Implant Shoulder Research Articles

Comparing Small Buccal Dehiscence Defects Treated with or without Guided Bone Regeneration. A Sub-Analysis of a RCT.

to assess clinical and radiographical outcomes of single tooth posterior implants with a dehiscence defect treated with or without guided bone regeneration (GBR). In a randomized clinical trial of 59 patients, single-tooth posterior implants were placed. For the subanalysis of 16 patients with a buccal dehiscence defect (≤ 5mm), the implants were randomly assigned to GBR or spontaneous healing (SH). In 8 patients, the implants were surrounded by native bone (Native bone). A transmucosal healing approach was chosen for all sites. Patients were examined at restoration delivery (RD) and at one year (1y). Measurements included: soft tissue thickness (STT), bone tissue thickness (BTT) and buccal contour, based on cone-beam computed tomography (CBCT), optical scans, clinical parameters. All data were analyzed descriptively. The mean STT at implant shoulder (IS) showed a gain of 0.15 mm (Q1: - 0.16, Q3: 0.49) for the GBR group and 0.03 mm (Q1: -0.49, Q3: 0.13) for the SH group. The mean BBT 1 mm below IS showed a loss of 0.25 mm (Q1: -0.85, Q3: -0.09) for the GBR group and 0.04 mm (Q1: -0.14, Q3: 0.17) for the SH group. All peri-implant soft tissue parameters indicated healthy peri-implant tissues with no clinically relevant differences between the groups. Patient-reported outcomes regarding pain one day after surgery were similar among the study groups. The present sub-analysis resulted in a similar buccal contour and similar radiographic outcomes as well as peri-implant health for sites treated with or without GBR.

Comparing the modified socket-shield technique with the conventional immediate implantation technique in the anterior dentition: A 5-year retrospective clinical study.

The aim of this retrospective clinical study was to compare the 5-year radiological and clinical outcomes of patients undergoing immediate implantation with or without the modified socket-shield technique. Patients who underwent anterior tooth replacement via the modified socket-shield technique (MSST) or the conventional immediate implantation technique (CIIT) between 2016 and 2017 were included. The labial bone thickness was assessed at different measurement levels (0, 2, 4 and 6 mm apical to the implant shoulder (IS)) postoperatively (T1), 6 months postoperatively (T2) and 5 years postoperatively (T3). The pink aesthetic score (PES) was evaluated before surgery (T0) and at T2 and T3. Implant success, complications and patient satisfaction were evaluated at every visit. Thirty-six patients (18 in the MSST group) underwent follow-up for 5 years, with no cases of implant failure. Two cases of exposure were detected in the MSST group, but there were no significant effects on hard or soft tissue. Patients in the MSST group showed less and more stable bone resorption than did those in the CIIT group at any measurement level and any time. A higher PES was achieved in the MSST group. Patient satisfaction was similar in both groups. The MSST is a reliable immediate implantation method because of its ability to preserve the alveolar bone and provide superior recovery of aesthetics.

Influences of standardized clinical probing on peri-implant soft tissue seal in a situation of peri-implant mucositis: A histomorphometric study in dogs.

Clinical probing is commonly recommended to evaluate peri-implant conditions. In a situation of peri-implant mucositis or peri-implantitis, the peri-implant seal healing from the disruption of soft tissue caused by probing has not yet been studied. This study aimed to investigate soft tissue healing after standardized clinical probing around osseointegrated implants with peri-implant mucositis in a dog model. Three transmucosal implants in each hemi-mandible of six dogs randomly assigned to the peri-implant healthy group or peri-implant mucositis group were probed randomly in the mesial or distal site as probing groups (PH or PM), the cross-sectional opposite sites as unprobed control groups. Histomorphometric measurements of implant shoulder (IS)-most coronal level of alveolar bone contact to the implant surface (BCI), apical termination of the junctional epithelium (aJE)-BCI, mucosal margin (MM)-BCI, and MM-aJE were performed at 1day, 1week, and 2weeks after probing. Apoptosis, proliferation, proinflammatory cytokines, and matrix metalloproteinases (MMPs) of peri-implant soft tissue were estimated by immunofluorescent analysis. In the PM group, apical migration of junctional epithelium was revealed by significantly decreased aJE-BCI from 1day to 2weeks in comparison to unprobed sites (p<0.05), while no significant differences were found in the PH group. Immunofluorescent analysis showed higher levels of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), MMP-1, and MMP-8, together with exaggerated apoptosis and proliferation of peri-implant soft tissue in the PM group. Within the limitations, standardized clinical probing might lead to apical migration of the junctional epithelium in a situation of peri-implant mucositis.

Evaluation of Accuracy in Computer Guided Versus Free Hand Immediate Implant Placement in Fresh Extraction Sockets: a Randomized Controlled Clinical Trial

Background: The aim of this study was to compare between computer guided and free hand immediate implant placement in fresh extraction sockets in terms of accuracy of implant positioning.Methods: This is a randomized controlled clinical study, which used CBCT imaging and flapless surgical technique to place implants in fresh extraction sockets. Accuracy measurements were done using BluSky®1software. A total of 22 patients were recruited according to inclusion and exclusion criteria. Results: The mean values at the implant shoulder for implants inserted using computer surgical guides and those inserted using free hand technique in the mesiodistal direction were 0.69 and 1.43mm, respectively. While in the buccolingual direction they were 0.96 and 1.34mm, respectively. At the implant apex in the mesiodistal direction, they were 1.26 and 2.35mm, respectively. While in the buccolingual direction, they were 1.64 and 1.70mm, respectively. For the angular deviation they were 1.57 and 3.18mm respectively in the mesiodistal direction. Whilein the buccolingual direction were 1.29 and 7.76mm, respectively.Conclusions: Accuracy of computer guided immediate implant insertion surpasses the freehand technique in the buccolingual direction in terms of placing Immediate Implants in fresh extraction sockets in maxillary estheticregion and thus the prosthetic aspect.

Early implant placement in ridge preserved extraction sockets: A pre-clinical in vivo study.

The aim was to analyse the outcomes of early implant placement after 6 and 12weeks of healing in ridge preserved sites in a canine model. Implants were placed in second maxillary incisors sites in 9 dogs 6weeks after grafting of the sockets with 90% deproteinized bovine bone mineral in 10% collagen matrix (DBBMC) and closure with resorbable type I/III porcine collagen matrix (PCM). The implants were randomly assigned to 6 (T6) and 12 (T12) weeks of healing. The percentage of bone-to-implant contact (%BIC), old bone, new bone and residual DBBMC was similar between T6 and T12. In relation to the implant shoulder (IS), the original bone crest (IS-ROB) was more apical on the buccal than the palatal side. The regenerated bone crest (IS-C) and IS-ROB were similar between groups. However, the distance from IS to first bone-to implant contact (IS-fBIC) was significantly less in T12 compared with T6 (p=.022; Wilcoxon signed-rank test). The bucco-palatal ridge dimensions between T6 and T12 were similar. This study confirms that implants can successfully be placed early in ridge preserved maxillary second incisor sites and are osseointegrated by 6weeks. There were significantly lower IS-fBIC values at 12weeks than at 6weeks on the buccal aspect. The original buccal bone crest underwent greater corono-apical resorption than the palatal crest. The %BIC, relative proportions of mineralized tissues and dimensions of the alveolar ridge demonstrated stability between 6 and 12weeks of healing.

The Influence of Abutment Macrodesign on Facial Peri-implant Tissue Dimensions for Guided Placed and Restored Implants at Healed Sites: 1-Year CBCT Findings from a Randomized Controlled Clinical Trial.

This study aimed to evaluate facial peri-implant tissue dimensions for implants connected to either convex or concave final abutments. Patients (n = 28) were randomly allocated to receive a single implant with an abutment of either convex (Group CX) or concave (Group CV) emergence shape. Twelve months after implant placement, CBCT scans were taken and reference points were identified: first visible bone-to-implant contact, implant shoulder (IS), bone crest (BC), and marginal mucosal level (MML). Mucosal thickness was evaluated at the level of IS (MT1), above the level of BC (MT2), and at the mid-distance of BC-MML (MT3). The mean total vertical peri-implant mucosa height was 3.26 ± 0.77 mm for Group CX and 3.70 ± 0.99 mm for Group CV (P = .23). The mean vertical peri-implant mucosa height below the bone crest was 0.62 ± 0.57 mm for Group CX and 1.26 ± 0.95 mm for Group CV (P = .04). Group CV had greater mean MT2 (4.09 ± 0.72 mm vs 3.36 ± 0.81 mm; P = .02) and MT3 (2.81 ± 0.66 mm vs 2.03 ± 0.60 mm; P = .005) compared to Group CX. Abutment macrodesign may have an effect on vertical and horizontal peri-implant tissue dimensions.

Assessment of peri-implant tissue dimensions following surgical therapy of advanced ligature-induced peri-implantitis defects

BackgroundTo evaluate peri-implant tissue dimensions following implantoplasty and/or regenerative therapy of advanced ligature-induced peri-implantitis in dogs.Material and methodsAt all defect sites (n = 6 dogs, n = 48 implants), the intrabony component was filled with a particulate bovine-derived natural bone mineral (NBM). The supracrestal component was treated by either the application of an equine bone block (EB) or implantoplasty. In a split-mouth design, NBM and EB were soak-loaded with rhBMP-2 or sterile saline. All sites were covered using a native collagen membrane and left to heal in a submerged position for 12 weeks. The horizontal mucosal thickness (hMT) and bone thickness (hBT) were measured at four reference points: (v0) at the level of implant shoulder (IS), (v1) 50% of the distance IS-bone crest (BC), (v2) at the BC, and (v3) at the most coronal extension of the bone-to-implant contact.ResultsThe general tendency indicated a gradual increase in hMT from the IS (v0) toward BC (v2), which was more pronounced at implant sites treated with the regenerative approach. The hBT values increased from v2 to v3, with the highest values at the v3 region measured for implant sites treated with adjunctive rhBMP-2. For sites treated with implantoplasty, the linear regression model demonstrated an inverse correlation between hMT and hBT, whereas a positive correlation was observed at those sites treated with the regenerative approach.ConclusionHorizontal soft and hard tissue dimensions were similar among different treatment groups.

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing.

Background: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing. Methods: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months. Results: The crestal gingiva was significantly thinner in group ARP (−1.16 mm) compared to group SH (p < 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: −0.75 mm; palatal: −0.85 mm) compared to group SH (p < 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups (p > 0.05). Conclusions: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups.

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.

Histological and micro-CT analysis of peri-implant soft and hard tissue healing on implants with different healing abutments configurations.

The aim of this study was to assess the effect of different abutment configurations on peri-implant soft and hard tissue healing. Two-piece dental implants, 3.5mm in diameter and 8mm in length, were placed in four beagle dogs. Two different transmucosal healing abutment configurations were randomly selected: one with a wide emergence profile (WE) (45° angulation with implant long axis) and the other with a narrow emergence profile (NE) (15° angulation with implant long axis). After four months of healing, the animals were sacrificed. Micro-CT scans were taken for mesio-distal analysis; subsequently, the biopsies were prepared for bucco-lingual histometric analyses. Several measurements were taken using the following reference points: marginal mucosal level (MML), apical barrier epithelium (aBE), implant shoulder (IS), marginal bone crest (BC), and first bone-to-implant contact (fBIC). In the micro-CT analysis, the distance from IS-fBIC was 1.11±0.66mm for WE and 0.12±0.21mm for NE (p=0.004). The IS-BC of WE was -0.54±0.80mm, whereas NE presented 0.76±0.48mm (p=0.002). The histometric analysis showed that both groups presented comparable dimensions of peri-implant biologic width (p>0.05). However, in the distance from IS to BC, the WE showed a mean distance of -0.66±0.78mm while NE was 0.06±0.42mm (p=0.039); the IS to fBIC was 0.89±0.68mm for WE while NE was 0.30±0.30mm (p=0.041). The design of the transmucosal component can influence the establishment of the peri-implant biologic width. The flat and wide emergence profile induced an apical displacement of the peri-implant biologic width and more bone loss.

Influence of the Buccal Bone Crest Width on Peri-Implant Hard and Soft Tissues Dimensions: A Histomorphometric Study in Humans.

To histologically evaluate hard and soft tissues adaptation at screw-shaped devices installed at recipient sites in the distal segments of the alveolar edentulous ridge prepared with a buccal bone width of 1 or 2 mm. Sixteen volunteers received 2 nonsubmerged titanium implants each; after 3 months, biopsies were obtained and processed for histology. The distances between implant shoulder (IS), top of the bony crest (C), coronal level of osseointegration (B), peri-implant mucosa (PM), and apical extension of the junctional epithelium (aJE) were measured. There were no significant statistically differences between test and control sites regarding IS-C, IS-B, PM-IS, PM-B, PM-aJE, aJE-B measurements. The horizontal bone resorption 1 mm below IS was 0.3 ± 0.3 and 1.0 ± 0.7 mm at the test and control sites, respectively. This difference was statistically significant. Similar hard and soft tissues dimensions were observed in both groups. However, a higher horizontal bone resorption was seen at the control sites. Nonsubmerged implant installation should be performed when a 1 mm buccal bony crest width is present so as to limit the horizontal bone resorption.

Three-dimensional assessment of crestal bone levels at titanium implants with different abutment microstructures and insertion depths using micro-computed tomography.

To (i) assess the impact of insertion depth and abutment microstructure on the three-dimensional crestal bone-level changes at endosseous titanium implant using μCT and computerized image processing and (ii) to correlate the findings with previously reported histology. Titanium implants (conical abutment connection) were inserted in each hemimandible of n=6 foxhounds with the implant shoulder (IS) located either in epicrestal (0mm), supracrestal (+1mm) or subcrestal (-1mm) positions and randomly (split-mouth design) connected with machined or partially micro-grooved healing abutments. At 20weeks, the tissue biopsies were processed for μCT and histological (HI) analyses. The volumetric dehiscence profile around the implants was computed as distance between the implant shoulder (IS) and the most coronal bone-to-implant contact (CBI) using MATLAB. The respective buccal and oral values were averaged, and agreement with the respective IS-CBI scores from HI was assessed using Bland-Altman plots. A median net bone gain was observed for supracrestal insertion depths at both abutment types, but lower bounds of the 75% quartile experienced net bone losses. Epicrestal and subcrestal insertion depths were linked to slight bone losses, and the buccal and oral dehiscences were smaller compared to supracrestal positioning. Bland-Altman plots yielded a moderate agreement of IS-CBI values measured with μCT and HI. The novel image processing method allowed reliable evaluations and pointed to a direct impact of insertion depths on crestal bone-level changes. Additionally, it demonstrated that HI morphometry crucially depends on the chosen cutting position.

Immediate implant placement with simultaneous guided bone regeneration in the esthetic zone: 10-year clinical and radiographic outcomes.

To associate the dimension of the facial bone wall with clinical, radiological, and patient-centered outcomes at least 10years after immediate implant placement with simultaneous guided bone regeneration in a retrospective study. Primary endpoint was the distance from the implant shoulder (IS) to the first bone-to-implant contact (IS-BIC10y ). Secondary endpoints included the facial bone thickness (BT10y ) 2, 4, and 6mm apical to the IS, and the implant position. At baseline, the horizontal defect width (HDWBL ) from the implant surface to the alveolar wall was recorded. At recall, distance from the IS to the mucosal margin (IS-MM10y ), degree of soft tissue coverage of the mesial and distal aspects of the implants (PISm10y , PISd10y ; Papilla Index), pocket probing depth (PPD10y ), and patient-centered outcomes were determined. Width of the keratinized mucosa (KM), Full-Mouth Plaque and Bleeding Score (FMPS, FMBS) were available for both time points. Of the 20 patients who underwent immediate implant placement with simultaneous guided bone regeneration and transmucosal healing, nine males and eight females with a median age of 62years (42min, 84 max) were followed up for a median period of 10.5 y (min 10.1 max 11.5). The 10-year implant survival rate was 100%. Multivariate regression analysis revealed a correlation of the IS-BIC10y , controlled for age and gender, with four parameters: HDWBL (P=0.03), KMBL -10 (P=0.02), BT10 4mm (P=0.01), and BT10 6mm (P=0.01). Within the conditions of the present study, the horizontal defect width was the main indicator for the vertical dimension of the facial bone. The facial bone dimension was further associated with a reduction in the width of the keratinized mucosa and the dimension of the buccal bone.

Rehabilitation of irradiated patients with chemically modified and conventional SLA implants: five-year follow-up.

The aim of this study is to evaluate the clinical and radiological parameters of standard SLA surface implants compared to chemically modified hydrophilic SLActive implants in irradiated patients after the initial 12-month loading period up to 5 years. Twenty patients with a mean age of 61·1 years were treated with dental implants after ablative surgery and radio-chemotherapy of oral cancer. All patients were non-smokers. The placement of 102 implants (50 SLA, 52 SLActive) was performed bilaterally according to a split-mouth design. Mean crestal bone changes were evaluated using standardised orthopantomographies and clinical parameters. Data were analysed using a Kaplan-Meier curve, Mann-Whitney U-test and two-factorial non-parametric analysis. The average observation period was 60 months. The amount of bone loss at the implant shoulder of SLA implants was mesial and distal 0·7 mm. The SLActive implants displayed a bone loss of mesial 0·6 mm as well as distal 0·7 mm after 5 years. Two SLA implants were lost before loading. One patient lost five implants due to recurrence of a tumour. The overall cumulative 12-month, 3-year and 5-year survival rate of SLA implants was 92%, 80% and 75·8% and of SLActive implants 94·2%, 78·8% and 74·4%, respectively. Eighteen implants were considered lost because the patients had died. Sandblasted acid-etched implants with or without a chemically modified surface can be used in irradiated patients with a high predictability of success. Lower implant survival rates in patients with irradiated oral cancer may be associated with systemic effects rather than peri-implantitis.

Impact of abutment microstructure and insertion depth on crestal bone changes at nonsubmerged titanium implants with platform switch.

To assess the impact of microgrooved abutments and the insertion depth on crestal bone changes at titanium implants with platform switch. A total of n = 3 titanium implants (conical abutment connection) were inserted in each hemimandible of n = 6 foxhounds with the implant shoulder (IS) located at either epicrestal, supracrestal (+1 mm), or subcrestal (-1 mm) positions and randomly (split-mouth design) connected with machined or partially microgrooved healing abutments. At 20 weeks, tissue biopsies were processed for histological (primary outcome: net bone loss - NET) analyses. Subcrestal positioning of IS tended to be associated with higher mean NET values (mm) at both machined (subcrestal [-0.72 ± 0.32] > epicrestal [-0.34 ± 0.21] > supracrestal [+0.20 ± 0.64]) and microgrooved (subcrestal [-0.48 ± 0.25] > epicrestal [-0.13 ± 0.54] > supracrestal [+0.33 ± 0.58]) abutments. However, these differences failed to reach statistical significance. The insertion depth may have a direct influence on crestal bone-level changes at both types of abutments investigated.

Bone loss after ridge expansion with or without reflection of the periosteum.

To evaluate the role of the periosteum in preserving the buccal bone after ridge splitting and expansion with simultaneous implant placement. In 12 miniature pigs, the mandibular premolars and first molars were removed together with the interdental bone septa and the buccal bone. Three months later, ridge splitting and expansion of the buccal plate was performed with simultaneous placement of two titanium implants per quadrant. Access by a mucosal flap (MF) was prepared on test sides, while a mucoperiosteal flap (MPF) with complete denudation of the buccal bone was increased on control sides. After healing periods of six and 12 weeks, the animals were sacrificed for histologic and histometric evaluation. In the MF group, all 16 implants were osseointegrated, while in the MPF group, four of 16 implants were lost. Noticeable differences of bone levels on the implant surface and of the bone crest (BC) were found between the MF and the MPF group. Buccally after 6 weeks, the median distance between the implant shoulder (IS) and the coronal-most bone on the implant (cBIC) was for the MF group -1.42 ± 0.42 mm and for the MPF group -4.80 ± 2.72 mm (P = 0.15). The median distance between the IS and the buccal BC was -1.24 ± 0.51 mm and -2.78 ± 1.98 mm (P = 0.12) for the MF and MPF group, respectively. After 12 weeks, median IS-cBIC was -2.12 ± 0.84 mm for MF and -7.19 mm for MPF, while IS-BC was -2.08 ± 0.79 mm for MF and -5.96 mm for MPF. After 6 weeks, the median buccal bone thickness for MF and MPF was 0.01 and 0 mm (P < 0.001) at IS, 1.48 ± 0.97 mm and 0 ± 0.77 mm (P = 0.07) at 2 mm apical to IS, and 2.12 ± 1.19 mm and 1.72 ± 01.50 mm (P = 0.86) at 4 mm apical to IS, respectively. After 12 weeks, buccal bone thickness in the MF group was 0 mm at IS, 0.21 mm at 2 mm apical to IS, and 2.56 mm at 4 mm apical to IS, whereas complete loss of buccal bone was measured from IS to 4 mm apical to IS for the MPF group. In this ridge expansion model in miniature pigs, buccal bone volume was significantly better preserved when the periosteum remained attached to the bone.

Peri‐implant soft tissue and marginal bone adaptation on implant with non‐matching healing abutments: micro‐CT analysis

To assess (i) the outcome of changing the horizontal-offset dimension on the peri-implant soft tissues and the crestal bone and (ii) the effect of different healing abutments (flared vs. straight) on the marginal peri-implant soft tissues and crestal bone. Two-piece dental implants diameters of 3.5 and 4.5 mm were placed at least 1 mm subcrestal in five beagle dogs. Three different investigational groups: (i) 3.5-mm-diameter implant with narrow healing abutment (3.5N), (ii) 4.5-mm-diameter implant with narrow healing abutment (4.5N), and (iii) 3.5-mm-diameter implant with wide healing abutment (3.5W), were assessed. After 4 months of healing, the vertical distance from the marginal crestal bone (MB) to the implant shoulder (IS); the vertical distance from the IS to the first bone-to-implant contact; and the horizontal distance of bone ingrowth on the implant platform were measured with a high-resolution micro-CT (Xradia MicroXCT-200 system). Implants with a narrow healing caps showed an interproximal MB located between 0 and 1 mm above the implant shoulder, while the 3.5W group exhibits a mean value -0.50 mm. As all implants in group 3.5N presented a fBIC located at the level of the IS. For the 4.5N group, the mean fBIC-IS distance was -0.52 mm apically to the IS. For the 3.5WC group, the mean fBIC-IS distance was -1.42 mm. Horizontal bone apposition was only observed for the 3.5N group and the 4.5N group. The dimension of the horizontal offset would play a minimal role in reducing bone remodeling, whereas the configuration of the transmucosal component would directly influence marginal bone remodeling.

Effects of a New Implant Abutment Design on Peri-Implant Soft Tissues

The purpose of this study was to assess the effects of a modified implant abutment design on peri-implant soft and hard tissues in dogs. Three months after extraction of mandibular premolar teeth, 3 dental implants were placed in each side of the jaw using a 1-stage approach. Implants on one side of the mandible received standard abutments (control), and implants on the contralateral side received modified, patented, grooved abutments (test). Two months after implant placement, animals were euthanized and specimens were prepared for histologic and histomorphometric assessment. The linear distance (in micrometers) was measured from the implant shoulder (IS) to the following landmarks: gingival margin (GM; distance IS-GM), most apical position of the junctional epithelium (JE; distance IS-JE), and bone crest (BC; distance IS-BC). Percent of bone-to-implant contact was also measured. Histologic assessment revealed that all implants were osseointegrated and that interimplant gingival fibers between test abutments appeared to be more numerous and organized than control abutments. The IS-GM and IS-JE distances in test implants were greater than the corresponding distances in control implants (P = .024 and P = .015, respectively), whereas crestal bone loss (IS-BC) was greater for control implants than test implants (P = .037). There were no differences between control and test implants in bone-to-implant contact (P = .69), which averaged close to 50%. These results suggest that the modified groove design incorporated in standard abutments confers both soft and hard tissue benefits.

Treatment of soft tissue recessions at titanium implants using a resorbable collagen matrix: a pilot study

To histologically assess the effectiveness of a porcine-derived collagen matrix (CM) and a subepithelial connective tissue graft (CTG) for the coverage of single mucosal recessions at osseointegrated dental implants. Chronic-type mucosal Miller Class I-like recessions (mean clinical defect height: 0.67±0.33-1.16±0.19mm) were established at the buccal aspect of titanium implants with platform switch in six beagle dogs. The defects were randomly allocated to either (1) coronally advanced flap surgery (CAF)+CM, (2) CAF+CTG or (3) CAF alone. At 12weeks, histomorphometrical measurements were made (e.g.) between the implant shoulder (IS) and the mucosal margin (PM) and IS and the outer contour of the adjacent soft tissue (mucosal thickness [MT]). All treatment procedures investigated were associated with an almost complete soft tissue coverage of the defect area (i.e. coronal positioning of PM relative to IS). Mean IS-PM and MT values tended to be increased in both CAF+CM (1.04±0.74mm/0.71±0.55mm) and CAF+CTG (0.88±1.23mm/0.62±0.66mm) groups when compared with CAF (0.16±0.28mm/0.34±0.23mm) alone. These differences, however, did not reach statistical significance. Within the limits of this pilot study, it was concluded that all treatment procedures investigated were effective in covering soft tissue recessions at titanium implants.

Impact of abutment material and dis‐/re‐connection on soft and hard tissue changes at implants with platform‐switching

To assess the impact of abutment material and dis-/re-connection on soft and hard tissue changes at implants with platform-switching. Titanium implants (n = 12), placed epicrestally in the upper jaws of three dogs, were connected with titanium (Ti) and zirconium dioxide (ZrO(2) ) abutments (horizontal mismatch of 0.4 mm) and randomly allocated in a split-mouth design either to repeated (2x) dis-/re-connection at 4 and 6 weeks (test), respectively, or left undisturbed (control). At 8 weeks, histomorphometrical measurements were made between the mucosal margin (PM), implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE),-the most coronal level of bone in contact with the implant (CBI). Repeated abutment manipulation was associated with increased mean PM-aJE and IS-CBI values at both Ti (1.82 ± 0.37-1.99 ± 0.40 mm and 0.72 ± 0.18-1.12 ± 0.60 mm) and ZrO(2) (1.90 ± 0.28-2.67 ± 0.67 mm and 0.22 ± 0.10-2.15 ± 0.77 mm) abutments at 8 weeks. These vertical dimensions were comparable at both vestibular and oral aspects. Between group comparisons, however, failed to reveal a significant difference between test and control sites. Repeated manipulation may be associated with dimensional changes of peri-implant soft and hard tissues formed at both non-matching Ti and ZrO(2) abutments.