Volumetric alterations around single-tooth implants using the socket-shield technique: preliminary results of a prospective case series.

OBJECTIVE: To demonstrate in a prospective cohort study that immediate implantation and provisionalization in combination with the socket-shield technique will result in volume stability of the mucosa adherent to the inserted implant. MATERIAL AND METHODS: Patients with an indication for a single tooth implant underwent application of the socket-shield technique and immediate implantation of a provisional implant crown. A noninvasive volumetric measurement was performed according to the method described by Windisch et al (2007) at baseline and 12 weeks later. The influence of potential confounders was evaluated. Patients rated their satisfaction with the treatment, fitting accuracy of implant, intraoperative discomfort, postoperative pain, and ability to chew soft and hard foods using visual analog scales. RESULTS: Fifteen patients with a mean age of 49.2 ± 11.9 years were enrolled in the study. All implant sites showed uneventful healing and no socket-shield exposures were observed. The soft tissue volume change assessed with the mean distance change was < 0.5 mm in all cases (-0.07 ± 0.16; range -0.37 to +0.32). A slight but significant influence of the buccal bone plate width on the soft tissue volume change was observed (b = 0.25; P = 0.037). No influence was found for apical bone height, width of gingival tissue, buccal recession or probing depths. The patients were highly satisfied with their treatment as well as with the pain and functional outcomes. CONCLUSIONS: Based on preliminary data, preservation of a buccal root segment in conjunction with immediate implant placement and provisionalization can minimize buccal contour changes after tooth extraction on a short-term basis.

Zygomatic implant placement in conjunction with sinus bone grafting: the "extended sinus elevation technique." a case-cohort study.

PURPOSE: The zygomatic implant is mainly indicated for the rehabilitation of extremely atrophied maxillae when bone augmentation should be avoided. One drawback of zygomatic implants, which typically pass through the sinus, is initial or late bone resorption around the implant neck, which can result in oroantral communications followed by possible infection of the sinus. To decrease the risk of sinus infection, a modified technique was developed to preserve the integrity of the sinus membrane and to regenerate bone around zygomatic implants using an extended sinus grafting approach. MATERIALS AND METHODS: Patients with extremely atrophied maxillae were provided with one to four zygomatic implants in conjunction with sinus grafting, plus conventional auxiliary implants, for immediate support of a provisional full-arch maxillary prosthesis. Definitive prostheses were delivered at 6 months after implant placement. All patients underwent clinical and radiographic examinations at 6 months. RESULTS: Twenty-two zygomatic and 23 conventional auxiliary implants were placed in 10 patients. The overall 6-month implant survival rate was 90.9% for zygomatic implants and 100% for auxiliary implants placed in the anterior area. Only two minor technical complications were seen, and clinical indicators (including probing pocket depth, keratinized tissue, and plaque and bleeding indices) were good in all patients. A substantial gain of radiographic bone around the zygomatic implants was observed. CONCLUSION: The proposed technique led to successful prosthetic function for all patients. With the described technique, exposed implant threads within the maxillary antrum are eliminated and the potential for biologic complications is minimized.

The bone lamina technique: a novel approach for lateral ridge augmentation--a case series.

The goal of this case series is to present a novel treatment approach for lateral ridge augmentation. Four systemically healthy patients (aged 48 to 59 years) with inadequate dental alveolar ridge widths were selected for inclusion. All ridge defects were augmented using a xenogeneic cortical bone shield in combination with particulated bone substitutes and a thin collagen barrier. At baseline and after 6 months, digital cone beam computed tomography scans were performed. Biopsy specimens were harvested at reentry surgery and processed for histologic analysis. The results revealed a sufficient amount of bone structure for implant placement without additional augmentation procedures. The histologic analysis demonstrated that new bone formation had taken place and the bone shield had resorbed entirely. This case series indicates that the bone lamina technique has the biologic and mechanical properties to successfully achieve hard tissue augmentation of deficient ridges.

Dimensional alterations of extraction sites after different alveolar ridge preservation techniques - a volumetric study.

OBJECTIVES: The aim of this randomized controlled clinical study was to assess soft tissue contour changes after different alveolar ridge preservation procedures. MATERIAL AND METHODS: Following tooth extraction, 30 patients were randomly assigned to the following treatments (Tx) - Tx 1: xenogenic bone substitute (pre-hydrated collagenated cortico-cancellous porcine bone) and free gingival graft; Tx 2: free gingival graft alone; Tx 3: xenogenic bone substitute; Tx 4: no further treatment (control). Impressions were obtained before tooth extraction (baseline) and 4 months after surgery. Cast models were optically scanned, digitally superimposed and horizontal measurements of the contour alterations between time points were performed using digital imaging analysis. RESULTS: All groups displayed contour shrinkage at the buccal aspect ranging from a mean horizontal reduction of -0.8 ± 0.5 mm (Tx 1) to -2.3 ± 1.1 mm (control). Statistically significant differences were found between Tx 1 and Tx 4 as well as Tx 2 and Tx 4. A significant positive influence of the free gingival graft on the maintenance of the ridge width was recorded (p < 0.001). CONCLUSION: In this study, alveolar ridge preservation techniques were not able to entirely compensate for alveolar ridge reduction. Covering the orifice of the extraction socket with a free gingival tissue graft seems to have the potential to limit but not avoid the post-operative external contour shrinkage based on optical scans.

The Healing of Free Gingival Autografts for Socket-seal Surgery: a Case Report.

Tooth extraction will be followed by marked alterations to the tissue volume, in particular in the anterior zone, which may jeopardize the esthetic outcome of any dental treatment involving tooth extraction. If, however, ridge collapse can eb prevented or minimized after tooth extraction, more predictable outcomes with superior esthetics can be accomplished along with fewer surgical procedures. Therefore, it was proposed that stabilizing the soft tissue architecture with a free gingival graft could minimize the soft tissue shrinkage. The following case report describes some surgical modifications and refinements in order to enhance the predictability of the socket-seal surgery.

Immediate loading of fixed provisional prostheses using four implants for the rehabilitation of the edentulous arch: a prospective clinical study.

PURPOSE: The purpose of this prospective clinical trial was to evaluate over a 5-year period the treatment outcomes for immediately loaded full-arch fixed prostheses supported by two axially inclined and two tilted implants used to rehabilitate edentulous arches. This report presents preliminary 1-year results. MATERIALS AND METHODS: Thirty-seven patients were recruited for treatment with either mandibular or maxillary full-arch fixed prostheses supported by four implants. Within 24 hours, the implants were immediately loaded with screw-retained full-arch acrylic resin provisional restorations. Definitive reconstructions were delivered 6 months later. Complete full-arch prostheses were supported by metal frameworks combined with high-density acrylic resin. Follow-up visits were scheduled for 6 and 12 months after initial prosthetic loading and then annually for up to 5 years. Digital radiographs were obtained immediately, 6 months after surgery, and at each annual follow-up visit. Marginal peri-implant bone levels were assessed using digital image analysis. RESULTS: The 1-year implant survival rates were 96.0% for axially positioned implants and 94.6% for tilted implants. The survival rates were 96.6% for maxillary implants and 98.7% for mandibular implants. The prosthetic survival rate was 100%. No significant differences were found in the results for tilted versus axially positioned implants. One year after loading, the mean marginal bone loss was 0.82 ± 0.31 mm around the axially oriented implants and 0.76 ± 0.49 mm around the tilted implants (P ⋜ .05). CONCLUSIONS: Preliminary data from this clinical trial show high implant survival rates for immediately loaded full-arch prostheses supported by four implants. Immediate loading of tilted implants may be considered a viable treatment option for the rehabilitation of edentulous patients.

Bone engineering-vitalisation of alloplastic and allogenic bone grafts by human osteoblast-like cells.

Human osteoblasts on non-sintered hydroxyapatite and demineralised bone matrix (DBX) were analysed in vitro to find out whether they would be suitable for reconstruction of bones in oral surgery. Human osteoblasts were isolated from the jaw during routine dental operations and seeded onto the two biomaterials. Cells were characterised by assay of alkaline phosphatase, detection of type 1 collagen, and production of osteocalcin. After 21 days of cultivation, the cell/biomaterial constructs were examined by scanning electron microscopy, thin sections, and propidium iodide/fluorescein diacetate staining. The osteoblasts formed a vital multiple cell layer on DBX within 3 weeks of cultivation. On hydroxyapatite, the cells showed no tendency to proliferate or migrate onto the synthetic biomaterial, or to form well-spread and viable cell constructs. These findings suggest that surface morphology or the presence of osteoinductive factors may have an important role in the adhesion and proliferation of osteoblasts. Human DBX can be colonised by human osteoblast-like cells in vitro, indicating the potential of allogeneic carriers for future procedures in bone engineering.

Dimensional changes of the ridge contour after socket preservation and buccal overbuilding: an animal study.

OBJECTIVES: The aim of the study was to volumetrically assess alterations of the ridge contour after socket preservation and buccal overbuilding. MATERIAL AND METHODS: In five beagle dogs, four extraction sites were subjected to one of the following treatments: Tx 1: The socket was filled with BioOss Collagen and covered with a free gingival autograft from the palate (SP). Tx 2: The buccal bone plate was forced into a buccal direction using a manual bone spreader and SP was performed. Tx 3: The buccal bone plate was forced into a buccal direction using a manual bone spreader; SP was performed. Tx 4: The socket was filled with BioOss Collagen and a combined free gingival/connective tissue graft was used to cover the socket and for buccal tissue augmentation. Impressions were obtained at baseline, 2 weeks and 4 months post-operatively. Casts were optically scanned and superimposed in one common coordinate system. Using digital image analysis, the volumetric differences per area among the different treatment time points and among the treatment groups were calculated. RESULTS: Four months after tooth extraction, no statistically significant differences with regard to the buccal volume per area could be assessed among the treatment groups. CONCLUSION: Overbuilding the buccal aspect in combination with socket preservation is not a suitable technique to compensate for the alterations after tooth extraction.

Biomechanical and histological behavior of zirconia implants: an experiment in the rat.

OBJECTIVE: This study aimed at evaluating the integration of zirconia implants in a rat femur model. MATERIAL AND METHODS: Zirconia implants with two distinct surface topographies were compared with titanium implants with similar topographies. Titanium and zirconia implants were placed into the femurs of 42 male Sprague-Dawley rats. Four groups of implants were utilized: machined zirconia implants, zirconia implants with a rough surface, machined titanium implants, and titanium implants with an electrochemically roughened surface. After a healing period of 28 days, the load-bearing capacity between the bone and the implant surface was evaluated by a push-in test. Additionally, after a healing period of 14 and 28 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed. RESULTS: The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for the rough surfaces (titanium: 36%/45%; zirconia: 45%/59%). Also, the push-in test showed higher values for the textured implant surfaces, with no statistical significance between titanium (34 N) and zirconia (45.8 N). CONCLUSIONS: Within the limits of the animal investigation presented, it was concluded that all tested zirconia and titanium implant surfaces were biocompatible and osseoconductive. The presented surface modification of zirconia implants showed no difference regarding the histological and biomechanical results compared with an established electrochemically modified titanium implant surface.