The goal of this investigation was to evaluate the bone-to-implant contact (BIC) of dental implants placed into fresh extraction sockets without pre-existing periapical pathology. When the extraction sites exhibited a gap distance of > 2 mm, autogenous bone harvested from surrounding surgical sites was grafted to fill that gap with no barrier membranes. All implants were clinically stable and successful at 6 months postoperative. The histologic examination demonstrated an average of 66.2% BIC for all five immediately placed dental implants. The results of this study provided sufficient histologic and histomorphometric knowledge to support immediate dental implant placement in carefully selected clinical scenarios.

The goal of this investigation was to evaluate the efficacy of dental implants with a surface that was sandblasted with large grit and acid etched in a human model. Seven patients volunteered to allow the biopsy of a small implant in exchange for complete dental rehabilitation at no cost. All biopsy sites received soft and hard tissue reconstruction, and this report provides observation of successful bone-to-implant contact and successful prosthesis construction for the patient. The patients enthusiastically reported improved quality of life as a result of participation in this study. The surgeons’ confidence in this implant was reflected by the clinical and histologic result of the study.

Background and aims: There are some studies comparing bone replacement grafts. The aim of this study was clinical evaluation of the effect of Osteon® (as a new bone material) and Bio-Oss® (Bovine-derived hydroxyapatite) in the treatment of mandibular molar class II furcation defects in humans.

Materials and methods: Eleven patients (10 females and 1 male, age range of 27-59 years ; mean age of 45.5±11.8 years) who had at least 22 mandibular class II buccal or lingual furcation defects were treated either with Osteon (as the case group) or Bio-Oss (as the control group). Each defect was randomly assigned to either the case group or the control group. Clinical parameters and the soft tissue and hard tissue measurements, including plaque index (PI), gingival index (GI), gingival recession of furcation area (GR), pocket depth (PD), clinical attachment level (CAL), horizontal defect depth (HDD), vertical defect depth (VDD) were recorded at baseline and six months after surgery. Data were analyzed using t-test or Wilcoxon's test.

Results: Similar healing results were observed for both treatments. The results showed significant probing depth reduction (case group: 0.77 mm and control group: 0.84 mm) and HDD reduction (case group: 0.51 mm and control group: 0.8 mm) and PI reduction. There was not statistically significant difference between the groups in all soft and hard tissue parameters.

Conclusion: The results of this study showed that the effect of using Osteon as a bone graft material is the same as that of Bio-Oss in the treatment of mandibular class II furcation defects.

Background: Many studies have shown favorable results following the use of different bone graft materials. The aim of the present study was to evaluate the biocompatibility of four different bone graft materials regarding cell viability and morphology of Human osteoblast-like cells (SaOS-2) in vitro.

Materials and methods: The effects of Bio-Oss(®), Tutodent(®), Osteon(®), and Cerasorb(®) were studied on the human osteoblast-like cell line to evaluate various parameters. Human osteoblast-like cells were seeded onto the mentioned bone substitute materials (BSMs). Cell differentiation; cell viability and alkaline phosphatase (ALP) activity of the seeded cells were evaluated by means of scanning electron microscopy, cell viability test and phase contrast microscopy Analysis of variance (ANOVA). Tamhane's post-hoc, Kruskal-Wallis Test, and Dunn's Test were used. The results were considered to be statistically significant at P<0.05.

Results: The control group (SaOS-2 cells which were incubated in Dulbecco Modified Eagle Medium without any kind of bone graft materials) had the highest level of cell viability (P<0.001), followed by Tutodent(®), Osteon(®), Cerasorb(®), and Bio-Oss(®). There was no significant difference in MTT assay results between Tutodent(®) and the control group (P=0.032). All tested bone graft materials showed significantly higher ALP activity than the control (P<0.001). The Tutodent(®) group showed the best cell growth among all experimental groups, followed by the Osteon(®) group. The former had a higher spindle-like morphology with good attachment to the surface. Cells cultivated on the surfaces of the Cerasorb(®) and Bio-Oss(®) granules had more round morphologies.

Conclusion: This in vitro study demonstrated that all tested BSMs can provide good cell differentiation but a lower rate of proliferation.

Purpose: The aim of this study was to evaluate and compare the clinical and radiographic outcomes of single implants with a platform-switched rough collar (PSRC) and a platform-matched smooth collar (PMSC).

Materials and methods: Twenty-six patients missing a tooth in the anterior maxilla (through the premolars) were randomly assigned to the PSRC or the PMSC group. All implants were placed in a flapless approach and restored with an early loading protocol. Clinical measurements were performed at surgery, loading, and at 3, 6, and 12 months after loading. In addition, radiographic evaluations were carried out using standardized periapical radiographs and cone beam computed tomography. Patient satisfaction surveys were completed, and microbial analysis with DNA probes was performed.

Results: The implant survival rate was 100% for both groups. The mean marginal bone level (MBL) was significantly higher in the PSRC group compared to the PMSC group at all time points. From the 2-week postoperative visit to 1 year postloading, the mean MBL change in the PSRC group was 0.21 ± 0.56 mm and in the PMSC group it was 0.74 ± 0.47 mm. Soft tissue profiles were stable over time, with no significant differences between groups. There were no significant differences between groups in the number of microbial species seen. Patients in both groups were highly satisfied with postoperative and postprosthetic experiences.

Conclusion: In this study, the PSRC method preserved marginal bone by a mean of 0.53 mm more than the standard PMSC protocol. Within the limitations of the present study, it can be concluded that the PSRC protocol may be beneficial in marginal bone preservation. Longitudinal studies are needed to verify the long-term effects of this approach.

Objectives: The purpose of this investigation was to evaluate the effects of different implant surface treatments on implant stability in dog mandibles.

Material and methods: A total of 30 implants (Dentium Co, Seoul, Korea) were placed in 5 dog mandibles. Bone quality was assessed at each site. Implant stability was evaluated using 2 different methods. An Osstell resonance frequency analyzer (RFA) was used to determine the stability at baseline (day 1), and 3, 6 and 10 weeks after surgery. Animals were euthanized 10 weeks after implant installation. Specimens were obtained and submitted to the laboratory processing. Sections were stained with hematoxylin and eosin for histologic and histomorphometric analyses. All implantation sites in dog mandibles demonstrated bone types II and III.

Results and conclusions: All implants showed good primary stability at baseline in terms of insertion torque. The results of this study suggest that surface treatment may have significant effects on biological stability 3 weeks after implant placement. Further studies are needed to confirm these initial observations in poor quality bone.

Purpose: Less morbidity is the major advantage to a one-stage crestal approach to maxillary sinus elevation. However, the ability to ensure high primary implant stability in a severely atrophied ridge is of chief concern. The purpose of this study is to measure and compare the success rate of implants placed at the time of crestal approach sinus lift in patients with ≤ 4 mm of residual alveolar bone (RAB) and >4 mm of RAB.

Materials and methods: In this three-site multicenter study, one hundred two patients, 53 males and 49 females, (23-89 years old; mean = 56.2) were evaluated. Three experienced surgeons (>15 years) performed the crestal approach sinus lift microsurgeries with simultaneous implant placement. At baseline and at the follow-up appointments, calibrated examiners measured radiographic interproximal bone level using ImageJ for Windows after calibration of the radiographs. References for the bone level measurements were the platform, first and second threads of the implants. Statistical analyses, using STATA version 12, stratified patients according to RAB height (group 1: RAB of ≤ 4 mm; n = 35 and group 2: RAB > 4 mm; n = 67), age, gender, and treatment center.

Results: The success rate was 100% for group 1 and 98.51% for group 2 at 6 to 100 months postprosthetic loading (mean = 29.7 months). The peri-implant bone loss averaged 0.55 mm (interquartile range [IQR] = 0.5 [0-1]) in group 1 and 0.07 mm (IQR = 0 [0-0]) in group 2. There was no statistically significant difference between the two groups. Clinical outcomes were independent of age, gender, and treatment center.

Conclusions: The RAB height did not increase crestal bone loss or reduce the success rate of the implants and associated prostheses. The crestal approach should be considered a viable technique for use in patients with residual bone height of ≤ 4 mm and merits further evaluation.

Background: Previous studies showed that the use of a porous titanium membrane (TM) for exophytic bone regeneration does not effectively inhibit the infiltration of undesired tissue. Therefore, this study examines the effect of resorbable collagen membranes, such as cross-linked type I collagen membrane (BA) and double-layered porcine collagen membrane (BG), on the promotion of exophytic bone formation in guided bone regeneration when used in conjunction with a porous TM.

Methods: Thirty-six male New Zealand white rabbits were used in this study. Six rabbits were allotted to each test group. After decorticating the parietal bone, with or without filling the inner space with a freeze-dried cortical bone allograft (OG), the collagen membranes were fixed with metal pins. The experimental groups were divided into the following six groups: TM only, TM + OG, TM + BA, TM + BG, TM + OG + BA, and TM + OG + BG. The experimental animals were sacrificed at 8 and 16 weeks after surgery. Non-decalcified specimens were prepared and processed for histologic observations. The newly formed bone (percentage) was measured histomorphometrically.

Results: BG combined with TM promoted new bone formation and maturation by inhibiting the infiltration of connective tissue. However, BA had no significant effect on new bone formation. The amount of new bone formation was higher at 16 weeks than at 8 weeks, but the difference was not significant. At 16 weeks, the best result for newly formed bone was with TM + OG + BG, with a significant difference from TM alone and TM + BA.

Conclusions: Regardless of the use of graft materials, BG combined with TM promoted more bone formation than BA combined with TM or TM alone. Thus, using a commercial collagen membrane to cover a TM can promote new exophytic bone formation.

Background: Implant therapy is a highly predictable treatment option; however, insufficient data exist to show whether flapless implant surgery provides better esthetic outcomes and less bone loss than implant surgery with a flap approach.

Methods: In this randomized, controlled study comparing the flapless and traditional flap protocol for implant placement, 24 patients received a single implant in the anterior maxillary region. A cone beam computed tomography-aided surgical guide was used for implant placement surgery for both groups. Implants were restored using a one-piece, screw-retained ceramic crown at 3 months. Radiographic and clinical measurements were assessed at baseline (implant placement) and at 3 (crown placement), 6, 9, and 15 months. Clinical parameters evaluated were plaque index, gingival index, papillary index (PPI) (0 = no papilla, 1 = less than half, 2 = more than half but not complete, 3 = complete fill, and 4 = overfill), marginal tissue levels, biotype, width of keratinized tissue, and soft tissue thickness.

Results: Implant success rate was 92% in both groups. Mean PPI values for the flap control group and flapless test group were 2.38 ± 0.51 versus 2.31 ± 0.48 at crown placement (P = 0.68) and 2.52 ± 0.52 versus 2.64 ± 0.54 at 15 months (P = 0.42), respectively. PPI increased over time in both groups, although the flapless group had a significantly larger change in PPI from crown placement to 6 and 9 months (P <0.01). Crestal bone levels in the flap group were more apical in relation to the implant platform than those in the flapless group for the duration of the study. No differences among groups were noted for all other measurements.

Conclusions: Both flapless and flap implant placement protocols resulted in high success rates. A flapless protocol may provide a better short-term esthetic result, although there appears to be no long-term advantage.

Purpose: The aim of this study was to analyze and compare the level and distribution of peri-implant bone stresses associated with mandibular two-implant overdentures with different implant positions.

Materials and methods: Mathematical models of mandibles and overdentures were designed using finite element analysis software. Two intraosseous implants and ball attachment systems were placed in the interforaminal region. The overdenture, which was supported by the two implants, was designed to withstand bilateral and unilateral vertical masticatory loads (total 100 N). In all, eight types of models, which differed according to assigned implant positions, height of attachments, and angulation, were tested: MI (model with implants positioned in the lateral incisor sites), MC (implants in canine sites), MP (implants in premolar sites), MI-Hi (greater height of attachments), MC-M (canine implants placed with mesial inclination), MC-D (canine implants placed with distal inclination), MC-B (canine implants placed with buccal inclination), and MC-L (canine implants placed with lingual inclination).

Results: Peri-implant bone stress levels associated with overdentures retained by lateral incisor implants resulted in the lowest stress levels and the highest efficiency in distributing peri-implant stress. MI-Hi showed increased stress levels and decreased efficiency in stress distribution. As the implants were inclined, stress levels increased and the efficiency of stress distribution decreased. Among the inclined models, MC-B showed the lowest stress level and best efficiency in stress distribution.

Conclusion: The lowest stress and the best stability of implants in mandibular two-implant overdentures were obtained when implants were inserted in lateral incisor areas with shorter attachments and were placed parallel to the long axes of the teeth.

Purpose: This study compared the volume stability and bone-forming capacity of biphasic calcium phosphate (BCP) with a high versus a low ratio of (β-tricalcium phosphate (β-TCP) relative to hydroxyapatite (HA), i.e., 70:30 vs 30:70, in the rabbit sinus model.

Materials and methods: Bilateral sinus windows were created in eight adult New Zealand white rabbits (2.5 to 3.5 kg); each sinus in each rabbit was assigned to one of two experimental BCP groups according to the HA: β-TCP ratio. One sinus was grafted with BCP with a high ratio of β-TCP (30:70; TCP70), and the contralateral sinus was grafted with BCP with a low ratio of β-TCP (70:30; TCP30). The animals were sacrificed after 2 weeks (n = 4) or 8 weeks (n = 4) of healing. Biopsy specimens were harvested and evaluated histologically, histomorphometrically, and with microcomputed tomography.

Results: The bone volume did not differ significantly between the two groups at each healing point, or between 2 and 8 weeks of healing in both groups. The amount of new bone increased significantly between 2 and 8 weeks of healing in both groups, and it did not differ significantly between the TCP30 and TCP70 groups. The residual material was significantly more resorbed in the TCP70 group than in the TCP30 group at both 2 and 8 weeks. In the TCP70 group, a greater number of multinucleated giant cells were observed at both weeks. The bone-to-residual material contact ratio did not differ significantly between the two groups.

Conclusion: The volume stability and osteoconductive capacity of BCP with an HA: β-TCP ratio of 30:70 was comparable to that with an HA: β-TCP ratio of 70:30. Thus, within the limitations of this study, it can be argued that BCP with an HA: β-TCP ratio of 30:70 can be successfully used for sinus augmentation.

Purpose: Primary implant stability is critical to achieving implant success, especially in a situation with immediate implant placement and provisionalization (IIPP) when bone quality and quantity are compromised. The purpose of this study was to examine the effects of implant morphology (tapered vs cylindric) and the final drill-implant diameter discrepancy (FD-IDD) of six implant systems on the incidence of rotational instability during IIPP in the esthetic zone.

Materials and methods: One hundred seventy-one implants in 112 patients were evaluated. Implants that exhibited inadequate resistance to the torque generated by the surgeon's hand during implant placement were classified as rotationally unstable.

Results: The overall incidence of rotational instability for the tapered implants (1.1%) was significantly lower than that exhibited by the cylindric (nontapered) implants (20.5%). Among the cylindric implants, those with < 0.5 mm FD-IDD experienced a significantly higher incidence of rotational instability (36.6%) than groups with ≥ 0.5 mm FD-IDD. The incidence of rotational instability of cylindric implants with ≥ 0.5 mm FD-IDD was significantly greater than that of the tapered implants with a comparable FD-IDD.

Conclusion: Within the confines of this study, the use of a tapered implant with an FD-IDD of ≥ 0.5 mm minimized the incidence of rotational implant instability for the IIPP procedure.

This paper presents the results of a prospective study on the clinical effect of grafting the buccal gap with platform switching, following flapless tooth extraction and immediate implant placement and provisional restoration, on (1) alterations in buccolingual ridge dimension and (2) midfacial peri-implant soft tissue thickness. Fifty-six patients were placed in one of four treatment groups: (1) a non-platform-switching implant (Non-PS, n = 14); (2) a non-platform-switching implant and bone graft (BG/Non-PS, n = 14); (3) a platform-switching implant (PS, n = 15); and (4) a platform-switching implant and bone graft (BG/PS, n = 13). Buccolingual ridge dimensional change and peri-implant soft tissue thickness at 2 mm below the free gingival margin were measured. Both PS and BG/PS groups showed an increase in buccolingual dimension compared to the contralateral natural tooth site as well as peri-implant soft tissue thickness of > 2.5 mm, clinically. Platform switching was associated with significantly greater midfacial soft tissue thickness than bone grafting (mean ± standard deviation: 2.17 ± 0.04 for Non-PS and 3.55 ± 0.14 for PS). Using platform-switched implants, in conjunction with immediate implant placement and immediate provisional restoration, was associated with a significantly greater stability of ridge dimension and peri-implant soft tissue thickness than using non-platform-switched implants when measured 12 months after placement of the final restoration. Platform switching may help achieve preservation of ridge dimension and enhance the stability of peri-implant soft tissue following immediate implant placement and provisional restoration without bone grafting. Further research is required to assess the long-term outcome.

The presence of adequate gingiva with firm attachment to the underlying periosteum and bone is important for the overall long-term success of implant-supported oral rehabilitation. In the presence of an atrophic edentulous mandible, peri-implant soft tissue management is a challenging task. Therefore, mucosal grafts are sometimes necessary in patients with insufficient attached gingiva around abutments. Immobilization of this graft is mandatory for its survival. The study design included 5 edentulous patients with inadequate attached gingival zone, all candidates for implant surgery and free gingival graft. In the first surgery the implants were inserted, and in the second operation a free gingival graft was obtained from the palate and sutured to the mandibular site. A newly designed stent was applied for the stabilization of the graft. Two to 3 weeks after the second surgery, the stents were removed and the attached gingival width was measured. Long-term evaluations were performed to follow the survival of the graft. All grafts were intact at the time of stent removal. In all cases, the long-term evaluations revealed adequate attached gingiva around the implant. It may be concluded that immobilization of free gingival graft in the recipient site increases its success rate and its survival rate. The application of the newly designed stent can serve as a proper and easy immobilizer for peri-implant soft tissue management.

Purpose: Maxillary sinus augmentation has been a predictable procedure. However, in-depth analysis of tissue healing after sinus grafting with simultaneous implant placement is limited. This study aimed to compare histologic outcomes after sinus grafting with a synthetic bone graft compared with a xenograft.

Materials and methods: A randomized controlled split-mouth study was conducted to compare bone formation around microimplants (2.00 mm, Dentium) placed at the time of maxillary sinus augmentation with a synthetic material (Osteon, Dentium) (OST) and deproteinized bovine bone (Bio-Oss) (BIO) as the control group. Four microimplants per subject (n = 13) were placed bilaterally for intrasubject comparison (two implants per side/patient). Bone cores with osseointegrated microimplants were harvested for histomorphometric analysis 6 to 8 months after sinus augmentation surgery.

Results: Histologic analysis revealed newly formed bone deposited on the microimplant surface and bridging to bone graft material in both groups. Further, there was no histologic evidence of signs of inflammation in all specimens. In general, bone-to-implant contact was comparable and ranged from 6.1% to 67.0% with a mean of 38.4% ± 11.61% in OST and from 10.5% to 57.0% with a mean of 34.58% ± 12.55% in BIO. However, a significantly higher percentage of bone-to-implant contact in the first four threads of the grafted area was noted in OST compared with BIO (P = .016).

Conclusion: The synthetic OST was found to be equivalent to BIO in new bone formation and clinical success after sinus augmentation in conjunction with microimplant placement. Although there are some statistically significant differences in the histologic outcomes, the clinical relevance of these needs to be further evaluated. Nevertheless, the findings of this study indicate that this synthetic alloplast would be a viable alternative to an allograft material.