Peri-implant Bone Defects Research Articles

Evaluation of hard tissue 3-dimensional stability around single implants placed with guided bone regeneration in the anterior maxilla: A 3-year retrospective study

Statement of problemGuided bone regeneration (GBR) is widely used to reconstruct peri-implant bone defects in the esthetic zone. However, the dimensional stability of this bone-biomaterial composite is not fully understood. PurposeThe primary aim was to evaluate the hard tissue 3-dimensional (3D) stability around single implants placed with simultaneous GBR by using deproteinized bovine bone mineral (DBBM) in the anterior maxilla and explore possible influencing factors. Material and methodsThe records of patients who had received implants in the anterior maxilla from January 2015 to March 2016 were reviewed retrospectively. The change in volume and thickness of the facial hard tissue were analyzed. To explore possible influencing factors, the thickness and surface area of facial graft were measured, and the time point at which implants were placed and the healing protocol were recorded. Secondary outcome measures were peri-implant marginal bone loss, bleeding on probing (BOP), and pink esthetic score (PES). Statistical analysis was conducted by using the Student t test, Mann-Whitney U test, Kruskal-Wallis test, or generalized estimating equation analysis (α=.05). ResultsFifty-five participants were included in this study, and no implants had been lost after 3 years. BOP was present in 10 (18.2%) participants. The mean ±standard deviation PES of all implants for this study was 11.0 ±2.1. The mean ±standard deviation percentage of residual hard tissue volume was 36.9 ±23.5%, with a significant difference found between time points before 9 months (P<.05). Type 3 implant placement (OR=1.449, P=.031) was found to have a higher percentage of residual hard tissue volume. A greater reduction of the facial hard tissue thickness was observed in participants with thicker postoperative facial grafting (OR=1.463, P=.001). No statistically significant difference was found between the facial, palatal, mesial, and distal peri-implant sites in terms of marginal bone loss (P>.05). ConclusionsAlthough single-tooth implant placement combined with GBR using DBBM in the anterior maxilla offered satisfactory esthetic and functional outcomes after a 3-year follow-up, significant hard tissue volume and thickness reduction in grafted sites was detected, especially during the initial 9-month postoperative period. This phenomenon may be correlated with the timing of implant placement and the thickness of the facial graft.

In Vitro Efficacy of Three Different Nonsurgical Implant Surface Decontamination Methods in Three Different Defect Configurations.

Assessment of in vitro efficacy of three different nonsurgical implant surface decontamination methods in three peri-implant bone defect simulation models. A total of 180 implants were allocated to differently angulated (30, 60, and 90 degrees) peri-implant bone defect resin models, each covered by a mucosa mask. All implants were stained with indelible red color and assigned to one of the three defect models. In each simulated bone defect group, 20 implants were decontaminated for 2 minutes with a curette (CUR), sonic scaler (SOSC), or air-powder abrasion device (APA) with glycine powder. Photos were taken from both sides of each implant to measure the percentage of uncleaned implant surface area. Scanning electron microscopy (SEM) was used to assess the implant surface for morphologic damage. Among the three defect angulations, a significantly different cleaning efficacy (P < .001) for each treatment method was found (30 degrees: CUR [67.33%], SOSC [62.70%], APA [39.33%]; 60 degrees: CUR [61.59%], SOSC [54.31%], APA [23.91%]; 90 degrees: CUR [66.82%], SOSC [55.77%], APA [28.03%]). SEM did not show any considerable surface damage after APA treatment in comparison with after CUR or SOSC. Air-powder abrasion proved to be the most efficient nonsurgical treatment device for each type of defect in this in vitro model with the least noticeable surface change. No decontamination method resulted in complete cleaning of the color remnants on the implant surface.

Diagnostic accuracy of CBCT versus intraoral imaging for assessment of peri\u2010implant bone defects

BackgroundEarly detection of marginal bone loss is vital for treatment planning and prognosis of teeth and implant. This study was conducted to assess diagnostic accuracy of CBCT compared to intra-oral (IO) radiography for detection, classification, and measurement of peri-implant bone defects in an animal model.MethodsFifty-four mandible blocks with implants were harvested from nine male health adult beagle dogs with acquisition of IO, CBCT and micro-CT images from all samples. Peri-implant bone defects from 16 samples were diagnosed using micro-CT and classified into 3 defect categories: dehiscence (n = 5), infrabony defect (n = 3) and crater-like defect (n = 8). Following training and calibration of the observers, they asked to detect location (mesial, distal, buccal, lingual) and shape of the defect (dehiscence, horizontal defect, vertical defect, carter-like defect) utilizing both IO and CBCT images. Both observers assessed defect depth and width on IO, CBCT and micro-CT images at each side of peri-implant bone defect via CT-analyzer software. Data were analyzed using SPSS software and a p value of < 0.05 was considered as statistically significant.ResultsOverall, there was a high diagnostic accuracy for detection of bone defects with CBCT images (sensitivity: 100%/100%), while IO images showed a reduction in accuracy (sensitivity: 69%/63%). Similarly, diagnostic accuracy for defect classification was significantly higher for CBCT, whereas IO images were unable to correctly identify vestibular dehiscence, with incorrect assessment of half of the infrabony defects. For accuracy of measuring defect depth and width, a higher correlation was observed between CBCT and gold standard micro-CT (r = 0.91, 95% CI 0.86–0.94), whereas a lower correlation was seen for IO images (r = 0.82, 95% CI 0.67–0.91).ConclusionsThe diagnostic accuracy and reliability of CBCT was found to be superior to IO imaging for the detection, classification, and measurement of peri-implant bone defects. The application of CBCT adds substantial information related to the peri-implant bone defect diagnosis and decision-making which cannot be achieved with conventional IO imaging.

Diagnostic accuracy of imaging examinations for peri-implant bone defects around titanium and zirconium dioxide implants: A systematic review and meta-analysis.

PurposeThis systematic review and meta-analysis assessed the diagnostic accuracy of imaging examinations for the detection of peri-implant bone defects and compared the diagnostic accuracy between titanium (Ti) and zirconium dioxide (ZrO2) implants.Materials and MethodsSix online databases were searched, and studies were selected based on eligibility criteria. The studies included in the systematic review underwent bias and applicability assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool and a random-effect meta-analysis. Summary receiver operating characteristic (sROC) curves were constructed to compare the effect of methodological differences in relation to the variables of each group.ResultsThe search strategy yielded 719 articles. Titles and abstracts were read and 61 studies were selected for full-text reading. Among them, 24 studies were included in this systematic review. Most included studies had a low risk of bias (QUADAS-2). Cone-beam computed tomography (CBCT) presented sufficient data for quantitative analysis in ZrO2 and Ti implants. The meta-analysis revealed high levels of inconsistency in the latter group. Regarding sROC curves, the area under the curve (AUC) was larger for the overall Ti group (AUC=0.79) than for the overall ZrO2 group (AUC=0.69), but without a statistically significant difference between them. In Ti implants, the AUCs for dehiscence defects (0.73) and fenestration defects (0.87) showed a statistically significant difference.ConclusionThe diagnostic accuracy of CBCT imaging in the assessment of peri-implant bone defects was similar between Ti and ZrO2 implants, and fenestration was more accurately diagnosed than dehiscence in Ti implants.

Influence of preformed bone defects on key pathogens and bone loss during experimental peri-implantitis formation in a canine model.

To determine the impact of experimentally preformed peri-implant crater-shaped bone defects on the evolution of in situ microbiota and development of bone defects compared to those induced over time by ligature placement only. Implants were installed in the mandibles of eight dogs. Standardized bone defects were preformed in four test animals but not in the other four control animals, prior to implant (3.3 mm × 8 mm) installation. After 2 months of healing, peri-implantitis was induced with silk ligatures in both groups for 2 months. Microbial samples were obtained from implants and teeth for analysis at three time points (qPCR), and the average depths of the bone defects were measured. At the baseline, the total marker load of periodontal-pathogenic bacteria (TML) for teeth accounted for 5.2% (0-17.4%). After implant healing, TMLs for implants and teeth were comparable (7.1% [0.3-17.4%]). The TML of both groups was 3.5%, 2 months after ligature placement. Bone defects had a mean depth of 1.84 mm at preformed defects and 1.64 mm at control sites (P > 0.05). Preformed defects in the test group showed comparable results to the control group in terms of TML, the incidence of periodontal-pathogenic bacteria, and bone defect depth.

Evaluation of Effectiveness of Synthetic Bone Graft using with Injectable Platelet-Rich Fibrin on Treatment of Peri-implant Bone Defects: A Retrospective Study

Evaluation of Effectiveness of Synthetic Bone Graft using with Injectable Platelet-Rich Fibrin on Treatment of Peri-implant Bone Defects: A Retrospective Study

Efficacy of Periapical Radiography and Three Cone-Beam Computed Tomography Systems for Detection of Peri-Implant Dehiscence Defects: An in- Vitro Study.

Background: Early detection of peri-implant bone defects is highly important because these defects eventually lead to gingival recession, bone loss and implant failure.Objective: This study aimed to assess and compare the efficacy of periapical radiography and three CBCT systems for the detection of peri-implant dehiscence defects.Material and Methods: In this vitro study, 124 titanium implants were placed in bovine ribs. The bone pieces were then mounted in boxes in the form of mandible and red dental wax was used to simulate the soft tissue. Crestal bone defects with 2, 3, and 4 mm depth were created in the ribs using a round bur. Periapical and CBCT images were then obtained. Images were investigated by two oral and maxillofacial radiologists twice with a two-week interval. The results were analyzed using chi-square, Kappa coefficient, Cochrane’s Q and McNemar tests as well as the receiver operating characteristic (ROC) curve.Results: The two observers showed good agreement in detection of sound and defective samples on periapical radiographs and CBCT scans. The level of agreement was low in detection of two samples with 2 mm defects on CBCT scans taken with Planmeca and NewTom 3G systems at the time of second assessment. NewTom 3G had the highest sensitivity (68.9%, 74.2% and 86.3%, respectively) and specificity (100% for all three) compared to other systems for detection of 2, 3 and 4 mm crestal bone defects. Conclusion: The inter-observer agreement increased with increase in depth of defects. NewTom 3G had the highest accuracy for detection of crestal bone defects.

Intra- and inter-observer agreements in detecting peri-implant bone defects between periapical radiography and cone beam computed tomography: A clinical study

Background/purposeInformation regarding agreements between periapical radiograph (PA) and cone beam computed tomography (CBCT) in detecting peri-implant defect is still scarce. The aim of this clinical study was to compare agreements between PA and CBCT in detecting peri-implant bone defect. Materials and methodsThis retrospective clinical study enrolled 32 patients with both PA and CBCT filmed right after implant placement. Four modalities were used for film reading: PA1 (original), PA2 (enhanced brightness/contrast), CBCT1 (selected axial and mesial-distal direction images) and CBCT2 (all data with software). 2 experienced and 2 inexperienced observers scored all films. Intra- and inter-observer agreements were estimated with Cohen's kappa coefficient. Categorized agreements were compared and differences among four modalities were calculated. ResultsAgreements of PA were better than CBCT when detecting peri-implant bone defects in inter-observer agreements (median kappa 0.471 vs. 0.192; p = 0.016). Moreover, agreements in experienced observers were better than inexperienced observers (median kappa 0.883 vs. 0.567; p < 0.001). There was significant difference among four modalities except for experienced observer 2 (p = 0.218). ConclusionAgreements of PA are better than CBCT when detecting peri-implant bone defects, especially for inter-observer agreements. Experienced observers are more consistent in assessment than inexperienced ones.

Preclinical study of the effects of fluorinated porcine hydroxyapatite in repairing peri-implant bone defects in canine mandible

Objective: To evaluate the effects of fluorinated porcine hydroxyapatite (FPHA) on guided bone regeneration of peri-implant buccal bone defects in canine mandible. Methods: Six male beagle dogs were randomly divided into two groups with different time points (4 weeks and 12 weeks after implants placement), with 3 dogs in each group. Bilateral mandibular second premolars, first molars, and second molars in each dog were extracted. The wounds were allowed to heal for 12 weeks. For each dog, four implant beds were prepared in each side and standardized peri-implant buccal bone defect was created at each implant site. After implants placement, the defect sites were randomly allocated in a split-mouth design to blank control group, deproteinized bovine bone mineral (DBBM), the porcine hydroxyapatite (PHA), FPHA and covered with collagen membranes. The animals were sacrificed 4 or 12 weeks after the surgery. Biopsies of the implant sites were obtained for micro-CT evaluation [bone volume fraction (BV/TV) and bone trabecular separation degree (Tb.Sp)] and histological analysis. Results: Micro-CT results showed that 4 weeks after implants placement, PHA, FPHA and DBBM successfully maintained the contour of alveolar ridge at the buccal aspect of the implants, while the contour of alveolar ridge collapsed in the blank control group. BV/TV in the FPHA group [(24.77±2.20) %] was significantly higher than that in the PHA group [(16.89±1.70)%] and DBBM group [(15.68±3.15)%] (P<0.05). Tb.Sp in the FPHA group (0.70±0.07) was significantly lower than that in the DBBM group (1.03±0.19) (P<0.05). Twelve weeks after implants placement, the alveolar ridge contour of the grafted sites in PHA, FPHA and DBBM group remained stable. The alveolar ridge of the blank control group was still collapsed. There was no significant difference in BV/TV and Tb.Sp between PHA group, FPHA group and DBBM group. The histomorphological analysis showed that 4 weeks after implants placement, in the central area of the defect, the amount and maturity of new bone (NB) around the material particles in FPHA group was higher than that in PHA group and DBBM group. Osseointegration could be observed between the NB and implant surface in all the four groups. Twelve weeks after implants placement, the material particles were surrounded by a large number of mature NB in PHA, FPHA and DBBM group. Conclusions: The incorporation of fluoride ion into PHA could effectively promote the repair of peri-implant bone defects in the early stage of guided bone regeneration.

Comparison of the different voxel sizes in the estimation of peri-implant fenestration defects using cone beam computed tomography: an ex vivo study

BackgroundTo examine the influence of voxel sizes to detect of peri-implant fenestration defects on cone beam computed tomography (CBCT) images.Materials and methodsThis study performed with three sheep heads both maxilla and mandible and two types of dental implant type 1 zirconium implant (Zr40) (n = 6) and type 2 titanium implant (Ti22) (n = 10). A total of 14 peri-implant fenestrations (8 buccal surfaces, 6 palatal/lingual surface) were created while 18 surfaces (8 buccal, 10 palatal/lingual) were free of fenestrations. Three observers have evaluated the images of fenestration at each site. Images obtained with 0.75 mm3, 0.100 mm3, 0.150 mm3, 0.200 mm3, and 0.400 mm3 voxel sizes. For intra- and inter-observer agreements for each voxel size, Kappa coefficients were calculated.ResultsIntra- and inter-observer kappa values were the highest for 0.150 mm3, and the lowest in 0.75 mm3 and 0.400 mm3 voxel sizes for all types of implants. The highest area under the curve (AUC) values were found higher for the scan mode of 0.150 mm3, whereas lower AUC values were found for the voxel size for 0.400 mm3. Titanium implants had higher AUC values than zirconium with the statistical significance for all voxel sizes (p ≤ 0.05).ConclusionA voxel size of 0.150 mm3 can be used to detect peri-implant fenestration bone defects. CBCT is the most reliable diagnostic tool for peri-implant fenestration bone defects.

Accuracy assessment of a novel semiautomatic method evaluating bone grafts around the dental implant: an in vitro and ex vivo study

The present study aimed to evaluate the accuracy and repeatability of morphological contour interpolation (MCI)-based semiautomatic segmentation method for volumetric measurements of bone grafts around dental implants. Three in vitro (one with a cylinder and two with a geometrically complex form) and four ex vivo models (peri-implant cylinder-shaped bone defect) were created for imitating implant placement with simultaneous guided bone regeneration (GBR) procedure. Cone beam computerized tomography (CBCT) scans of all models were obtained with the same parameters. For volumetric measurements, the actual volumes of bone grafts in models were assessed by computer-aided calculation and both manual and MCI-based methods were utilized as test methods. The accuracy of the methods was evaluated by comparing the measured value and the actual volume. The repeatability was assessed by calculating the coefficients of variation of repeated measurements. For the accuracy of three dimensional (3D) reconstructions, the computer-designed corresponding models were set as the reference and the morphological deviation of 3D surface renderings created by two methods were evaluated by comparing with reference. Besides, measurement time was recorded and a comparison between the two methods was performed. High accuracy of the MCI-based segmentation method was found with a discrepancy between the measured value and actual value never exceeding − 7.5%. The excellent repeatability was shown with coefficients of variation never exceeding 1.2%. The MCI-based method showed less measurement time than the manual method and its 3D surface rendering showed a lower deviation from the reference.

Suppuration as diagnostic criterium of peri-implantitis.

Suppuration (SUP) as a diagnostic parameter for monitoring dental implants is not yet well understood. The retrospective clinical and radiographic study was therefore performed to investigate the patient, implant, and site characteristics among individuals exhibiting SUP. Demographic characteristics and clinical parameters were recorded. Radiographic features were analyzed using cone-beam computed tomography. Peri-implantitis was defined based on the consensus report of Workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions: probing depth (PD) ≥6mm, presence of bleeding and/or SUP on gentle probing, and radiographic marginal bone loss (MBL) ≥3mm. SUP was graded according to profuseness (dot versus line/drop) and time after probing (≥15 seconds versus<15 seconds after probing versus spontaneous). Simple binary logistic regression models were estimated using generalized estimation equations to explain the probability of SUP based on demographic, clinical, and radiographic variables. A total of 111 eligible patients (nimplants =501) were assessed. Of them, 57 (nimplants =334) were diagnosed with peri-implantitis according to the established case definition, and of these individuals, 31 (nimplants =96) presented SUP. Therefore, the prevalence of SUP was 27.92% in the total sample size and 54.38% in peri-implantitis patients. Overall, 28.74% implants displayed SUP within patients with peri-implantitis. SUP was more frequently found at buccal sites (51%) and proved less prevalent at mesio-lingual sites (16.7%). Defect morphology (OR=6.59; P=0.004), PD (OR=1.63; P=0.024), and MBL (OR=1.35; P=0.010) were significantly associated with the presence of SUP. Likewise, defect morphology (P=0.02), PD (P=0.003), and MBL (P=0.01) were significantly correlated with the grade of SUP. The presence and grade of SUP are associated with peri-implant bone loss, probing depth, and defect morphology in patients with peri-implantitis.

Cone beam computed tomography artefacts around dental implants with different materials influencing the detection of peri-implant bone defects.

To investigate the diagnostic accuracy of cone beam computed tomography (CBCT) for the diagnosis of peri-implant bone defects of titanium (Ti), zirconium dioxide (ZrO2 ) or titanium-zirconium (Ti-Zr) alloy implants. Ti, Ti-Zr or ZrO2 implants with two diameters (3.3mm, 4.1mm) and one length (10mm) were inserted in the angle of the mandible of six fresh defrosted pig jaws. Out of the 12 implants inserted, 6 served in the test group with standardized buccal peri-implant bone defects, whereas 6 served as control without bone defects. CBCTs were performed with three acquisition protocols (standard, high and low dose) using two devices. Four observers analysed CBCTs as follows: (a) presence of a peri-implant defect; (b) presence of peri-implant artefacts and impact on defect diagnosis; and (c) linear measurements of buccal peri-implant defect including height and width (in mm). CBCT device, CBCT settings, implant material, implant diameter and observer background did not significantly influence diagnostic accuracy. The sensitivity and specificity values were high for defect detection. ZrO2 led to a lower than average diagnostic accuracy (0.781). The linear measurements of peri-implant defect were underestimated by <1mm on average. The subjective impact of artefacts on defect diagnosis was significantly affected by implant material and observer background. CBCT showed high diagnostic accuracy for peri-implant bone defect detection regardless of the device, imaging setting or implant material used. If CBCT is indicated to assess peri-implant bone disease, low dose protocols could be a promising imaging modality.

Effects of Autogenous Tooth Bone Graft and Platelet-Rich Fibrin in Peri-Implant Defects: An Experimental Study in an Animal Model.

The aim of this study was to evaluate the effect of autogenous tooth bone graft (ATBG) combined with platelet-rich fibrin (PRF) on bone healing in rabbit peri-implant osseous defects. Eighteen New Zealand rabbits were divided into 3 groups. Bone defects were prepared in each rabbit, and then an implant cavity was created in the defects. Dental implants were placed, and the peri-implant bone defects were treated with the following 3 methods: no graft material was applied in the control group, bone defects were treated with ATBG in the ATBG group, and bone defects were treated with ATBG combined with PRF in the ATBG+PRF group. After 28 days, the rabbits were sacrificed, and the dental implants with surrounding bone were removed. New bone formation and the percentage of bone-to-implant contact (BIC) were determined with histomorphometric evaluations. New bone formation was significantly higher in the ATBG+PRF group than the control and ATBG groups (P < .05). In addition, BIC was significantly higher in the ATBG+PRF group than in the control and ATBG groups (P < .05). The combination of ATBG with PRF contributed to bone healing in rabbits with peri-implant bone defects.

Neutralized Dicalcium Phosphate and Hydroxyapatite Biphasic Bioceramics Promote Bone Regeneration in Critical Peri-Implant Bone Defects.

The aim of this study was to evaluate the efficacy of bone regeneration in developed bioceramics composed of dicalcium phosphate and hydroxyapatite (DCP/HA). Critical bony defects were prepared in mandibles of beagles. Defects were grafted using DCP/HA or collagen-enhanced particulate biphasic calcium phosphate (TCP/HA/Col), in addition to a control group without grafting. To assess the efficacy of new bone formation, implant stability quotient (ISQ) values, serial bone labeling, and radiographic and histological percentage of marginal bone coverage (PMBC) were carefully evaluated four, eight, and 12 weeks after surgery. Statistically significant differences among the groups were observed in the histological PMBC after four weeks. The DCP/HA group consistently exhibited significantly higher ISQ values and radiographic and histological PMCB eight and 12 weeks after surgery. At 12 weeks, the histological PMBC of DCP/HA (72.25% ± 2.99%) was higher than that in the TCP/HA/Col (62.61% ± 1.52%) and control groups (30.64% ± 2.57%). After rigorously evaluating the healing of biphasic DCP/HA bioceramics with a critical size peri-implant model with serial bone labeling, we confirmed that neutralized bioceramics exhibiting optimal compression strength and biphasic properties show promising efficacy in fast bone formation and high marginal bone coverage in peri-implant bone defects.

Comparison between different cone-beam computed tomography devices in the detection of mechanically simulated peri-implant bone defects.

PurposeThis study compared 2 cone-beam computed tomography (CBCT) systems in the detection of mechanically simulated peri-implant buccal bone defects in dry human mandibles.Materials and MethodsTwenty-four implants were placed in 7 dry human mandibles. Peri-implant bone defects were created in the buccal plates of 16 implants using spherical burs. All mandibles were scanned using 2 CBCT systems with their commonly used acquisition protocols: i-CAT Gendex CB-500 (Imaging Sciences, Hatfield, PA, USA; field of view [FOV], 8 cm×8 cm; voxel size, 0.125 mm; 120 kVp; 5 mA; 23 s) and Orthopantomograph OP300 (Intrumentarium, Tuusula, Finland; FOV, 6 cm×8 cm; voxel size, 0.085 mm; 90 kVp; 6.3 mA; 13 s). Two oral and maxillofacial radiologists assessed the CBCT images for the presence of a defect and measured the depth of the bone defects. Diagnostic performance was compared in terms of the area under the curve (AUC), accuracy, sensitivity, specificity, and intraclass correlation coefficient.ResultsHigh intraobserver and interobserver agreement was found (P<0.05). The OP300 showed slightly better diagnostic performance and higher detection rates than the CB-500 (AUC, 0.56±0.03), with a mean accuracy of 75.0%, sensitivity of 81.2%, and specificity of 62.5%. Higher contrast was observed with the CB-500, whereas the OP300 formed more artifacts.ConclusionWithin the limitations of this study, the present results suggest that the choice of CBCT systems with their respective commonly used acquisition protocols does not significantly affect diagnostic performance in detecting and measuring buccal peri-implant bone loss.

Application of The bFGF and β-TCP Complex to Peri-Implant Bone Defects in Dogs

Application of The bFGF and β-TCP Complex to Peri-Implant Bone Defects in Dogs

Bone Augmentation of Peri-Implant Dehiscence Defects Using Multilaminated Small Intestinal Submucosa as a Barrier Membrane: An Experimental Study in Dogs

Objective The aim of the study is to evaluate the effects of multilaminated small intestinal submucosa (mSIS) combined with bone substitute material to repair peri-implant defects during guided bone regeneration procedures. Methods Twelve implants were placed in bilateral lower premolars of three beagle dogs, and a peri-implant buccal bone defect (3 mm width and 4 mm height) was created at each implant site. A total of 12 sites were filled with a particulate bone substitute material and then randomly divided into three treatment groups: covered by mSIS membrane (mSIS group), covered by collagen membrane (BG group), and no treatment (control group), each group of four sites. After 12 weeks of healing, all of the animals were euthanized and dissected blocks were obtained for micro-computed tomography (micro-CT) and histological analyses. Results Micro-CT results revealed similar horizontal width of augmented tissue and new bone formation between mSIS and BG groups (P < 0.05). Histological analyses revealed that the differences in horizontal widths of newly formed bone and bone-to-implant contact between mSIS and BG groups were not significant (P > 0.05). All of these parameters were significantly different from those in the control group (P < 0.05). Conclusions These findings confirmed that mSIS combined with the bone substitute material enhanced bone regeneration in peri-implant defects, in a manner similar to that of a collagen membrane.

In vitro efficacy of three different implant surface decontamination methods in three different defect configurations

Evaluation of in vitro efficacy of three different implant surface decontamination methods in a peri-implant bone defect model. A total of 180 implants were stained with indelible red color and distributed to standardized peri-implant bone defect resin models with a circumferential defect angulation of 30°, 60°, or 90° (supraosseous defect). Sixty implants were assigned to each type of defect. All implants were cleaned by the same examiner. For each type of defect, 20 implants were cleaned for 2min with one of 3 devices: curette (CUR), sonicscaler (SOSC), or air abrasion with glycine powder (APA). Thereafter, photographs were taken from both sides of each implant and the cumulative uncleaned implant surface area was measured by color recognition technique. Scanning electron micrographs (SEM) were examined to assess morphologic surface damages. The cleaning efficacy as percent (%) of residual color was significantly different for each of the 3 defect angulations (p<0.001) for each treatment device: 30° CUR: 53.44% > SOSC: 19.69% > APA: 8.03%; 60° CUR: 57.13% > SOSC: 11.4% > APA: 0.13%; and 90° CUR: 48.1% > SOSC: 13.07% > APA: 0.58%. The differences between the three different cleaning modalities within each defect type were also significant (p<0.005). SEM micrographs showed no surface damages after the use of APA. Air powder abrasion is the most efficient (APA>SOSC > CUR) and less surface damaging treatment modality for each defect angulation in this in vitro model.

Efficacy of a mineralized collagen bone-grafting material for peri-implant bone defect reconstruction in mini pigs.

The mechanism of the mineralization process induced by natural mineralized collagen (MC) has been investigated for decades. The purpose of this study was to investigate the efficacy of self-assembled MC for peri-implant bone defect reconstruction in a mini pig. A standardized peri-implant bone defect model was created using 14 mini pig mandibles. Two materials were evaluated, i.e. a mixture of hydroxyapatite and collagen (Type A, TA), and self-assembled MC (Type B, TB). Bio-Oss (BO) and untreated (blank control, BC) groups were used as controls. After 3- and 6-month healing periods, the mini pigs were sacrificed for histomorphometric and microcomputed tomography analysis. After 3 months of healing, the average alveolar ridge height was 3.27 ± 1.57 mm for group TA, 3.28 ± 2.02 mm for group TB and 3.37 ± 1.09 mm for group BO, while group BC showed the lowest height of 2.68 ± 0.47 mm. After 6 months of healing, the average alveolar ridge height was 2.64 ± 1.13 mm for group TA, 4.31 ± 1.80 mm for group TB and 3.87 ± 1.38 mm for group BO, while group BC showed the lowest height of 2.48 ± 1.80 mm. The experimental groups and control group showed similar bone volume density, bone complexity and histological reaction. The self-assembled MC (Type B) stimulated new bone formation in the reconstruction of deficient alveolar ridges around the dental implant; it also displayed excellent clinical operability compared with bone grafts without collagen.