significant difference between MAR of EL and unloaded implants at both time intervals. The EL implants displayed a significantly higher MAR when compared to DL implants at 3–5 weeks. A significantly higher BIC for the DL group was observed when compared to the EL group at 3 weeks following loading, however at 6 weeks; no significant difference between these groups was observed. The EL group gained a higher BIC than the no-treatment control group at 6 weeks.

Conclusions

For plateaued implant, the decreased healing time (1 week) displays a positive effect on peri-implant bone (re)modeling under functional loading during the early phase.

Clinical relevance

The early application of functional loading on plateaued implants can be used clinically to shorten the course of treatment and improve esthetics.     

Clinical study evaluating the discrepancy of two different impression techniques of four implants in an edentulous jaw

Objectives

Precise implant-supported prosthodontics requires accurate impressions. Many in vitro studies comparing different implant impression techniques were performed. The purpose of this in vivo study was to compare the discrepancy of two different impression techniques of implants clinically.

Material and methods

Four implants were inserted nearly bilateral in ten edentulous jaws. From each jaw, two different impressions (A, transfer; B, splinted pick-up) were taken. Respectively two stone casts of each jaw were produced and scan bodies were mounted on the lab analogues to digitize the casts. One scan body of the digitized casts was each superimposed and the deviations of the remaining three scan bodies were measured three dimensionally. The fit of the suprareconstructions was evaluated clinically on both casts and in the mouth.

Results

The mean discrepancy of scan body 2 was 192 μm (±96), 282 μm (±97) for scan body 3, and 366 μm (±114) for scan body 4. The discrepancies between two scan bodies were statistically significant (p?≤?0.010; ANOVA test). Comparing the data with the span between the scan bodies, a linear regression line could be drawn to show the dependency between the misfit and the length of the span. Clinically, the fit on the cast produced by the splinted pick-up technique was favorable.

Conclusions

The discrepancy between the splinted pick-up impression technique and the transfer technique were in a range with clinical influence.

Clinical relevance

For better accuracy of implant-supported prosthodontics, the splinted pick-up technique should be used for impressions of four implants evenly spread in edentulous jaws.     

Klinische und radiologische Ergebnisse nach Augmentationen – eine prospektive Evaluation

The clinical follow up of atrophic jaws treated with augmentation procedures and dental implants is demonstrated and evaluated over a period of five years. In total 50 patients (24 male and 26 female) from the department of maxillofacial surgery of the Friedrich Alexander University Erlangen–Nuernberg who received an augmentation procedure were prospectively evaluated. The mean age was 59.1 years on the female and 56.9 years on the male patients. All patients received prior to implant placement an augmentation with autogenous bone or a bone substitute and were reconstructed using a fixed or removable implant borne rehabilitation. Overall 293 implants from five different systems were used, 10 implants on eight patients were lost in the observation period. Three implants were lost during the healing period and seven after prosthetic rehabilitation. This leads to a cumulative survival rate of 96.6%. The success rate, according to the criterions defined by Karoussis et al. [25] was 94.04%. After twelve months in the area of augmentation an overall resorption rate of 26.4 % was found, at five years the rate mounted to 31.67%. Comparing the resorption rates in maxilla and mandible the vertical loss was 35.88%, rsp. 26,05%. Comaring the posterior and anterior augmentation areas the vertical loss was significantly (p: 0.048%) higher in the posterior with 38.72% compared to 28.26% in the anterior region. Measurement of the SFFR (sulcus fluid flow rate) demonstrated a significant (P. 0.03) correlation with bone resorption, meaning that higher SFF rates showed higher rates of vertical resorption. Additionally a high SFF rate correlated with higher pocket depths and reduced keratinized periimplant gingival rates.     

Staged Ridge Split Procedure in the Management of Horizontal Ridge Deficiency Utilizing Piezosurgery

Aim and Objectives

Edentulism is an incapacitating and irretrievable condition which can lead unswervingly to functional limitation, physical, psychological and social handicap. Maintenance of bone after tooth loss to improve retention, function, and performance of the restoration is a challenging task. The existence of a thin edentulous ridge signifies a clinical situation that is more complex for the placement of endosseous implants. Dental rehabilitation of the edentulous ridges with oral implants has become a routine treatment modality in the last few decades with consistent long term results.

Methods

A staged ridge spilt procedure was performed in the maxillary posterior edentulous region employing piezosurgery for the augmentation of horizontal ridge deficiency which was followed by the successful placement of implant supported prosthesis.

Results

At the 20 months follow-up, stable results were appreciated with minimal bone loss around the implants.

Conclusion

This proficient technique precludes the need for a second surgical site for the procurement of graft which in turn decreases patient discomfort. Hence this procedure can be used as an alternative to other strenuous procedures.

     

Dense cancellous bone as evidenced by a high HU value is predictive of late implant failure: a preliminary study

Objectives

The mechanism of late implant failure is unclear. This study examined the association between sclerosing cancellous bone images and the risk of late implant failures using multi-detector row computed tomography (CT) imaging data.

Methods

We performed a case–control study. The study group consisted of consecutive patients with implant failures treated at Kyushu Dental University between 2001 and 2016. CT data for late failure of 36 implants in 16 patients were available. The study cohort consisted of 16 patients with 36 late failed implants and 28 patients with 113 successful implants.

Results

The mean survival rate was 6.9 months for early implant failure, 76.6 months for late failure with marginal bone resorption, inflammation symptoms, and so-called peri-implantitis, and 95.0 months for late failure caused by implant fracture. The mean HU value for cases in the control group was 507 compared with 1231 for cases with late failure implants. Logistic regression was used for analysis. There were signs of high radiodensity of peri-implant cancellous bone when comparing adjusted radiodensity per 100 HU using CT data (OR 2.35; 95% CI 1.73–3.20; p < 0.001).

Conclusions

Within the limits of our study, the presence of high radiodensity and cancellous bone consolidation on imaging may be related to risk factors for late implant failure. Therefore, CT images of the host cancellous bone status for observation of visible sclerosis could be a useful diagnostic indicator for late implant failure.

     

Biomimetic treatment on dental implants for short-term bone regeneration

Objectives

The main purpose of this work was to assess the short-term bone regenerative potential of new osteoconductive implants. The novelty of the study lies in the analysis of the effectiveness of a novel two-step treatment which combines shot-blasting with a thermo-chemical treatment, at very short times after implant placement in a minipig model.

Materials and methods

Three hundred twenty implants with four different surface treatments, namely bioactivated surfaces, micro-rough grit-blasted, micro-rough acid-etched and smooth as-machined titanium implants were placed into the bone of 20 minipigs. The percent of bone-to-implant contact was determined 3 days, 1, 2, 3 and 10 weeks after implant placement by histomorphometric analysis. Surface composition, topography and wettability of the implant specimens were analysed.

Results

The combination of shot-blasting and thermo-chemical treatment accelerated bone regeneration at early stages in comparison with all other treatments between day 3 and week 3 (p?<?0.05). The value of osseointegration attained at week 2 was maintained until the end of the experiment without any significant changes (percent direct contact?≈?85 %). This was mostly attributed to the ability of these implants to form in vivo a layer of apatitic mineral that coated the implant and could rapidly stimulate bone nucleation and growth from the implant surface.

Conclusions

The surface quality resulting from this treatment on cpTi provided dental implants with a unique ability of rapid bone regeneration and osseointegration.

Clinical relevance

This treatment represents a step forward in the direction of reducing the time prior to implant loading.