International Journal of Periodontics & Restorative Dentistry, 01/2015

Various designs of dental implants representing different geometries and surface technologies are commercially available for patient treatment. However, data with regard to the biologic events that occur immediately after implant placement, regardless of the surface characteristic, are scarce. It has become a common procedure to perform immediate/early prosthetic loading rather than delayed loading. The goal of this study was to observe the early biologic events of peri-implant healing to understand the role of surface modifications in relation to the early phases of bone integration. The secondary goal was to observe the possible differences in the healing pattern at two oral implant surfaces differing in morphology and roughness (Ra), with Ra values ranging from 0.5 μm (machined surface; MS) to 1.5 μm (oxidized surface; OS). A total of 36 implants were placed in six foxhound dogs, equally divided between machined and oxidized surfaces. Three implants were positioned per hemimandible following a randomization scheme. Each animal was euthanized at a specific time point for histologic observation and histomorphometry: immediately after implant insertion and after 24 hours, 7 days, 15 days, 30 days, and 90 days. The study demonstrated an extremely low bone-implant contact (BIC) for both OS and MS implant surfaces during the first 15 days after implant placement (ranging from 12.9% to 26.9% independent of the implant surface). Increased BIC values were observed only in the 30- and 90-day specimens. The presence and the degradation of residual bone particles acted as centers for new bone formation, with osteoblasts lining osteoid tissue and subsequently woven bone independent of the implant surface characteristics. The bone-forming activity appeared strongly reduced after 30 days of healing and seemed to be complete only in the 90-day specimens, where abundant lamellar bone was evident. There is a continuing effort to develop improved titanium surfaces to achieve more rapid osseointegration and improve BIC, with the ultimate goal of applying occlusal load as early as possible. Since immediate or early implant loading is applied during and not after the first 15 days, the findings in the present study of an extremely low BIC and limited mineralized bone formation for both implant surfaces during the first 15 days after implant placement suggest that the surface roughness may not be a key factor for successful osseointegration of immediately or early loaded implants. Within the limits of this study, it can be stated that osseointegration follows a similar healing pattern with machined and oxidized implant surfaces.

This study assessed the use of orthodontic extrusion (OE) for biologic width reestablishment (BWR) and compared two protocols for BWR: periodontal flap surgery (FS) performed either before (FS + OE) or after (OE + FS) extrusion. Databases were screened up to March 2013 for studies on OE, and outcomes from 13 patients treated by OE + FS or FS + OE were assessed. The results of the literature showed that OE + fiberotomy led to a greater amount of root extrusion than OE alone. The clinical/radiographic assessment demonstrated no significant differences between groups (P > .05). Within groups, there was an improvement in the keratinized tissue (P = .034) and in probing depth (P = .025) for OE + FS.

The aim of this study was to retrospectively evaluate 75 implants inserted in vertically augmented bone at the time of or prior to implant placement after 1 to 6 years of prosthetic loading. The study included 21 patients (29 surgical sites). The vertical procedure was performed combining a titanium-reinforced expanded polytetrafluoroethylene membrane with autograft (7 sites), allograft (5 sites), or auto-xenograft (17 sites). Healing was uneventful in 24 surgical sites. Three sites showed premature exposure, and two sites presented an abscess. Two implants were lost, for a cumulative survival rate of 93.6%. Mean bone remodeling at 1, 2, 3, 4, 5, and 6 years was 0.34, 0.72, 1.04, 0.84, 0.56, and 0.61 mm, respectively. The implant success rate was higher with a simultaneous approach (82.5%) compared with a staged approach (66.8%). Implants surrounded by keratinized mucosa revealed a higher success rate (82.1%) than those without it (58.4%).

The objective of this study was to evaluate the residual dentin thickness (RDT) after different tooth preparations. Ninety mandibular anterior teeth were divided into three groups: central incisors, lateral incisors, and canines. Specimens were prepared for single-crown coverage with shoulder, slight chamfer, and knife-edge finish lines. Specimens were sectioned and divided into four subgroups according to measurement areas: (1) buccal, (2) distal, (3) lingual, and (4) mesial. The RDT was analyzed statistically by means of one-way analysis of variance and Tukey post hoc test (P = .05). Significant differences were found for shoulder but not for slight chamfer and knife-edge finish lines. The interproximal areas wound up being critical due to thin RDT, potentially interfering with the structural and biologic integrity of teeth.

A retrospective radiographic study was conducted from five private dental offices on patients requesting dental implant therapy to replace their missing teeth. All implants were placed and restored by early 2000, and patients were encouraged to continue their dental care at the same office. The records were reviewed and analyzed by the clinicians, who had more than 15 years of dental experience at the time of the initial patient treatment. A total of 74 patients with 242 implants were recalled up to 10 years (mean follow-up: 9.21 ± 1.7 years) after loading. There were five implant failures from this radiographic observation period, resulting in a 97.9% dental implant survival rate. The mean crestal bone level change on the mesial aspect was -0.36 ± 1.05 mm, while the mean crestal bone level change on the distal aspect was -0.18 ± 0.96 mm. Thus, the overall mean bone loss was -0.28 ± 0.05 mm. The dental implants, which had a sandblasted, large-grit, acidetched surface, appeared to achieve successful osseointegration in this long-term observation period, and the implant system's unique design and surface features resulted in a stable osseous crest without bone loss to the first thread.

This study presents a novel bone reconstructive technique based on guided bone regeneration for localized three-dimensional hard tissue augmentation. This two-stage technique utilized a titanium osteosynthesis plate and a collagen membrane to form a physical barrier resembling a fence that contains bone graft biomaterial composed of a combination of deproteinized bovine bone matrix and autologous bone grafted from intraoral sites. Six patients were treated. At 6 months postsurgery, an increase in bone volume of 953 mm3 was shown. Mean maximum linear augmentation in the vertical direction was 6.75 mm. Histologic analysis of the regenerated area revealed the presence of compact newly formed bone with no sign of inflammation. A total of 13 implants were placed. Peri-implant marginal bone level was 0.94 mm at implant placement and 1.30 mm after 6 months. The patients were satisfied with the procedure and no complications were observed.

Peri-implantitis is an emerging problem, and corrective therapy requires a method for decontaminating the complex surface structure of the implant body and sterilizing the surrounding tissue. The erbium:yttrium-aluminum-garnet (Er:YAG) laser has proven to effectively allow tissue to regenerate when used for peri-implantitis. The power of the Er:YAG laser is absorbed by a water molecule; therefore, its target neither rises in temperature nor carbonizes. An antibacterial remedy based on the bacteriologic diagnosis, followed by debridement and sterilization of the implant surface and peri-implant tissues by Er:YAG laser is efficacious for periimplantitis treatment. The aim of this report was to present the effectiveness of the Er:YAG laser for peri-implant bone regeneration. This case series of two patients showed that antibiotic therapy reduced the bacterial amount from the periimplantitis sites significantly and that Er:YAG laser therapy, along with the bone augmentation, enhanced bone regeneration in the peri-implant bony defects.

This randomized prospective study evaluated the clinical benefits of using a corticocancellous mixture of freeze-dried bone allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement. Twenty-four patients with atrophic ridges received lateral ridge augmentations with particulate grafts placed around tenting screws and covered with a fixed acellular dermal matrix membrane. Thirty-three standard-diameter implants were successfully placed in 21 patients after a 24-week graft healing period. Three patients experienced early postoperative infections following the grafting procedure (12.5% of sites). At reentry, the allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination group (3.09 ± 0.63 mm; P = .44). The mean graft resorption between baseline and reentry averaged 13.89%.

The purpose of this randomized, controlled, split-mouth study was to compare the behavior of the extracellular matrix membrane (EMM) with autogenous subepithelial connective tissue graft (SCTG) when used as a biologic barrier in the covering of immediate implant placement after modified edentulous ridge expansion. A total of five patients between 40 and 59 years of age (three men, two women) were selected for this study and randomly assigned to one of two groups: EMM (test) or SCTG (control). Treatments were randomly assigned at the same surgical appointment. A total of 29 screw-shaped titanium implants were inserted. Clinical examinations and prophylaxis were performed in recall sessions at 2, 4, and 16 weeks postsurgery. A soft tissue biopsy was performed at both sides 4 months postsurgery. This study indicates that both procedures were effective and predictable in barrier membrane coverage after bone expansion and immediate implant placement. The use of EMM may be a valid alternative to SCTG as a biologic barrier in bone expansion procedures. The use of EMM eliminates the need for the palatal donor site and, as such, provides a less invasive solution.

The aim of this report was to suggest an alternative approach to avoid impacted canine extraction by utilizing computer-guided implant placement for providing an implant adjacent to the impacted canine without contact to the impacted tooth. In cases when the adjacent area is available for implant placement, a computerized three-dimensional (3D) planning system can be used to place implants in a way that avoids the impacted canine. Tilted implants could be used to achieve the proper support for implant-supported fixed dentures without damaging the impacted teeth. Following careful 3D planning, a computer-derived surgical stent is used to guide the surgical placement of the implants in the proper place. Since the position of the implants is known prior to the surgical procedure, a prefabricated provisional restoration is delivered immediately at the end of the surgery. Following a waiting period of 6 months, the implant-supported definitive restoration is fabricated using the same technique and delivered to the patient, making sure that proper maintenance and oral home care hygiene are feasible. This suggested treatment modality, when suitable, could provide a relatively short treatment time, a less invasive procedure, and fewer potential complications compared to the extraction of an impacted canine, massive bone grafting, and implant placement. Also, it might be assumed that the use of the native bone, as suggested here, rather than an augmented bone could lead to better long-term results.

Implant-supported prostheses often present with mucogingival deficiencies that may cause esthetic or hygienic issues. These issues may present as limited or no keratinized tissue, irregular soft tissue contour or concavity, and gray "showthrough" of the implant abutment and root forms. An interpositional soft tissue graft substitute that generates keratinized tissue and increases soft tissue thickness would be beneficial, as it would reduce donor site morbidity and be available in unlimited, off-the-shelf supply. Thirty patients were assessed as part of a multicenter, practice-based evaluation of the material. A xenogeneic collagen matrix was placed as an interpositional graft on the buccal aspect of implant sites; sites were reassessed at 6 months posttreatment. Results indicated that the collagen matrix increased tissue thickness and keratinized tissue around existing dental implants.

Leukocyte- and platelet-rich fibrin (L-PRF) belongs to a new generation of platelet concentrates. There are limited numbers of studies focused on the use of L-PRF in gingival recession defects. This study evaluated the safety and effectiveness of using L-PRF membranes as a substitute for free connective tissue grafts (CTGs) as a treatment method for gingival recession defects. A total of 44 Miller Class I/II gingival recessions that were bilateral, adjacent, and greater than 3 mm in size were selected. Each recession site was randomly assigned to the test group (L-PRF) or the control group (CTG). After 12 months, root coverage was 76.63% and 77.36% in the L-PRF and CTG groups, respectively. It is suggested that L-PRF membrane may be an alternative graft material for treating multiple adjacent recessions greater than 3 mm in size without a requirement for additional surgery.

The aim of this study was to evaluate the accuracy, in terms of trueness and precision, of optical dental scanners. An experimental acrylic resin cast was created and digitized using a microcomputed tomography (microCT) scanner, which served as the reference model. Five polyether impressions were made of the acrylic resin cast to create five stone casts. Each dental digitizer (Imetric, Lava ST, Smart Optics, KaVo Everest) made five scans of the acrylic resin cast and one scan of every stone cast. The scans were superimposed and compared using metrology software. Deviations were calculated between the datasets obtained from the dental digitizers and the microCT scanner (= trueness) and between datasets from the same dental digitizer (= precision). With exception of the Smart Optics scanner, there were no significant differences in trueness for the acrylic resin cast. For the stone casts, however, the Lava ST performed better than Imetric, which did better than the KaVo scanner. The Smart Optics scanner demonstrated the highest deviation. All digitizers demonstrated a significantly higher trueness for the acrylic resin cast compared to the plaster cast, except the Lava ST. The Lava ST was significantly more precise compared to the other scanners. Imetric and Smart Optics also demonstrated a higher level of precision compared to the KaVo scanner. All digitizers demonstrated some degree of error. Stone cast copies are less accurate because of difficulties with scanning the rougher surface or dimensional deformations caused during the production process. For complex, large-span reconstructions, a highly accurate scanner should be selected.

The purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone by means of direct clinical measuring and biopsy specimens of alveolar ridges augmented by autogenous cortical bone or titanium micromesh-both filled with autogenous particulate bone graft in the anterior jaws. For the preliminary study, 10 alveolar bone defects in five partially edentulous patients (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94) were selected. Bone defects were randomly (coin toss) divided into two groups: A (micromesh) and B (bone block). The donor site was the mandibular symphysis in all cases. On the return appointment, operative grafts appeared well incorporated into the native bone, which suggests that good contact and fit between the graft and the recipient site had been obtained during the first surgery. Histologic investigations confirmed excellent integration and revascularization of the graft in both study groups, with formation of new bone tissue without any relevant inflammation.

The aim of this study was to determine the efficacy of the lateral advanced flap in root-coverage procedures for mandibular incisors and to evaluate pain after treatment. A total of 15 patients who required treatment for gingival recessions were selected from the University of Genoa Laser and Restorative Dentistry Department. The inclusion criteria were the presence of at least one 3-mm gingival recession defect of a mandibular incisor and 3 mm or more of keratinized tissue width on the immediately adjacent tooth. One calibrated masked examiner performed the clinical measurements, including recession depth and width, probing depth, clinical attachment level, and keratinized tissue width. Patients were checked 7, 14, and 30 days after surgery and were included in supportive periodontal maintenance every 4 months. Further follow-ups were done at the first, third, and fifth year postsurgery when the same baseline assessment parameters were recorded according to the root-coverage esthetic score (RES). Numeric score recorded pain evaluations showed a mean of 3 at the day of the surgery, 2 in the first day after the surgery, and no significant scores were referred in the following days. Mean recession depth was 3.2 ± 1.3 mm at baseline; at 5 years, RES showed a positive increase of all scores. The laterally coronally advanced surgical technique was very effective in treating isolated gingival recessions. It combined the esthetic and root-coverage advantages of the coronally advanced flap with the increased gingival thickness and keratinized tissue associated with the lateral gingival flap.