A novel micro-CT analysis for evaluating the regenerative potential of bone augmentation xenografts in rabbit calvarias.

Guided Bone Regeneration is a common procedure, yet, as new grafting materials are being introduced into the market, a reliable evaluation method is required. Critical size defect in animal models provides an accurate simulation, followed by histological sections to evaluate the new bone formation. However, histology is destructive, two-dimensional and technique-sensitive. In this study we developed a novel volumetric Micro-CT analysis to quantify new bone formation characteristics. Eight adult female New Zealand white rabbits were subjected to calvarial critical-size defects. Four 8 mm in diameter circular defects were preformed in each animal, to allow random allocation of four treatment modalities. All calvarias were scanned using Micro-CT. Each defect was segmented into four equal parts: pristine bone, outer, middle, and inner. Amira software (v. 6.3, www.fei.com ) was used to calculate the new bone volume in each region and compare it to that of the pristine bone. All grafting materials demonstrated that new bone formation decreased as it moved inward. Only the inner region differed across grafting materials (p = 0.001). The new Micro-CT analysis allowed us to divide each defect into 3D regions providing better understanding of the bone formation process. Amongst the various advantages of the Micro-CT, it enables us to quantify the graft materials and the newly formed bone independently, and to describe the defect morphology in 3D (bi- vs. uni-cortical defects). Providing an insight into the inner region of the defect can better predict the regenerative potential of the bone augmentation graft material. Therefore, the suggested Micro-CT analysis is beneficial for further developing of clinical approaches.

New Bone Growth into Surgical Bone Defects Grafted with a Novel Cultivated Coral Graft: A Histomorphometric Study in Rabbit Calvarias.

Natural Coral Particles (NCPs) are a suitable scaffold material for Guided Bone Regeneration (GBR) procedures; it combines the placement of a bone substitute supporting a barrier membrane. Due to increasing sea pollution and the declarations of endangered coral species (KYOTO 1997), they are no longer suitable for the medical industry. Novel domestic corals have been grown under controlled conditions to produce cultivated coral graft (CCG) material. This study aimed to evaluate a new CCG in an in vivo experimental GBR procedure. The calvarias of 8 rabbits were surgically exposed, and circular defects 8 mm in diameter were prepared. One defect was filled with CCG particles (experimental group); the contralateral defect (control group) was spontaneously filled by blood clot. The defects were covered with a collagen membrane. Animals were euthanized after 8 weeks. Histological observations of the defects showed similar bone growth patterns in both experimental and control osteotomies. In the experimental defects, no traces of coral particles were observed. Histometric analysis showed denser bone in the pristine zone (65-66%) than in the peripheral zone for both the control (50%) and experimental defects (31%) (P= NS). The new bone percentage was reduced from the peripheral zone toward the middle and the center of the defect (31%, 32% and 27%, respectively) as the distance from the peripheral pristine bone borders increased. The existing data support the complete degradation of CCG as space-maintaining scaffold for GBR procedures.

Screw-Type Collar vs. Non-Screw-Type Collar Implants-Comparison of Initial Stability, Soft Tissue Adaptation, and Early Marginal Bone Loss-A Preclinical Study in the Dog.

BACKGROUND: Implant neck characteristics may affect initial implant stability, soft tissue healing, and early marginal bone loss (EMBL) at second-stage surgery. The null hypothesis was that, following two-stage implant insertion, rough surface, non-screw-type collar implants will present lower EMBL at 2nd-stage surgery than rough-surface, screw-type collar implants. METHODS: The study comprised seven male beagle dogs (mean weight 10.57 ± 2.8 kg; range 9-17 kg). A novel implant design was developed, composed of 2 parts: an apical part resembling a regular threaded implant, and a coronal non-screw-type collar, 4.2 mm long, served as the study group, whereas standard threaded implants served as control. Twenty-eight implants were placed: two on each side of the mandible. All implants were sand-blasted/acid-etched and of similar dimensions. Each dog received four implants. To assess location (anterior vs. posterior) impact on the outcomes, implants were placed as follows: group I-posterior mandible right-non-screw-type collar implants; group II-anterior mandible right-similar non-screw-type collar implants. To assess the collar-design effect on the outcomes, implants were placed as follows-Group III-anterior mandible left-control group, screw-type collar implants; Group IV-study group, posterior mandible left-non-screw-type collar implants. The following parameters were measured and recorded: insertion torque, soft tissue healing, early implant failure, and EMBL at 2nd-stage surgery. RESULTS: No statistically significant differences were noted between groups I and II regarding all outcome parameters. At the same time, although insertion torque (55 N/cm) and early implant failure (0) were similar between groups III and IV, group III presented significantly poorer soft tissue healing (1.43 vs. 0.14) and increased marginal bone loss (0.86 vs. 0 mm). CONCLUSIONS: When a two-stage implant protocol was used, rough-surface non-screw-type collar implants led to superior outcomes at 2nd-stage surgery. Implant location did not affect the results. The significance of this result in preventing EMBL awaits further research.

Positive relationship between the dimensions of clinical gingival recessions and associated alveolar bone dehiscences: a biometric study.

OBJECTIVES: To analyze the relationships between the dimension of clinical gingival recession and of the actual bone dehiscence. METHOD AND MATERIALS: Data included measurements taken before and during root coverage surgical procedures. General health, smoking status, previous orthodontic treatment, probing depth, clinical measurements taken on gingival recessions, and the exposed alveolar bone dehiscences were recorded. Data were analyzed using descriptive statistics and linear regression model. RESULTS: Twenty-three patient files were available. The mean age was 31.3 ± 12.1 years (range 13 to 51 years). Eight patients had previous orthodontic treatment. Incisor, canine, and premolar recessions amounted to 9, 8, and 6 teeth, respectively. The deepest recession per patient was recorded. The mean alveolar bone dehiscence depth was 6.78 ± 1.2 mm (range 5 to 9 mm). Patient-related or systemic findings, preceding orthodontic treatment, and tooth type were not correlated with alveolar bone dehiscence dimensions. A significant association was found between clinical recession and the alveolar bone dehiscence depths (P < .001, Fisher exact test). On average, each 1 mm increase in clinical recession depth involved an increase of 1.45 mm in alveolar bone dehiscence depth (P < .001, linear regression). The ratio between the clinical recession depth and width was significantly associated with the depth of the bone dehiscence (P = .007, Fisher exact test). CONCLUSION: Within the limitations of the size of this study, clinical recession depth and width dimensions may help to predict the underling bone dehiscence magnitude. Gingival recession is associated with deformities of the underlying alveolar bone; this may be revealed during mucogingival procedures associated with full-thickness flaps. The association between the two may be of particular value to the operator as it may significantly affect the outcome of treatment. Furthermore, this relationship is of utmost importance in minimally invasive procedures that avoid flap elevation. A significant association was found between the depth of the clinical gingival recession and that of alveolar bone dehiscence. In addition, the ratio between the clinical recession depth and width was significantly associated with the depth of the bone dehiscence. Clinical recession depth and width dimensions may serve as an assessment predictor for the underling bone dehiscence magnitude.

The Incidence and Nature of Claims against Dentists Related to Periodontal Treatment in Israel during the Years 2005-2019.

BACKGROUND: In recent years, worldwide dental malpractice claims have dramatically increased. The purpose of the present study is to analyze periodontal therapy related claims in Israel that led to legal decisions. METHODS: This retrospective cohort study includes malpractice claims against dental practitioners related to periodontology between 2005 and 2019. Only closed cases where a final decision was made were included. The chi-square test or Fisher exact test for categorical variables were performed and a p value of <0.05 was considered statistically significant. RESULTS: During the study period there were 508 legal claims related to periodontal disease. Most plaintiffs were women (63.4%), and 71.3% of the patients were >35 years old. Most claims (82.8%) were settled out of court and ended in compromise. Claims concerning the treatment of periodontal disease by periodontists accounted only for 4.5% (23/508) of the cases while 95.5% (485/508) of the claims were for complications secondary to another treatment. Prosthodontic treatment was involved with the highest number 54.5%, followed by dental implants 17.7%, and endodontics 11.6%. The allegations were related to pain and distress (84.8%), aggravation of existent periodontal disease (83.3%), tooth loss (78.1%), and violation of autonomy (47%). CONCLUSIONS: The main cause for lawsuits was related to aggravation of periodontal disease during prosthetic or implant therapy and related to suspected faulty or inexistent preoperative diagnosis and planning. PRACTICAL IMPLICATIONS: Periodontal consultation before dental treatment may reduce malpractice risks, adverse events, and un-necessary changes of treatment plans.

Effects of peri-implant infection on serum biochemical analysis.

BACKGROUND: Peri-implant disease (PID) has not been directly linked to pathological organ changes. The present study assessed the dynamics of serum biochemical parameters in a model of experimental peri-implantitis in dogs, followed by open flap debridement. METHODS: Seven male beagle dogs comprised the study group. Procedures were performed as follows-extractions of two premolars and one molar on each mandibular quadrant (Day 0); bone healing time (week14); placement of four rough-surface endoosseous implants, two on each mandibular side; implant uncovering (week 28); induction of experimental peri-implantitis by the use of three ligatures (weeks 31, 34, 37) followed by open flap debridement (week 42). Serum biochemical analysis following each procedure was compared to baseline. Biochemical parameters were assigned into four subsets of variables-inflammation, renal function, liver function, and blood glucose. Wilcoxon paired tests were conducted in order to identify statistically significant differences between baseline data and values obtained after each procedure RESULTS: Following experimental peri-implantitis, the dynamics of renal parameters and blood glucose were minimal whereas statistically significant (P < 0.05) increases were noted for inflammatory (total protein and albumin concentrations) and hepatic (ALT, AST) parameters. A statistically significant (P < 0.05) decrease was only noted for total bilirubin. After open flap debridement, inflammatory (total protein and albumin concentrations) and hepatic (AST) parameters returned to baseline. CONCLUSIONS: Within their limits, the present results indicate that: (a) PID affects inflammatory and hepatic serum biochemical parameters, and (b) following open flap debridement most of the values returned to baseline.

Peri-implant disease affects systemic complete blood count values-an experimental in vivo study.

OBJECTIVES: To assess complete blood count (CBC) dynamics following ligature removal and open flap debridement in experimental peri-implantitis in dogs. MATERIALS AND METHODS: Seven male beagle dogs were included in the study. Four rough-surface implants were placed pair-wise in both sides of the mandible 14 weeks after tooth extraction. Second stage surgery was performed after 14 weeks. Experimental peri-implantitis was initiated 3 weeks later by ligature placement around the healing caps thus facilitating plaque accumulation and inducing inflammation and destruction of peri-implant tissues. Ligature removal and open flap debridement were performed 11 weeks later. The CBC values were compared with baseline after each procedure. Wilcoxon paired tests were conducted in order to identify statistically significant differences between baseline data and values obtained after each procedure. RESULTS: Following experimental peri-implantitis, statistically significant (p < 0.05) increases were noted for white blood cells-WBC (9.62 ± 4.34 vs. 6.48 ± 1.34 cells per microliter of blood × 1000), hemoglobin-Hb (15.25 ± 0.94 vs. 13.52 ± 1.46, grams per deciliter), red blood cells-RBC (7.26 ± 0.79 vs. 5.9 ± 0.61 cells per microliter of blood × 1000), mean corpuscular hemoglobin-MCH (23.64 ± 0.96 vs. 23.16 ± 0.83 picograms/cell), platelets-PLT (349.86 ± 51.05 vs. 277.57 ± 66 cells per microliter of blood × 1000), and mean corpuscular hemoglobin concentration-MCHC (35.83 ± 0.27 vs. 31.04 ± 0.48 grams per deciliter). A statistically significant (p < 0.05) decrease in values was noted only for after ligature removal and open flap debridement. Mean corpuscular volume-MCV values were significantly lower (65.99 ± 2.31 vs. 74.65 ± 2.85 femtoliter) following 1st ligature. Values returned to baseline after open flap debridement. CONCLUSIONS: Within its limits, the present data suggest that experimentally induced peri-implantitis affects CBC values. Following surgical treatment, CBC values returned to normal. Clinical relevance This is the first study suggesting possible relationships between peri-implantitis and CBC values. Future studies, confirming such correlation, may provide an insight into the importance of peri-implant maintenance and treatment to minimize supporting tissues disease and reduce systemic effects.

Allograft and Collagen Membrane Augmentation Procedures Preserve the Bone Level around Implants after Immediate Placement and Restoration.

Background: Immediate implant placement and restoration (IPR), is a reliable treatment modality. Purpose: This historical prospective study evaluated the medium-term outcomes of hard tissue after IPR in the anterior maxilla with simultaneous hard tissue augmentation. Methods: Seventy-three patients treated with single-implant IPR in the anterior maxilla were followed for 1-8 years. Treatment involved, atraumatic extraction, immediate implant placement and abutment adaptation, followed by simultaneous augmentation with mineralized freeze-dried bone allograft (FDBA) particles to fill the gaps and restore the ridge. The surgical site was stabilized with a resorbable collagen membrane, followed by the connection of an acrylic provisional restoration. Results: All implants osseointegrated during the follow-up period (mean, 34 ± 22 months). Radiographic evaluation of the distance between the implant shoulder (IS) and crestal bone level (CBL) was of 0.86 ± 0.86 mm and 0.8 ± 0.84 mm mesially and distally, respectively. Splitting the results into up to 3 years and 3-8 years of follow-up data, the corresponding values were 0.90 ± 0.83 and 0.68 ± 0.88 for the mesial aspect and 0.99 ± 0.87and 0.74 ± 0.83 for the distal aspect, respectively. Mean peri-implant probing depth was 3.63 mm (SD ± 1.06) and 16 implants (22%) presented at least one bleeding pocket of ≥5 mm (peri implant mucositis). Conclusions: The immediate replacement of a single maxillary tooth by implants combined with guided bone regeneration is a predictable treatment modality with favorable peri-implant bony response.

Tensile Properties of Three Selected Collagen Membranes.

BACKGROUND: Biological barriers are commonly used to treat alveolar bone defects and guide tissue regeneration. Understanding the biological and mechanical properties of the available membranes is crucial for selecting the one that is optimal for enhancing clinical outcomes. PURPOSE: To evaluate the mechanical behavior of three different collagen membranes to increasing tensile force in dry and wet conditions. MATERIALS AND METHODS: Three commercially collagen membranes were selected for analysis: Bio-Gide® (Geistlich Biomaterials, Baden-Baden, Germany), Remaix™ (RX; Matricel GmbH, Herzogenrath, Germany), and Ossix Plus® (Datum Dental Biotech, Lod, Israel). Increasing tensile forces were applied on 10 dry and wet membranes of standard size via a loading machine. Force and extension values were acquired up to maximum load before failure, and maximum stress, maximum extension, and amount of energy needed for membrane tearing were analyzed. Membranes' densities were also calculated. RESULTS: The Remaix membrane exhibited the highest values of maximum load tensile strength, maximum extension, and maximum energy required for membrane tearing, followed by Bio-Gide. Ossix Plus had the lowest scores in all these parameters. Dry membranes had the highest scores for all parameters except extension. Membrane density was directly and significantly correlated with all tested parameters. CONCLUSIONS: The study was undertaken to provide clinicians with data upon which to base the selection of collagen membranes in order to achieve optimal clinical results. It emerged that the mechanical properties of dry and wet collagen membranes were significantly different from one another. Among the 3 tested membranes, Remaix exhibited higher performance results in all the mechanical tests. Collagen membrane density seems to have a significant influence upon mechanical resistance. These findings may also guide manufacturers in improving the quality of their product.

Correction to: Sinus augmentation analysis of the gradient of graft consolidation: a split-mouth histomorphometric study.

Figure 1 was reused with permission from "Wiley", the publisher of a previous article by the same authors, DOI:10.1111/cid.12518.

Sinus augmentation analysis of the gradient of graft consolidation: a split-mouth histomorphometric study.

OBJECTIVE: The aim of this study was to histomorphometrically test the hypothesis that graft consolidation originates from the sinus floor. MATERIALS AND METHODS: This prospective, randomized split-mouth study investigated patients undergoing bilateral maxillary lateral sinus floor augmentation using either freeze-dried bone allografts (FDBAs) or biphasic calcium phosphate (BCP) bone substitute. Apico-coronal core biopsies were harvested during implant placement 9 months after sinus floor augmentation, processed for histological observation, and measured histomorphometrically. RESULTS: Biopsies were taken from 26 bilateral sites in 13 patients. The density of new bone (NB) decreased with increasing distance from the sinus floor. The percentage mean surface of NB ranged from 31 ± 9.5% at 2 mm from the sinus floor (G1) to 27.7 ± 11.2% at 4 mm (G2) for the FDBA specimens and from 30.0 ± 11.0% at G1 to 23.5 ± 9.9% at G2 for the BCP specimens. Evaluation of the residual graft particle (GP) area alone as a function of distance from the floor revealed a clear inverse gradient of 7.1 ± 6.6 to 9.1 ± 10.3 between G1 and G2 for the FDBA allografts, with the same tendency for the BCP alloplasts (21.9 ± 9.9 to 27.7 ± 6.6, respectively). CONCLUSION: Our results support the concept that osteogenesis initiates in regions proximal to the bony walls of the maxillary sinus and may be enhanced by them. CLINICAL RELEVANCE: The nature of the grafting material had a greater influence on the degree of NB formation in regions distant from the native walls where there is reduced inherent osteogenic potential.

Direct Contact Test for Evaluating Bacterial Growth on Machined and Rough Surface Implants: An In Vitro Study.

OBJECTIVE: To use a modified direct contact test (DCT) to evaluate the bacterial growth on 3 commercially available implants. MATERIALS AND METHODS: Streptococcus salivarius growth was tested on 1 machined surface and 2 commercial rough surface implants. Seven implants from each group were fixed to the cover of a 96-well microtiter plate. Bacterial suspension was placed on each implant, and the plate was incubated at 37°C for 1 hour to allow the suspension fluid to evaporate. Fresh medium was added to 7 corresponding wells in the microtiter plate, and the cover holding the implants was placed on the plate to enable immersion of the implant. Noncontaminated implant samples served as control. Bacterial growth was monitored spectrophotometrically at 650 nm for 24 hours. RESULTS: There was a significant S. salivarius growth in all groups of test implants compared with the control. There was no significant difference between bacterial growth kinetics on treated and nontreated implant surfaces (P = 0.241). CONCLUSION: Using the DCT, we found no difference in bacterial growth between machined and rough surface implants.

Comparison between mineralized cancellous bone allograft and an alloplast material for sinus augmentation: A split mouth histomorphometric study.

BACKGROUND: Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone, hydroxyapatite, ß-tricalcium phosphate, anorganic deproteinized bovine bone, and combination of these and others. Yet, the issue of the optimal graft material for sinus floor augmentation is controversial. PURPOSE: This prospective, randomized split-mouth study was undertaken to histomorphometrically compare a biphasic calcium phosphate (BCP) alloplastic bone substitute and a human bone mineral allograft (freeze-dried bone allograft, FDBA) in patients undergoing bilateral maxillary lateral sinus floor augmentation. MATERIAL AND METHODS: Apico-coronal core biopsies were harvested at 9 months from 26 bilateral sites in 13 treated patients. Specimens were processed for histological and histomorphometrical analyses. RESULTS: Newly formed bone (NB) was evident in all specimens with values of 27.5% and 24.0% at the FDBA and BCP sites, respectively (P = .331). The residual graft particle values were 12.5% and 25.4% (P = .001), and the connective tissue values were 60.0% and 50.6%, respectively. The osteoconductive value was 52.6% for the FDBA and 26.7% for the alloplast (P = .001). The values for the measured residual graft particles, connective tissue, and osteoconductivity, but not for NB, showed highly significant differences between the two groups. All sections in the alloplast material showed evidence of a light chronic inflammatory infiltrate, mainly comprising lymphocytes and multinucleated giant cells. CONCLUSIONS: Both graft materials are suitable for sinus floor augmentation, with the allograft material being more osteoconductive.

Bone-to-Implant Contact and New Bone Formation Within Human Freeze-Dried Bone Blocks Grafted Over Rabbit Calvaria.

PURPOSE: To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria. MATERIALS AND METHODS: A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis. RESULTS: All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2). CONCLUSION: In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.

Esthetic Assessment of Implants Placed into Fresh Extraction Sockets for Single-Tooth Replacements Using a Flapless Approach.

BACKGROUND: To validate the concept of immediate implant placement and nonfunctional loading for use in the esthetically sensitive anterior maxilla, clinical trials should ideally include objective esthetic criteria. PURPOSE: This study analyzed procedural results as graded by the pink esthetic score and white esthetic score (PES/WES). METHODS: Thirty-nine suitable patients (mean follow-up 44.82 ± 28 months) were evaluated. RESULTS: Thirty-eight implants fulfilled stringent criteria for successful osseointegration: absence of peri-implant radiolucency, implant mobility, suppuration, and pain. The mean total PES/WES was 15.50 ± 2.67 (range: 10-20). The mean total PES of 7.92 ± 1.60 (range: 5-10) indicated favorable overall peri-implant soft-tissue conditions. Root convexity and texture (1.63 ± 0.54) and curvature of the facial mucosa (1.68 ± 0.47) and distal papilla (1.66 ± 0.48) had the highest mean values, whereas acceptable levels of facial tissue (1.53 ± 0.73) and mesial papilla (1.42 ± 0.64) were the most difficult to fully achieve. The mean mesial and distal bone loss at data collection was, was 1.19 ± 0.54 and 1.15 ± 0.51, respectively. Periodontal disease severity (advanced chronic and aggressive periodontitis) was significantly associated with a low total PES (p = .048). CONCLUSIONS: Objective PES/WES assessment validated immediate anterior maxillary single-tooth replacement and restoration as being a successful and esthetically predictable treatment modality in sites where the buccal bone had been preserved during the extraction at 1 year of follow-up.

Clinicopathologic evaluation of malignancy adjacent to dental implants.

OBJECTIVE: The aim of this study was to describe a new case series of peri-implant malignancy, review the literature, and discuss the implications of malignancies resembling peri-implantitis. STUDY DESIGN: This study was a retrospective analysis of cases from 2000 to 2016. RESULTS: Seven patients (two males and five females), aged 44 to 89 years, were included, representing 1.5% of oral malignancy cases. Five cases were squamous carcinoma, one of basal cell carcinoma, and one of carcinoma of metastatic origin. Six cases presented with nonulcerated overgrowth, with bone loss in three and massive osteolysis in one. Misinterpretation as peri-implantitis delayed diagnosis in six cases. Risk factors included previous oral malignancy (2), potentially malignant conditions (2), and smoking (1). Of the 47 cases in the English language literature, 85% were squamous cell carcinoma and 8.5% had distant metastasis. Most cases had one or more risk factors. CONCLUSIONS: Peri-implant malignancy may represent up to 1.5% of oral malignancy cases. Clinical features imitating peri-implantitis may delay diagnosis. Lesions failing to respond to treatment, especially in patients with pre-existing risk factors, should significantly increase suspicion. Histopathology is crucial for diagnosis.

Radiological and Biological Assessment of Immediately Restored Anterior Maxillary Implants Combined with GBR and Free Connective Tissue Graft.

OBJECTIVES: Radiologic and biologic assessment of immediately restored Implants combined with guided bone regeneration (GBR) and free connective tissue graft. METHODS: 1-4 year retrospective study involving 34 patients treated with maxillary immediately restored anterior single-implants. Soft tissue dimensions, radiographic bone loss, and biological and prosthetic complications were assessed. RESULTS: During the mean follow up period of 29 months the study group presented a mean mesial bone loss of 1.10 ± 0.39 mm (range: 0.5-2.4 mm), and mean distal bone loss of 1.19 ± 0.41 mm (range: 0.4-2.1 mm). Mean periimplant probing depth of 3.49 mm (SD ± 1.06) and 2.35 (SD ± 0.52) for the contralateral tooth (highly significant p < 0.001). Bleeding on probing was present in 29.4% of the examined implant supported crown sites and 10.4% of the contralateral teeth (p < 0.001). CONCLUSIONS: Anterior maxillary single-tooth replacement, using GBR and connective tissue graft according to the concept of immediate implant placement, and non-functional restoration is an accepted treatment modality achieving favorable peri-implant soft tissue condition.

Differences in crestal bone-to-implant contact following an under-drilling compared to an over-drilling protocol. A study in the rabbit tibia.

OBJECTIVES: The objective of this study is to compare bone-to-implant contact (BIC) between implants inserted at high torque due to under-drilling of the crestal bone to those inserted at low torque due to over-drilling of the crestal bone. MATERIALS AND METHODS: Forty implants with diameters of 3.75 mm (group A) or 3.55 mm (group B) were inserted in the proximal tibiae of NZW rabbits in two separate surgeries on day 0 or 21. Osteotomy of the crestal bone was finalized with a 3.65-mm drill. In group A, implants were inserted at torque ≥35 Ncm (under-drilling) and in group B with torque <10 Ncm (over-drilling). Implants and their surrounding bone were retrieved on day 42, thus creating 3- and 6-week observation periods, processed for non-decalcified histology and stained with toluidine blue. Crestal BIC (c-BIC) and total BIC (t-BIC) were measured. Wilcoxon test was used to evaluate differences between groups. RESULTS: Three weeks post-surgery, the mean c-BIC in group A was 16.3 ± 3.3 vs 31.5 ± 3.4 % in group B (P < 0.05). At 6 weeks, a similar trend was observed (group A: 28.7 ± 3.6 %; group B: 38.4 ± 4.9 %) (P > 0.05). No differences in t-BIC were noted at 3 weeks and at 6 weeks between the groups. CONCLUSIONS: Insertion of implants with an over-drilling protocol of the crestal aspect of the osteotomy resulted in increased short-term crestal bone-to-implant contact. CLINICAL RELEVANCE: Insertion of implants with a high torque following an under-drilling protocol, commonly used for immediate loading, may reduce crestal bone-to-implant contact at early healing stages.

Esthetic assessment of immediately restored implants combined with GBR and free connective tissue graft.

AIM: Esthetic assessment of immediately restored implants combined with GBR and free connective tissue (CT) graft METHODS: A case-control, retrospective study involving 34 patients treated with maxillary anterior single implants, immediately placed and restored. Clinical and esthetic results were analyzed using standard clinical examination and a comprehensive index, comprising pink esthetic and white esthetic scores (PES/WES). The height of the implant crown and the corresponding height of the contralateral tooth crown were measured to identify mucosal recessions. The distance from the mucosal margin to the implant shoulder (DIM) was measured on the master model. RESULTS: Thirty of 34 implants fulfilled the strict success criteria set for dental implants with regard to osseointegration. Success was defined as implants with bone loss not exceeding 1.5 mm during the first year and loosing not more than 0.2 for each successive year. The other four implants were stable but did not meet the bone loss criteria mentioned above and defined as survived implants. Mean PES/WES was 14.44 ± 2.34 (range: 9-20). Mean PES was 7.12 ± 1.89 (range: 1-10). The highest mean values were achieved for the variable of root convexity/soft tissue color and texture (1.71 ± 0.46) whereas the mesial papilla (1.09 ± 0.62) proved to be the least pleasing. The mean WES was 7.32 ± 1.25 (range: 5-10). The difference between IC and contralateral TC was 0.54 mm. The mean value for the facial DIM was 3.82 ± 0.87 mm. CONCLUSIONS: An evaluation of soft and hard tissue augmentation in immediately restored immediate implant procedures was employed to obtain stable hard and soft tissues. The combined GBR and CT graft procedure achieved favorable peri-implant soft tissue condition and esthetic results. However, recession and incomplete papillas were frequently observed.

Accelerated degradation of collagen membranes in diabetic rats is associated with increased infiltration of macrophages and blood vessels.

OBJECTIVES: Increased collagenolytic activity in diabetes may compromise collagen membrane (CM) survival. Tetracycline (TTC) possesses anti-collagenolytic properties and delays CM degradation. This study evaluated macrophage and capillary infiltration within CMs in diabetic rats. MATERIALS AND METHODS: Diabetes was induced in 20 Wistar rats by streptozotocin and 20 served as controls. Biotin-labeled CM discs were immersed in either TTC (50 mg/ml) or PBS. In each animal, 2 discs (TTC and control) were implanted under the parietal periosteum and rats were sacrificed at 2 or 4 weeks post-implantation. The area and thickness of the residual disc collagen were measured following staining with streptavidin, and the number of macrophages and blood vessels within the membranes was determined using specific antibodies (to CD68 and transglutaminase II, respectively). RESULTS: Diabetes significantly reduced the area and thickness of the CMs, while TTC increased CM thickness significantly in both groups of rats at 2 and 4 weeks. Diabetes increased the number of macrophages (∼eightfold at 2 weeks and ∼fourfold at 4 weeks), but TTC had no significant effect. Finally, diabetes increased the number of blood vessels within the discs (∼threefold at 2 weeks and ∼twofold at 4 weeks), while TTC had no effect. CONCLUSIONS: Diabetes increases degradation of native CMs and the number of blood vessels and macrophages within them. TTC immersion delays CM degradation without an apparent effect on macrophage and blood vessel penetration. CLINICAL RELEVANCE: Enhanced CM degradation in diabetic conditions which impair guided regenerative procedure outcome is apparently related to increased blood vessel formation and macrophage infiltration.