The combination of purified recombinant human platelet-derived growth factor-BB and equine particulate bone graft for periodontal regeneration

Background: The objective of this study is to evaluate the potential for periodontal regeneration of a critical‐sized defect with the application of recombinant human platelet‐derived growth factor (rhPDGF‐BB) combined with either a particulate equine or a β‐tricalcium phosphate (β‐TCP) matrix. Methods: Critical‐sized intrabony 2‐wall defects were created bilaterally on the distal surface of the second premolar and the mesial surface of the first molar in nine hounds. Twelve defects received rhPDGF‐BB/equine treatment, 12 defects received rhPDGF‐BB/β‐TCP treatment, and the remaining 12 sites served as sham‐surgery controls. The animals were sacrificed after a 10‐week healing period. Results: Clinical healing was uneventful without obvious signs of overt gingival inflammation. Histologic and histomorphometric analyses revealed statistically that there were differences among the three groups in terms of new bone formation (P <0.001). The amount of test material for both rhPDGF‐BB/equine and rhPDGF‐BB/β‐TCP groups was comparable, but the amount of newly formed bone was significantly higher (P <0.01) in favor of the rhPDGF‐BB/equine group. The amount of new cementum formed for the rhPDGF‐BB/equine group (4.8 ± 1.3 mm) was significantly higher (P =0.001) than the sham‐surgery control group (1.7 ± 1.9 mm). Conclusion: Both rhPDGF‐BB/equine and rhPDGF‐BB/β‐TCP have the potential to support the regeneration of the periodontal attachment apparatus.     

Clinical efficacy of autogenous dentin grafts with guided bone regeneration for horizontal ridge augmentation: a prospective observational study

The aim of this study was to evaluate the efficacy of autogenous dentin grafts with guided bone regeneration (GBR) for horizontal ridge augmentation. Nineteen patients with dentition and bone defects in whom tooth/teeth extraction was indicated were recruited. Autogenous teeth were prepared, fixed on the buccal sides of the defects, and covered with bone powder and resorbable membranes before implantation. The horizontal bone mass at 0 mm (W1), 3 mm (W2), and 6 mm (W3) from the alveolar crest was recorded using cone beam computed tomography, before, immediately after, and 6 months after dentin grafting. All adverse effects were recorded. The implant stability quotient (ISQ) was measured 6 months after implantation. Twenty-eight implants were placed 6 months after dentin grafting. At this time point, the bone mass was 4.72 ± 0.72 mm (W1), 7.35 ± 1.57 mm (W2), and 8.96 ± 2.38 mm (W3), which was significantly different from that before the surgery (P < 0.05). The bone gain was 2.50 ± 0.72 mm (W1), 4.10 ± 1.42 mm (W2), and 4.56 ± 2.09 mm (W3). No soft tissue dehiscence or infection was observed. Overall, 26.3% of the patients experienced severe pain after dentin grafting. The ISQ was 78.31 ± 6.64 at 6 months after implantation. Autogenous tooth roots with GBR might be effective for horizontal ridge augmentation. This technique could be an alternative to augmentation using autogenous bone grafts.     

Guided bone regeneration in standardized calvarial defects using beta-tricalcium phosphate and collagen membrane: a real-time in vivo micro-computed tomographic experiment in rats

Guided bone regeneration (GBR) procedures using graft materials have been used for reconstruction of osseous defects. The aim of the present in vivo micro-computed tomographic (µCT) and histologic study was to assess in real time the bone regeneration at GBR sites in standardized experimental calvarial defects (diameter 3.3 mm) using β-tricalcium phosphate (β-TCP) with and without collagen membrane (CM). A single full-thickness calvarial defect was created on the left parietal bone in young female Wistar albino rats (n = 30) weighing approximately 300 g and aged about 6 weeks. The animals were randomly divided into three groups for treatment, based on calvarial defect filling material: (1) control group (n = 10); (2) β-TCP + CM group (n = 10); (3) β-TCP group (n = 10). Real-time in vivo µCT analyses were performed immediately after surgery and at 2, 4, 6 and 10 weeks to determine the volume and mineral density of the newly formed bone (BVNFB, MDNFB) and remaining β-TCP particles (VRBP, MDRBP). The animals were killed at 10 weeks and calvarial specimens were evaluated histologically. In the control group, MDNFB increased significantly at 6 weeks (0.32 ± 0.002 g/mm³, P < 0.01) compared to that at baseline. In β-TCP + CM group, BVNFB (1.10 ± 0.12 mm³, P < 0.01) and MDNFB (0.13 ± 0.02 g/mm³, P < 0.01) significantly increased at the 4th week than baseline. In the β-TCP group, BVNFB (1.13 ± 0.12 mm³, P < 0.01) and MDNFB (0.14 ± 0.01 g/mm³, P < 0.01) significantly increased at 6 weeks compared to that at baseline. Significant reduction in VRBP was neither seen in the β-TCP + CM group nor in the β-TCP group. While in the β-TCP + CM group MDRBP was reduced significantly at 6 weeks (0.44 ± 0.9 g/mm³, P < 0.01) from baseline (0.98 ± 0.03 g/mm³), similar significant reduction in MDRBP from baseline (0.92 ± 0.07 g/mm³) was seen only at 10 weeks (0.45 ± 0.06 g/mm³, P < 0.05) in the β-TCP group. Histologic findings at 10 weeks revealed greater amount of NFB with osteocytes in the matrix, in the β-TCP + CM group than in the β-TCP group. Biomechanical assessment of NFB for hardness (H) and elastic modulus (E) revealed significantly higher values for the β-TCP + CM group (H = 612.6 ± 4.28 Mpa; E = 13.57 ± 0.07 Gpa) when compared to those of the control (H = 192.1 ± 4.93 Mpa; E = 6.76 ± 0.04 Gpa) and the β-TCP groups (H = 241.9 ± 6.29 Mpa; E = 4.34 ± 0.06 Gpa). In conclusion, based on real-time assessment, NFB is formed in calvarial defects as early as 4 weeks following GBR with β-TCP + CM as compared to 6 weeks when β-TCP alone was used.     

Evaluation of a platform-switched Morse taper connection for all-on-four or six treatment in edentulous or terminal dentition treatment: A retrospective study with 1–8 years of follow-up

Background

The survival rate, marginal bone loss and soft tissue health of the Ankylos implants and the balanced base abutments in all-on-four or six implant restoration of edentulous or terminal dentition patients has not been reported in the clinical research.

Purpose

This retrospective study aimed to evaluate the Ankylos implants and the balanced base abutments in all-on-four or six implant restoration of edentulous or terminal dentition patients after 1–8 years of follow-up.

Materials and Methods

A retrospective study was conducted based on the medical records of 33 patients who received all-on-four or six treatments from April 2014 to May 2020. Four radiographic examinations [immediate postoperative (T0), definitive restorations (T1), 1–3 years after prosthetic restorations (T2), and more than 3 years after prosthetic restorations (T3)] were obtained to evaluate vertical bone height (VBH). We also calculated the survival rate and examined the condition of soft tissue with this implant system in edentulous or terminal dentition patients. Three-level linear model analyses were used to explore potential risk factors for VBH changes on the mesial and distal sides. The generalized linear model was used to analyze the influencing factors of BOP and plaque.

Results

A total of 218 implants were included in this study. The cumulative survival rate of the implants was 97.25% before the definitive prosthesis, 96.33% within 3 years of follow-up and 95.32% after more than 3 years of follow-up. The mean ± standard deviation (SD) bone losses of the VBH were 0.27 ± 0.05 mm (T1-T3) on the mesial side and 0.49 ± 0.06 mm (T1-T3) on the distal side. During 1–8 years of follow-up, the height and angle of the abutment (p < 0.001), the mandible implant site (p < 0.001), the length of the implant (p = 0.014 < 0.05) and age (p = 0.029 < 0.05) showed statistically significant effects on vertical mesial bone height (VMBH) and vertical distal bone height (VDBH). The risk of BOP among participants who brushed three times a day was lower than those who brushed less than three times. The plaque risk of short abutment height was higher than the long abutment.

Conclusion

The current study showed that the Ankylos implants with the balanced base abutments in all-on-four or six implants treatment is a viable and predictable option with a high survival rate and low marginal bone loss in edentulous or terminal dentition patients. VBH around the implants was strongly associated with the mandible implant site, abutment height and angle, the length of the implant and age. Moreover, teeth-brushing times and abutment height significantly affect soft tissue health.     

Correction of Buccal Dehiscence During Immediate Implant Placement Using the Flapless Technique: A Tomographic Evaluation

Background: The aim of this study was to evaluate a new technique for treating dehiscence buccal bone sites (Class II) with immediate implant and collagen‐enriched bovine‐derived xenograft blocks without a surgical flap or membrane. Methods: Individuals with at least 5 mm of buccal bone dehiscence were selected for a flapless surgical approach to insert xenograft blocks into buccal dehiscence defects as well as the gap between implant and residual bone wall. No membrane was used. Buccal bone wall height was measured by computed tomography in the preoperative period (T0) and 6 to 12 months after procedure (T1). Likewise, buccal‐lingual width of alveolar ridge as well as thickness of buccal wall was compared with the contralateral tooth. Results: Fourteen patients were selected. Buccal wall height at T1 was not significantly different after 6 to 12 months between the treated and contralateral teeth, although both were greater than T0 (P <0.01). The heights ranged from 6.4 to 16.30 mm at T0, 12.8 to 25.6 mm at T1, and 14.8 to 25.29 mm in the contralateral teeth. Significant differences were observed between treated teeth (T1) and their contralateral, both buccal‐lingually in the alveolar ridge (P = 0.007) and in buccal wall thickness (P = 0.003). Wall thickness ranged from 0.9 mm to 3.81 mm at T1 and 0.25 mm to 1.60 mm in the contralateral teeth. Conclusion: Immediate implant placement at dehiscence buccal bone sites using flapless surgery combined with xenograft blocks provided complete formation of the buccal bone wall up to the implant shoulder.     

Ridge Preservation Comparing Socket Allograft Alone to Socket Allograft Plus Facial Overlay Xenograft: A Clinical and Histologic Study in Humans

Background: Previous studies of ridge preservation showed a loss of ≈18% or 1.5 mm of crestal ridge width in spite of treatment. The primary aim of this randomized, controlled, masked clinical trial is to compare a socket graft to the same treatment plus a buccal overlay graft, both with a polylactide membrane, to determine if loss of ridge width can be prevented by use of an overlay graft. Methods: Twelve patients who served as positive controls received an intrasocket mineralized cancellous allograft (socket group), and 12 patients received the same socket graft procedure plus buccal overlay cancellous xenograft (overlay group). Horizontal ridge dimensions were measured with a digital caliper, and vertical ridge changes were measured from a stent. Before implant placement, at 4 months, a trephine core was obtained for histologic analysis. Results: The mean horizontal ridge width at the crest for the socket group decreased from 8.7 ± 1.0 to 7.1 ± 1.5 mm for a mean loss of 1.6 ± 0.8 mm (P <0.05), whereas the same measurement for the overlay group decreased from 8.4 ± 1.4 to 8.1 ± 1.4 mm for a mean loss of 0.3 ± 0.9 mm (P >0.05). The overlay group was significantly different from the socket group (P <0.05). Histologic analysis revealed that the socket group had 35% ± 16% vital bone, and the overlay group had 40% ± 16% (P >0.05). Conclusions: The overlay treatment significantly prevented loss of ridge width and preserved or augmented the buccal contour. The socket and overlay groups healed with a high percentage of vital bone.     

Additive Effect of Plasma Rich in Growth Factors With Guided Tissue Regeneration in Treatment of Intrabony Defects in Patients With Chronic Periodontitis: A Split‐Mouth Randomized Controlled Clinical Trial

Background: Periodontal regeneration can be defined as complete restoration of lost periodontal tissues to their original architecture and function. A variety of treatment modalities have been proposed to achieve it. Plasma rich in growth factors (PRGF) is a concentrated suspension of growth factors that promotes restoration of lost periodontal tissues. The objective of the present study is to assess the effect of PRGF associated with guided tissue regeneration (GTR) versus GTR only in the treatment of intrabony defects (IBDs) in patients with chronic periodontitis (CP). Methods: Patients with CP (n = 14) with 42 contralateral 2‐ and 3‐walled defects were randomly assigned to test (PRGF+GTR) and control (GTR alone) treatment groups. Clinical and radiographic assessments performed at baseline and after 6 months were: 1) gingival index (GI), 2) probing depth (PD), 3) clinical attachment level (CAL), 4) radiologic defect depth, and 5) bone fill. Results: Comparison of parameters measured at baseline and after 6 months showed mean PD reduction of 3.37 ± 1.62 mm in the control group (P <0.001) and 4.13 ± 1.59 mm in the test group (P <0.001). There was a significant difference in mean change in CAL (P <0.001) in the control group (5.42 ± 1.99) and the test group (5.99 ± 1.77). Mean change in GI was 1.89 ± 0.32 and 1.68 ± 0.58 in the control group and test group, respectively, and the difference was statistically significant (P <0.001). When compared between groups, clinical parameters did not show any statistically significant variations. Mean radiographic bone fill was 1.06 ± 0.81 and 1.0 ± 0.97 in the control group and test group, respectively. However, the difference was not statistically significant. Conclusions: PRGF with GTR, as well as GTR alone, was effective in improving clinical and radiographic parameters of patients with CP at the 6‐month follow‐up. There was no additive effect of PRGF when used along with GTR in the treatment of IBDs in patients with CP in terms of both clinical and radiologic outcomes.     

Whole Salivary Interleukin‐6 and Matrix Metalloproteinase‐8 Levels in Patients With Chronic Periodontitis With and Without Prediabetes

Background: The cytokine profile in unstimulated whole saliva (UWS) of patients with prediabetes and chronic periodontitis (CP) remains uninvestigated. The aim of this study is to assess interleukin (IL)‐6 and matrix metalloproteinase (MMP)‐8 levels in UWS of patients with CP with and without prediabetes. Methods: Eighty‐eight males (aged 39 to 51 years) were divided into three groups: group 1: 28 patients with CP and prediabetes; group 2: 30 patients with CP and without prediabetes; and group 3: 30 controls. Fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels, periodontal parameters (plaque index, bleeding on probing, probing depth, attachment loss, and marginal bone loss), and number of missing teeth were recorded. UWS samples were collected, and UWS flow rate (UWSFR) was measured. IL‐6 and MMP‐8 were measured in UWS using enzyme‐linked immunosorbent assay. P values <0.05 were considered statistically significant. Results: Mean FBG and HbA1c levels were significantly higher in group 1 (119.3 ± 3.1 mg/dL and 6.1% ± 0.2%) than group 2 (80.1 ± 3.5 mg/dL and 4.8% ± 0.5%; P <0.001) and group 3 (75.3 ± 2.2 mg/dL and 4.3% ± 0.2%; P <0.05). UWSFR was significantly higher in groups 2 (0.53 ± 0.1 mL/minute; P <0.05) and 3 (0.51 ± 0.1 mL/minute; P <0.01) than group 1 (0.33 ± 0.05 mL/minute). Periodontal parameters were worse in group 1 (P <0.05) and group 2 (P <0.05) than group 3. There was no difference in periodontal parameters, numbers of missing teeth, or salivary IL‐6 and MMP‐8 levels between patients in groups 1 and 2. Conclusion: Salivary IL‐6 and MMP‐8 levels are elevated in patients with CP with and without prediabetes.     

A 4‐ to 5‐Year Retrospective Clinical and Radiographic Study of Neoss Implants Placed with or without GBR Procedures

Background: New dental implant systems are continuously introduced to the market. It is important that clinicians report their experiences with these implants when used in different situations. Aim: The study aims to report the outcomes from a retrospective study on Neoss implants when used with or without guided bone regeneration (GBR) procedures. Materials and Methods: The study group comprised of 50 consecutive patients previously treated with 183 Neoss implants (Neoss Ltd., Harrogate, UK) in 53 sites because of single, partial, or total tooth loss. Implants were placed in healed bone in 23 sites, while a GBR procedure was used in 30 sites in conjunction with implant placement. A healing period of 3 to 6 months was utilized in 45 sites and in 8 sites a crown/bridge was fitted within a few days for immediate/early function. The number of failures, withdrawn and dropout implants was analyzed in a life‐table. All available intraoral radiographs from baseline and annual check‐ups were analyzed with regard to marginal bone level and bone loss. Results: A cumulative survival rate (CSR) of 98.2% was found for the non‐GBR group and 93.5% for the GBR group with an overall CSR of 95.0% after up to 5 years of loading. In spite of the failures, all patients received and maintained their prostheses. Based on all available radiographs, the bone level was situated 1.3 ± 0.8 mm (n = 159) below the top of the collar at baseline and 1.7 ± 0.8 mm (n = 60) after 5 years of follow‐up. Based on paired baseline and 1‐year (n = 70) and 5‐year radiographs (n = 59), the bone loss was found to be 0.4 ± 0.9 and 0.4 ± 0.9 mm, respectively. There were no statistically significant differences between GBR and non‐GBR sites with regard to implant survival or bone loss. Conclusions: The Neoss implant system showed good clinical and radiographic results after up to 5 years in function.     

Association Between Sinus Membrane Thickness and Membrane Perforation in Lateral Window Sinus Augmentation: A Retrospective Study

Background: Association between Schneiderian membrane thickness and membrane perforation is examined in lateral window sinus augmentation. Methods: This retrospective study reviewed records of 551 patients who underwent lateral sinus augmentation at Tufts University School of Dental Medicine, Boston, Massachusetts, from June 1, 2006 to May 31, 2015. Preoperative cone‐beam computed tomography images were analyzed to evaluate possible association among membrane thickness, residual bone height, and membrane perforation. Data were evaluated using Mann–Whitney U test at P <0.05. Results: Total 167 patients (95 males and 72 females) met the eligibility criteria and were included in the study. Among them, 47 patients had Schneiderian membrane perforation (perforation group). Mean membrane thickness was 0.84 ± 0.67 mm in the perforation group and 2.65 ± 4.02 mm in the non‐perforation group. There was a statistically significant difference in membrane thickness between groups (P <0.001). Mean residual ridge thickness was 2.78 ± 1.37 mm in the perforation group and 4.21 ± 2.09 mm in the non‐perforation group. There was a statistically significant difference in residual alveolar bone height (P <0.001). Conclusions: Patients who experienced membrane perforation had a thinner membrane compared with patients without membrane perforation. Schneiderian membrane perforation was associated with decreased residual bone height.     

Impact of the outcome of guided bone regeneration in dehiscence-type defects on the long-term stability of peri-implant health: clinical observations at 4 years

Objectives: To investigate the impact of residual defect height (RDH) following guided bone regeneration (GBR) in dehiscence‐type defects on the long‐term stability of peri‐implant health after a period of 4 years. Material and methods: The RDH values in dehiscence‐type defects at titanium implants were clinically assessed after 4 months of submerged healing following augmentation using a natural bone mineral (NBM) and a randomized application of either a cross‐linked‐ (VN) or a native collagen membrane (BG) (n=12 patients each). The RDH values were classified as absent (0 mm, control; n=8), minimal (1 mm, test 1; n=8), or advanced (>1 mm, test 2; n=8). Clinical parameters (i.e. bleeding on probing [BOP], probing pocket depth [PD], mucosal recession [MR]) were recorded (mesio‐, mid‐, and disto‐buccal aspects) at 4 years after prosthesis installation. Results: The mean PD (2.9±0.7, 2.8±0.7, 2.7±0.8 mm) values at 4 years were comparable in all the groups investigated. The mean MR values tended to be increased in both the test groups (0.5±0.7, 0.4±0.6 mm, respectively), when compared with the control group (0.2±0.3 mm) (P>0.05, respectively). The mean BOP values were also increased in both the test groups (45.8±30.5%, 54.1±24.8%, respectively), even reaching statistical significance when comparing test 2 and control (29.1±21.3%) groups (P=0.02). Conclusion: The present study indicated that (i) implants exhibiting RDH values >1 mm are at a higher risk of developing peri‐implant disease and (ii) positive RDH values may be associated with an increase in MR and may therefore compromise the overall esthetic outcome of implant therapy. To cite this article:
Schwarz F, Sahm N, Becker J. Impact of the outcome of guided bone regeneration in dehiscence‐type defects on the long‐term stability of peri‐implant health: clinical observations at 4 years. Clin. Oral Impl. Res 23 , 2012; 191–196.
doi: 10.1111/j.1600‐0501.2011.02214.x     

Effects of Local Melatonin Application on Implant Osseointegration

Purpose: The aim of this study was to assess the effect of local melatonin administration on bone osseointegration around implants in rabbit tibiae. Material and Methods: Ten female, 6‐month‐old New Zealand rabbits were randomly divided into two groups: the experimental group, where five rabbits were treated with local application of melatonin (3 mg) to implant sites when placed into the rabbit tibia, and the control group, those who where without additive materials. Four weeks later, animals were sacrificed; tibiae were dissected from soft tissues and fixed in buffered formaldehyde, and then included in methacrylate. Histological sections were performed to be studied under light microscopy and analyzed morphometrically to evaluate the amount of bone to implant contact (BIC), trabecular area density, and cortical area density. One‐way analysis of variance test was used for statistical evaluation. p < .05 was considered to be significant. Results: Histological evaluation showed more trabecular reaction in the melatonin group. Morphometrical analysis showed a statistically significant increase in trabecular BIC in the melatonin group when compared with the control group (24.61% ± 2.87 vs 13.62% ± 1.44; p < .01). Cortical BIC was decreased in the melatonin group, without statistical significance (71.08 ± 3.63 vs 76.28 ± 2.57; p = 0.31). Trabecular area density was increased significantly in the melatonin group (8.68 ± 1.61 vs 4.02 ± 0.36; p < .05). Cortical area density was decreased significantly in the melatonin group (91.31 ± 1.6 vs 95.7 ± 0.5; p < .05). Conclusion: Within the limitation of this animal study, local melatonin application at the time of implant placement might induce more trabecular bone at implant contact and higher trabecular area density.     

Apical U-shape splitting technique for undercut areas of the anterior alveolar ridge: a prospective non-randomized controlled study

The aim of this study was to investigate a novel apical U-shape splitting technique for horizontal bone augmentation in undercut areas and to compare its efficacy with that of guided bone regeneration (GBR). This was a prospective non-randomized controlled clinical trial. A total of 36 patients, who presented with a labial undercut that was not able to house a normally inclined implant, underwent the new technique or GBR. Radiographic and clinical data were obtained preoperatively, immediately after surgery, and 12 months after surgery. Pairwise comparisons of changes in ridge width gain, marginal bone loss, and pink aesthetic score were performed; correlations with pristine ridge morphology were investigated. The results showed similar marginal bone loss in the two groups. The overall ridge width gains in the new technique group (2.56 ± 1.92 mm) and GBR group (0.73 ± 1.21 mm) differed significantly (P < 0.05). The pink aesthetic score was higher for the new technique group (11.75 ± 1.22) than for the GBR group (9.25 ± 1.86) (P < 0.01). The morphology of the concavity had different impacts on regeneration in the two groups. The apical U-shape splitting technique, as a safe and effective alternative to GBR, provided a significant increase in bone volume gain where labial fenestration was inevitable during implant placement.     

Enamel Matrix Derivative,Alone or Associated With a Synthetic Bone Substitute,in the Treatment of 1‐ to 2‐Wall Periodontal Defects

Background: In this study, we compare the effects of enamel matrix derivative (EMD) associated with a hydroxyapatite and β‐tricalcium phosphate (HA/β‐TCP) implant to EMD alone and to open‐flap debridement (OFD) when surgically treating 1‐ to 2‐wall intrabony defects. Methods: Thirty‐four patients, exhibiting ≥3 intraosseous defects in different quadrants, were each treated by OFD, EMD, or EMD + HA/β‐TCP in each defect. At baseline and 12 and 24 months, a complete clinical and radiographic examination was done. Pre‐therapy and post‐therapy clinical (probing depth [PD], clinical attachment level [CAL], and gingival recession [GR]) and radiographic (defect bone level [DBL] and radiographic bone gain [RBG]) parameters for the different treatments were compared. Results: After 12 and 24 months, almost all the clinical and radiographic parameters showed significant changes from baseline within each group (P <0.001). Differences in PD, CAL, and DBL scores were also seen among the three groups at the 12‐ and 24‐month visits (P <0.001). At 12 and 24 months after treatment, the EMD + HA/β‐TCP group showed significantly greater PD reduction (4.00 ± 0.42 mm; 4.25 ± 0.63 mm), CAL gain (3.47 ± 0.65 mm; 3.63 ± 0.91 mm), and RBG (3.17 ± 0.69 mm; 3.35 ± 0.80 mm) and less GR increase (0.56 ± 0.37 mm; 0.63 ± 0.42 mm) compared with the OFD and EMD groups (P <0.05). Conclusion: Our data support the hypothesis that the adjunct of an HA/β‐TCP composite implant with EMD may improve the clinical and radiographic outcomes of the surgical treatment of unfavorable intrabony defects.     

Accuracy of cone beam computed tomography in assessing peri-implant bone defect regeneration: a histologically controlled study in dogs

Objective: To assess the accuracy of cone‐beam computed tomography (CBCT) in terms of buccal bone‐wall configuration and peri‐implant bone defect regeneration after guided bone regeneration (GBR). Material and methods: Titanium implants were inserted into standardized box‐shaped defects in the mandible of 12 foxhounds. Defects of one side were augmented following the principle of GBR, while the other side was left untreated. Radiological evaluation was performed using CBCT and compared with histomorphometrical measurements of the respective site serving as a validation method. Results: Non‐augmented control sites providing a horizontal bone width (BW) of<0.5 mm revealed a significantly lower accuracy between the radiological and the histological evaluation of the buccal defect depth (1.93 ± 1.59 mm) compared with the group providing a BW of >0.5 mm (0.7 ± 0.7 mm) (P<0.05, Mann–Whitney U‐test). In GBR‐treated defects, the subgroup <0.5 mm (1.49 ± 1.29 mm) revealed a significantly higher difference between CBCT and histology compared with >0.5 mm (0.82 ± 1.07) (P>0.05, Mann–Whitney U‐test). However, a radiological discrimination between original bone, integrated and non‐integrated bone substitute material was not reliable. Additionally, it was found that a minimum buccal BW of 0.5 mm was necessary for the detection of bone in radiology. Conclusion: The evaluation of peri‐implant bone defect regeneration by means of CBCT is not accurate for sites providing a BW of <0.5 mm. Moreover, a safe assessment of the success of the GBR technique is not possible after the application of a radiopaque bone substitute material. To cite this article:
Fienitz T, Schwarz F, Ritter L, Dreiseidler T, Becker J, Rothamel D. Accuracy of cone beam computed tomography in assessing peri‐implant bone defect regeneration: a histologically controlled study in dogs.
Clin. Oral Impl. Res. 23 , 2012; 882–887.
doi: 10.1111/j.1600‐0501.2011.02232.x     

Five‐Year Results Evaluating the Effects of Platelet‐Rich Plasma on the Healing of Intrabony Defects Treated With Enamel Matrix Derivative and Natural Bone Mineral

Background: Regenerative periodontal surgery using the combination of enamel matrix derivative (EMD) and natural bone mineral (NBM) with and without addition of platelet‐rich plasma (PRP) has been shown to result in substantial clinical improvements, but the long‐term effects of this combination are unknown. Methods: The goal of this study was to evaluate the long‐term (5‐year) outcomes after regenerative surgery of deep intrabony defects with either EMD + NBM + PRP or EMD + NBM. Twenty‐four patients were included. In each patient, one intrabony defect was randomly treated with either EMD + NBM + PRP or EMD + NBM. Clinical parameters were evaluated at baseline and 1 and 5 years after treatment. The primary outcome variable was clinical attachment level (CAL). Results: The sites treated with EMD + NBM + PRP demonstrated a mean CAL change from 10.5 ± 1.6 to 6.0 ± 1.7 mm (P <0.001) at 1 year and 6.2 ± 1.5 mm (P <0.001) at 5 years. EMD + NBM–treated defects showed a mean CAL change from 10.6 ± 1.7 to 6.1 ± 1.5 mm (P <0.001) at 1 year and 6.3 ± 1.4 mm (P <0.001) at 5 years. At 1 year, a CAL gain of ≥4 mm was measured in 83% (10 of 12) of the defects treated with EMD + NBM + PRP and in 100% (all 12) of the defects treated with EMD + NBM. Compared to baseline, in both groups at 5 years, a CAL gain of ≥4 mm was measured in 75% (nine of 12 in each group) of the defects. Four sites in the EMD + PRP + NBM group lost 1 mm of the CAL gained at 1 year. In the EMD + NBM group, one defect lost 2 mm and four other defects lost 1 mm of the CAL gained at 1 year. No statistically significant differences in any of the investigated parameters were observed between the two groups. Conclusions: Within their limits, the present results indicate that: 1) the clinical outcomes obtained with both treatments can be maintained up to a period of 5 years; and 2) the use of PRP does not appear to improve the results obtained with EMD + NBM.     

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.

     

Ten‐Year Results Following Treatment of Intrabony Defects With an Enamel Matrix Protein Derivative Combined With Either a Natural Bone Mineral or a β‐Tricalcium Phosphate

Background: The purpose of the present study is to evaluate the 10‐year results following treatment of intrabony defects treated with an enamel matrix protein derivative (EMD) combined with either a natural bone mineral (NBM) or β‐tricalcium phosphate (β‐TCP). Methods: Twenty‐two patients with advanced chronic periodontitis and displaying one deep intrabony defect were randomly treated with a combination of either EMD + NBM or EMD + β‐TCP. Clinical evaluations were performed at baseline and at 1 and 10 years. The following parameters were evaluated: plaque index, bleeding on probing, probing depth, gingival recession, and clinical attachment level (CAL). The primary outcome variable was CAL. Results: The defects treated with EMD + NBM demonstrated a mean CAL change from 8.9 ± 1.5 mm to 5.3 ± 0.9 mm (P <0.001) and to 5.8 ± 1.1 mm (P <0.001) at 1 and 10 years, respectively. The sites treated with EMD + β‐TCP showed a mean CAL change from 9.1 ± 1.6 mm to 5.4 ± 1.1 mm (P <0.001) at 1 year and 6.1 ± 1.4 mm (P <0.001) at 10 years. At 10 years two defects in the EMD + NBM group had lost 2 mm, whereas two other defects had lost 1 mm of the CAL gained at 1 year. In the EMD + β‐TCP group three defects had lost 2 mm, whereas two other defects had lost 1 mm of the CAL gained at 1 year. Compared with baseline, at 10 years, a CAL gain of ≥3 mm was measured in 64% (i.e., seven of 11) of the defects in the EMD + NBM group and in 82% (i.e., nine of 11) of the defects in the EMD + β‐TCP group. No statistically significant differences were found between the 1‐ and 10‐year values in either of the two groups. Between the treatment groups, no statistically significant differences in any of the investigated parameters were observed at 1 and 10 years. Conclusion: Within their limitations, the present findings indicate that the clinical improvements obtained with regenerative surgery using EMD + NBM or EMD + β‐TCP can be maintained over a period of 10 years.     

Clinical Outcomes Following Regenerative Therapy of Non‐Contained Intrabony Defects Using a Deproteinized Bovine Bone Mineral Combined With Either Enamel Matrix Derivative or Collagen Membrane

Background: The purpose of this study is to compare clinical outcomes in the treatment of deep non‐contained intrabony defects (i.e., with ≥70% 1‐wall component and a residual 2‐ to 3‐wall component in the most apical part) using deproteinized bovine bone mineral (DBBM) combined with either enamel matrix protein derivative (EMD) or collagen membrane (CM). Methods: Forty patients with multiple intrabony defects were enrolled. Only one non‐contained defect per patient with an intrabony depth ≥3 mm located in the interproximal area of single‐ and multirooted teeth was randomly assigned to the treatment with either EMD + DBBM (test: n = 20) or CM + DBBM (control: n = 20). At baseline and after 12 months, clinical parameters including probing depth (PD) and clinical attachment level (CAL) were recorded. The primary outcome variable was the change in CAL between baseline and 12 months. Results: At baseline, the intrabony component of the defects amounted to 6.1 ± 1.9 mm for EMD + DBBM and 6.0 ± 1.9 mm for CM + DBBM sites (P = 0.81). The mean CAL gain at sites treated with EMD + DBBM was not statistically significantly different (P = 0.82) compared with CM + DBBM (3.8 ± 1.5 versus 3.7 ± 1.2 mm). No statistically significant difference (P = 0.62) was observed comparing the frequency of CAL gain ≥4 mm between EMD + DBBM (60%) and CM + DBBM (50%) or comparing the frequency of residual PD ≥6 mm between EMD + DBBM (5%) and CM + DBBM (15%) (P = 0.21). Conclusion: Within the limitations of the present study, regenerative therapy using either EMD + DBBM or CM + DBBM yielded comparable clinical outcomes in deep non‐contained intrabony defects after 12 months.     

Bone regeneration in dehiscence-type defects at non-submerged and submerged chemically modified (SLActive) and conventional SLA titanium implants: an immunohistochemical study in dogs

Objectives: The aim of the present study was to evaluate bone regeneration in dehiscence‐type defects at non‐submerged and submerged titanium implants with chemically modified (mod) and conventional sandblasted/acid‐etched (SLA) surfaces. Material and Methods: Standardized buccal dehiscence defects were surgically created following implant site preparation in both the upper and lower jaws of 12 beagle dogs. Both types of implants were randomly assigned to either a non‐submerged or a submerged healing procedure. After 1, 2, 4, and 8 weeks, dissected blocks were processed for histomorphometrical [e.g. new bone height (NBH), per cent linear fill (PLF), percentage of bone to implant contact (BIC‐D), area of new bone fill (BF)] and immunohistochemical analysis. Results: At 8 weeks, non‐submerged and submerged SLA implants revealed significantly lower mean NBH (1.1±0.8–1.9±1.2 mm), PLF (27.7±20.3–46.0±28.5%), BIC‐D (26.8±10.4–46.2±16.2%), and BF (1.3±0.9–3.4±2.8 mm²) values than respective modSLA implants [NBH (2.6±0.8–4.3±0.1 mm), PLF (64.2±19.4–107.2±4.7%), BIC‐D (67.5±18.8–82.1±14.8%), BF (2.9±1.0–6.7±1.1 mm²)]. Within modSLA groups, significantly highest BF values were observed at submerged implants. Conclusion: It was concluded that (i) modSLA titanium surfaces promoted bone regeneration in acute‐type buccal dehiscence defects and (ii) a submerged healing procedure improved the outcome of healing additionally.