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Aim: To investigate whether transmucosal healing is as effective as submerged healing in terms of buccal bone regeneration when guided bone regeneration (GBR) is performed simultaneously with implant placement., Materials and Methods: In six dogs, buccal dehiscence defects were created in the edentulous mandibular ridge, sized 5 × 5 × 3 mm (length × height × depth). In each defect, a bone-level implant was placed, and four experimental groups were randomly assigned as follows: (i) transmucosal healing with GBR (T-GBR), (ii) transmucosal healing without GBR (T-control), (iii) submerged healing with GBR (S-GBR) and (iv) submerged healing without GBR (S-control). Data analyses were based on histological slides 5 months after implant placement., Results: The T-GBR group showed significant differences compared to the control groups regarding defect height resolution, buccal bone thickness and mineralized tissue area (p < .05), but showed no significant differences when compared with the S-GBR group (p > .05)., Conclusions: The mode of healing (transmucosal vs. submerged) does not influence bone regeneration at implant sites. The clinician may therefore choose the approach based on further clinical and patient-specific parameters., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To evaluate the dimensional changes after horizontal and vertical guided bone regeneration (GBR) without membrane fixation using the retentive flap technique., Methods: This study retrospectively examined two cohorts that received vertical or horizontal ridge augmentations (VA or HA groups). GBR was performed using particulate bone substitutes and resorbable collagen membranes. The augmented sites were stabilized using the retentive flap technique without any additional membrane fixation. The augmented tissue dimensions were assessed using cone-beam computed tomography at preoperative, immediately postoperative (IP), 4 months (4M), and 1 year (1Y)., Results: Postoperative vertical bone gain in 11 participants of VA group amounted to 5.96 ± 1.88 mm at IP, which decreased to 5.53 ± 1.62 at 4M and to 5.26 ± 1.52 mm at 1Y (intragroup p < 0.05). The horizontal bone gain at IP in 12 participants amounted to 3.98 ± 2.06 mm, which decreased to 3.02 ± 2.06 at 4M and to 2.48 ± 2.09 mm at 1Y (intragroup p < 0.05). The mean implant dehiscence defect height after 1Y was 0.19 ± 0.50 mm in the VA group, and 0.57 ± 0.93 mm in the HA group., Conclusion: GBR without membrane fixation using the retentive flap technique seems to preserve the radiographic bone dimensions of vertically augmented sites. This technique may be less effective at preserving the width of the augmented tissue., (© 2023 Wiley Periodicals LLC.)

Background: The fixture thread depth reportedly influences the primary stability of dental implant, but its effect on the positional accuracy in immediate implant placement has not been reported previously., Materials and Methods: Fifty-six single-rooted, anterior and premolar teeth were extracted from six human cadavers, followed by installing either regular-threaded implants (RT group, N = 30) or deep-threaded implants (DT group, N = 26) completely relying on the surgical guide. Optical impressions taken after osteotomy and fixture installation were superimposed with the preoperative virtual planning data to measure the vertical, angular, platform and apex deviations that occurred during osteotomy and installation., Results: While the osteotomy deviations were similar between the two groups, the angular and apex deviation of the DT group (2.67 ± 2.56°; 1.04 ± 0.49 mm, respectively) were significantly larger than those of the RT group (1.61 ± 1.04°; 0.67 ± 0.41 mm, respectively) during installation (p < .05). When the installation deviations were analysed in the anterior and premolar areas separately, the angular, platform and apex deviations of the DT group (3.05 ± 3.26°; 0.75 ± 0.32 mm; 1.08 ± 0.56 mm, respectively) were significantly larger than those of the RT group (1.56 ± 0.73°, 0.59 ± 0.28 mm; 0.62 ± 0.38 mm, respectively) in the anterior site (p < .05), whereas there was no significant intergroup difference in the premolar site., Conclusion: In immediate-implant surgery, using an implant with a deeper thread might increase the deviations during installation, especially in the anterior area., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To determine the positional accuracy of implants placed with a three-dimensionally printed template having nonmetal sleeves and to determine the contributing factors to observed deviations., Materials and Methods: One hundred and eighty-seven implants placed in 72 patients were analyzed. Presurgical intraoral scans and cone-beam computed tomography images obtained before and after surgery were superimposed, and vertical, angular, platform, and apex deviations were measured between the virtually planned and actually placed positions. A multiple linear regression model was designed for identifying the contributing factors. Statistical significance was set at p < .05, with Bonferroni correction if necessary (p < .0167)., Results: A total of 187 implants demonstrated deviations of 0.65 [0.56, 0.75] mm (mean [95% confidence interval]) vertically, 3.59° [3.30°, 3.89°] angularly, 1.16 [1.04, 1.28] mm at platform, and 1.50 [1.36, 1.65] mm at apex. Implants placed in the mandible showed larger angular, platform, and apex deviations compared with those in the maxilla (p = .049, p = .014 and p = .003, respectively). Implants placed at the third or fourth nearest sites from the most-distal tooth had larger deviations than those placed at the first or second nearest sites, in vertical, platform, and apical aspects (p = .015, p = .011 andp = .018, respectively). This was only applicable to free-ending-supported templates (p < .0167), and anchor pin-supported free-ending templates (p < .0167)., Conclusion: Using a three-dimensionally printed surgical template with a nonmetal sleeve in the partial edentulous ridge resulted in larger deviations in implants placed in the mandible or distal free-end third or fourth nearest site., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri-implant bone regeneration as traditional guided bone regeneration procedures., Material and Methods: In 12 beagle dogs, implant placement and peri-implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box-shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA/TCP mixed with a synthetic PEG hydrogel, ii)HA/TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA/TCP covered with a native collagen membrane (CM), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro-CT and histological analyses were performed., Results: Histomorphometric analysis revealed a greater relative augmented area for groups with bone augmentation (43.3%-53.9% at 8 weeks, 31.2%-42.8% at 16 weeks) compared to empty controls (22.9% at 8 weeks, 1.1% at 16 weeks). The median amount of newly formed bone was greatest in group CM at both time-points. Regarding the first bone-to-implant contact, CM was statistically significantly superior to all other groups at 8 weeks., Conclusions: Bone can partially be regenerated at peri-implant buccal dehiscence defects using traditional guided bone regeneration techniques. The use of a PEG hydrogel applied as a matrix mixed with a synthetic bone substitute material might lack a sufficient stability over time for this kind of defect., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The objective of this experiment was to test whether or not a synthetic bone substitute (SBS) was more effective than a polyethylene glycol hydrogel as a carrier material for bone morphogenetic protein-2 (BMP-2) when attempting to regenerate bone., Material and Methods: Two identical, box-type dehiscence defects (4 × 4 mm buccolingually and apicocoronally, and 8 mm mesiodistally) were surgically prepared on buccal sides of the left and right edentulous ridge in five beagle dogs. Following implant placement, the defects either received (i) no graft, (ii) SBS+hydrogel, (iii) SBS+BMP-2 loaded hydrogel, and (iv) BMP-2-loaded SBS+hydrogel. The animals were euthanized at 8 weeks postsurgery. Radiographic and histomorphometric analyses were performed., Results: The hydrogel alone was not able to stabilize the grafted bone particles at 8 weeks, and SBS+hydrogel group did not significantly differ from the control group in all volumetric measurements. On the other hand, extensively regenerated new bone was connected with most of the remaining SBS particles in the BMP-2 groups. The BMP-2 groups exhibited significantly greater new bone formation (10.65 mm(3) and 1.47 mm(2) in the SBS+BMP-2-loaded hydrogel group; 14.17 mm(3) and 0.93 mm(2) in the BMP-2-loaded SBS+hydrogel) than non-BMP-2 groups (1.27 mm(3) and 0.00 mm(2) in the control group; 2.01 mm(3) and 0.19 mm(2) in the SBS+hydrogel group) in volumetric and histomorphometric analyses (P < 0.001). However, there were no significant differences between both BMP-2 groups., Conclusion: BMP-2 could yield enhanced bone regeneration in the critical-size peri-implant defects regardless of whether SBS or hydrogel is used for preloading, although the outcomes seem to be more reproducible with BMP-2 preloaded on SBS., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The objectives of this study were to analyze the presence of systemic diseases, associated complications, and other problems occurring after loading of an implanted prosthesis, and to evaluate the amount of bone resorption occurring at the apex of alveolar bone. Therefore, this study analyzed these effects on dental implants in elderly patients with systemic diseases., Study Design: In total, 35 patients over the age of 70 years who had been operated on at Seoul National University Bundang Hospital (Seongnam, Korea) between June 2003 and December 2006 were included. According to the types of additional surgical procedures, implant site, implant prosthesis, and systemic diseases, statistical comparisons were made of peri-implant bone resorption at last follow-up., Results: Following the completion of prosthodontic treatment, after a mean period of 32.7 months, the mean peri-implant bone resorption was 0.27 mm, and the peri-implant bone resorption was not significantly related to the type of upper prosthesis (P = .383), the surgical procedures accompanying placement (P = .933), or the presence/absence of systemic disease (P = .484)., Conclusions: According to this analysis, implant therapy in geriatric patients with controlled systemic disease should not be considered to be of particularly high risk., (Copyright © 2010 Mosby, Inc. All rights reserved.)

Objectives: Dental implant failures occur occasionally, and clinicians may hesitate to perform a second implantation because of the uncertain prognosis. This study was carried out to evaluate the survival rate and condition of tissue surrounding the replaced implants after removal of failed implants., Study Design: Forty-nine patients (60 implants) who underwent placement of a dental implant between June 2003 and December 2006, who experienced implant failure and underwent a second implantation at Seoul National University Bundang Hospital, were included in this study. We investigated surgery techniques in addition to the healing time after the second implantation, the type of second implantation (immediate or delayed replacement), the survival rate of the replaced dental implants, the crestal bone loss around the implant, and condition of the tissue surrounding the implant at the time of final follow-up., Results: The most frequent site of implant failure was the maxillary first molar area. The percentages of cases of immediate and delayed replacement were 48.3% and 51.7%, respectively. The average healing time for patients undergoing delayed replacement was 2.40+/-3.06 months. No significant difference in the failure rate of the second implant was observed between the immediate and delayed replacement groups (P>.05). The failure rate of the second implant after removal of failed implant was 11.7%, and a third implantation was performed for all of the failed second implantation cases. The second and third implants all survived until the final follow-up, and thus all patients had a successful implant at the time of the final follow-up. The marginal bone loss at the final follow-up (22.00+/-14.56 months after implantation) was 0.33+/-0.49 mm, the width of attached gingiva was 1.68+/-2.11 mm, the plaque index was 0.81+/-1.05, the gingival index was 0.56+/-0.63, and the pocket depth was 3.33+/-1.21 mm., Conclusions: Implant failure occurred most frequently in the maxillary first molar area. We can improve the survival rate of replaced dental implants after removing the initial failed implant using various bone grafting techniques and/or additional implant fixture., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Objectives: To evaluate clinical, clinician‐ and patient‐reported outcomes (PROs) of two adjacent single posterior implants immediately loaded with definitive single crowns up to 1 year. Ten patients in need of two adjacent posterior single implants were included. All implants were placed applying a fully digital workflow. Definitive screw‐retained single zirconia crowns were delivered within 72 h after implant placement. Clinical parameters, patient‐ and clinician‐reported outcomes were assessed up to 1 year of follow‐up. Clinical Considerations: Clinical outcomes remained stable, with no implant failures or technical and biological complications throughout the observation period. Patient satisfaction was very high at baseline (crown delivery) and remained consistently high at 6 and 12 months of follow‐up. Crown insertion 3 days after implant placement was rated as an easy procedure by clinicians. Conclusions: Two adjacent single implants with immediate definitive restorations (<72 h) in the posterior region appear to be a viable and easy treatment option to shorten the overall treatment time and potentially enhancing patient satisfaction. However, randomized controlled trials are needed to confirm the advantages of this treatment protocol over a delayed loading approach. Clinical Significance: In selected cases, immediate implant loading with definitive restorations in the posterior region appears a valuable and straightforward option to shorten the overall treatment time. [ABSTRACT FROM AUTHOR]

Objective Materials and Methods Results Conclusion To compare fully guided flapless implant surgery using a light‐cured surgical guide (FG group) with partially guided open flap surgery (PG group) in the posterior maxilla when performing simultaneous sinus floor elevation in terms of the accuracy, time requirements, and patient/clinician‐reported outcomes (PROMs and CROMs).In this study, 56 tissue‐level implants were placed with crestal sinus floor elevation in 56 patients at single‐tooth sites, with 28 implants allocated to the PG group and 28 to the FG group. The deviations of the placed implants from the virtually planned positions were measured at the implant platform and apex and for the angular deviation. The presurgical preparation time and the duration of surgery were measured. PROMs and CROMs were made by administering questionnaires at multiple time points.Horizontal deviations at the platform and apex and the angular deviation were significantly smaller in the FG group than the PG group (p < .05). Presurgical preparation and surgery times were significantly shorter in the FG group (p < .001). Patient satisfaction and willingness to receive repeat treatment were significantly better in the FG group than in the PG group (p < .005 and .025, respectively). Clinicians were more satisfied in the FG group than the PG group (p < .05).When placing an implant with sinus floor elevation, the flapless approach using a fully guided surgical system can be more accurate, faster, and increase the satisfaction of both the clinician and patient compared to the partially guided surgery. [ABSTRACT FROM AUTHOR]

Objective Materials and Methods Results Conclusion To investigate the early impact of plaque accumulation in a buccal dehiscence defect on peri‐implant marginal bone resorption.In six male Mongrel dogs, four dental implants were placed in the posterior maxilla on both sides (two implants per side). Based on the group allocation, each implant was randomly assigned to one of the following four groups to decide whether buccal dehiscence defect was prepared and whether silk ligation was applied at 8 weeks post‐implant placement for peri‐implantitis induction: UC (no defect without ligation); UD (defect without ligation); LC (no defect with ligation); and LD (defect with ligation) groups. Eight weeks after disease induction, the outcomes from radiographic and histologic analyses were statistically analyzed (p < .05).Based on radiographs, the exposed area of implant threads was smallest in group UC (p < .0083). Based on histology, both the distances from the implant platform to the first bone‐to‐implant contact point and to the bone crest were significantly longer in the LD group (p < .0083). In the UD group, some spontaneous bone fill occurred from the base of the defect at 8 weeks after implant placement. The apical extension of inflammatory cell infiltrate was significantly more prominent in the LD and LC groups compared to the UC group (p < .0083).Plaque accumulated on the exposed implant surface had a negative impact on maintaining the peri‐implant marginal bone level, especially when there was a dehiscence defect around the implant. [ABSTRACT FROM AUTHOR]

Aim: To test whether early implant placement into the extraction socket containing an uncalcified provisional matrix leads to successful osseointegration and stable marginal bone levels. Materials and Methods: In six mongrel dogs, the mandibular molars were extracted. Three weeks later, early implant placement was performed according to three experimental protocols: (i) flapless implant placement with preservation of the provisional matrix; (ii) flap elevation, socket debridement and implant placement; and (iii) flap elevation, socket debridement, implant placement and guided bone regeneration (GBR). One untreated extraction socket served as a control group. Data analyses were based on histologic slides 3 months after implant placement. Results: There were no differences in bone‐to‐implant contact between the three experimental groups (66.97%, 58.89% and 60.89%, respectively) (inter‐group comparison p =.42). Marginal bone levels, first bone‐to‐implant contact as well as the thickness of the connective tissue did not reveal any significant differences between the groups (p =.85,.60 and.65, respectively). Conclusions: Flapless early implant placement into posterior extraction sockets was as effective as an open flap approach in conjunction with GBR. Mineralization of the socket seems to occur irrespective of the presence of dental implants or biomaterials. [ABSTRACT FROM AUTHOR]

Aim: It has been proposed that platelet‐rich fibrin (PRF) can be used to support bone regeneration during alveolar ridge augmentation. The aim of this study was to determine whether an approach utilizing PRF provides similar performance to the established guided bone regeneration (GBR) procedure. Materials and Methods: Two‐wall defects were surgically created in beagle dogs and treated in three experimental groups: (i) a sticky bone (SB) substitute prepared using liquid PRF and deproteinized porcine bone mineral (DPBM); (ii) SB covered with solid PRF compressed into a membrane; and (iii) GBR performed using DPBM covered by a collagen membrane. Quantitative reverse‐transcription polymerase chain reaction was applied to the specimen after 1 week of healing, and microcomputed tomography (micro‐CT) and histological outcomes were analysed after 8 weeks of healing. Results: Compared with GBR, PRF resulted in a moderate increase in the expression levels of osteoblast and osteoclast markers, osteocalcin, and calcitonin receptor. Moreover, PRF modestly increased angiogenesis and the inflammation markers vascular endothelial growth factor (VEGF) and IL‐6. Micro‐CT and histological analyses confirmed the expected increased alveolar ridge area, with no significant differences between the three groups. Consistently, graft consolidation, as indicated by new bone formation at the defect site, did not differ significantly between groups. Conclusions: The present results demonstrate that PRF‐based approaches perform comparably to the established GBR procedure in terms of the consolidation of DPBM in two‐wall alveolar defects. [ABSTRACT FROM AUTHOR]

Aim: To test the effect of membrane fixation on ridge volume stability and new bone formation using guided bone regeneration. Materials and Methods: In eight beagle dogs, after bilateral extraction of the maxillary pre‐molars, a box‐shaped defect was created on each side. All defect sites were augmented with a particulate bone substitute material, covered with either one of two non‐cross‐linked collagen membranes (CM1 or CM2) with or without fixation (‐F or ‐UF). Samples were collected after 8 weeks. Histomorphometric and micro‐computed tomography analyses were performed. Results: Membrane fixation made no significant difference to the total augmented volume for both membranes (p >.05). Histological data indicated that at the ridge crest the augmented tissue width amounted to 2.4 ± 0.4 mm in the group CM1‐F and 2.4 ± 0.5 mm in the group CM1‐UF, with no significant difference between the groups. Conversely, in CM2‐F the augmented tissue width was significantly larger than in CM2‐UF (2.3 ± 0.1 vs. 1.57 ± 0.27, p <.05). Conclusions: Membrane fixation in contained defects failed to improve ridge volume stability regardless of the membrane type. However, it may enhance the width of the augmented ridge at the coronal portion depending on the type of membrane. [ABSTRACT FROM AUTHOR]