Histomorphic-metric evaluation of an implant retrieved from human maxilla after 13 years.

Fixture fracture is the most catastrophic failure of implant components because it usually causes the loss of the implant. Nevertheless, the osseointegrated fractured implants represent a very useful opportunity to study in humans the effects of loading to the peri-implant bone microstructure. The aim of the present study was to evaluate the interplay between microstructure and function of the bone around an implant retrieved from human maxilla after 13 years. There was 1 fractured Dental Implant Line (sand blasted surface from a patient placed in the anterior region of the maxillary bone (2.1) after a bone augmentation procedure, and it was processed for histology. The specimen was analyzed under the scanning electron microscope (SEM), the confocal scanning laser microscope (CSLM) and brightfield light microscope (LM) equipped with circularly polarized light (CPL). The BIC rate of the implant retrieved after 13 years was (mean ±SD) 68.7 ± 3.7. The crestal bone down the implant platform damage appeared to be under modeling process. The transverse collagen fiber orientation (CFO) (mean ±SD) under the lower flank of the threads was 20.4 ± 3.5 x 10(4) pixel while the longitudinal CFO was 19.8 ± 2.8 x 10(4) pixel (P>.05). In the inter-threads region the transverse CFO (mean ±SD) was 15.0 ± 4.0 x 10(4) pixel while the longitudinal CFO was 21.4 ± 3.0 x 10(4) pixel (P>.05). The osteocytes numbers (mean ±SD) was 130 ∓ 34. Under SEM with back scattered electrons (BSE) signal the peri-implant bone appears mainly lamellar and highly mature with several osteons organized in the implant inter-threads areas. The fracture of the implant was most probably correlated to a fatigue of the material mainly associated to a damage of the internal coil. Surprisingly, it was noted a lack of implant site-specific CFO of the bone extracellular matrix facing the threaded dental implant notwithstanding the high level of BIC rate.

Histomorphometric evaluation of an immediately loaded implant retrieved from human mandible after 2 years.

The aim of the present study was to evaluate the interplay between microstructure and function of the bone around an immediately loaded implant retrieved from human maxilla after 23 months due to fracture. A spiral implant of 3.3 mm x 15 mm was placed in a male 53 years old in the anterior region of the mandible bone (4.1) and it was processed for histology. The specimen was analyzed under the confocal scanning laser microscope (CSLM) and brightfield light microscope (LM) equipped with circularly polarized light (CPL). The BIC rate was 76.7 ± 4.9 (mean ±SD). Many cement lines indicates an high remodeling rate of the bone. The transverse collagen fiber orientation (CFO) (mean±SD) under the lower flank of the thread near the tread tip was 55.2 ± 4.8 x 10(4) pixel while the longitudinal CFO was 45.8 ± 2.3 x 10(4) pixel (P<.05). In the inter-threads region the transverse CFO (mean ±SD) was 36.4 ± 2.4 x 10(4) pixel while the longitudinal CFO was 65.6 ± 6.5 x 10(4) pixel (P<.05). The osteocytes numbers (mean ±SD) was 205 ± 45 in the peri-implant bone and 144 ± 53 in the native bone (P=.007). After 2-years of loading the SLA spiral implant was well osseointegrated but still surrounded by woven bone. The osteocytes density was significantly higher in the peri-implant bone than in the native bone. The transverse collagen fibers were significantly associated with the lower flank of the implant threads, while the longitudinal collagen fibers were more represented in the straight surface of the implant. The implant fracture was correlated to crestal bone resorbing and subsequent fatigue yielding.

Calcium sulfate stimulates pulp stem cells towards osteoblasts differentiation.

Calcium sulfate (CaS) is a highly biocompatible material and enhances bone formation in vivo. However, how CaS alters osteoblast activity to promote bone formation is poorly understood. To study how CaS can induce osteoblast differentiation in mesenchymal stem cells, the expression levels of bone related genes and mesenchymal stem cells marker were compared in normal osteoblasts and dental pulp stem cells, using real time Reverse Transcription-Polymerase Chain Reaction. Gene differentially expressed between the two cells type were the trascriptional factor RUNX2, osteopontin (SPP1), COL1A1 (collagen type 1α1) and alkaline phosphatase (ALPL). The obtained results demonstrated that CaS strongly influences the behavior of DPSCs in vitro enhancing proliferation, differentiation and deposition of matrix.

Polylactide-polyglycolide resorbable plates stimulates adipose tissue-derived stem cells towards osteoblasts differentiation.

Polylactide, polyglycolide materials or devices have been utilized routinely during maxillofacial, craniofacial, and orthopaedic reconstructive surgical procedures.(1) These materials combine the benefits of rigid fixation with the advantages of biodegradation, avoiding the need for implant removal and minimizing the risk of other complications.(2) To study how polylactide, polyglycolide acids plates (PLPG plates) can induce osteoblast differentiation and proliferation in mesenchymal stem cells, the expression levels of bone related genes (RUNX2, SP7, ALPL, SPP1, COL1A1, COL3A1 and FOSL1) and mesenchymal stem cells marker (ENG) were measured in adipose derived stem cells (ADSCs) and normal osteoblast (NO) cultivated on PLPG plates after 15 and 30 days of treatment using real time Reverse Transcription-Polymerase Chain Reaction. Significantly differentially expressed genes among ADSCs and NO were SP7, ENG, FOSL1, RUNX, ALPL and SPP1 in the first 15 days of treatment and SP7, ENG FOSL1, COL3A1 COL1A1, SPP1 and ALPL after 30 days. The present study demonstrated that PLPG plates strongly influences the behavior of ADSCs in vitro by enhancing proliferation, differentiation and deposition of matrix.

Overdentures on implants placed in bone augmented with fresh frozen bone.

AIM: In the last decade several studies have been performed to evaluate the clinical outcome of one or two stage loaded implants supporting overdentures. Since fresh frozen bone (FFB) has an ever-increasing number of clinical applications and few reports are available on implants inserted into FFB, we performed a retrospective study on fixtures inserted in FFB and bearing overdentures. METHODS: In the period between December 2003 and December 2006, 17 patients (14 females and 3 males with a median age of about 56 years) were grafted and 60 implants inserted thereafter. A total of 17 overdentures were delivered: 8 in the mandible and 9 in the maxilla. Multiple implant systems were used: 22 Double etched, 7 SLA, 9 Anodic oxidized, and 22 CaPo4 ceramic-blasted. Implant diameter ranged from 3.25 to 4.3 mm and length from 11.5 to 16.0 mm. Implants were inserted to replace 23 incisors, 9 cuspids, 20 premolars and 8 molars. RESULTS: No implants were lost (i.e., survival rate=100%) and no differences were detected among the studied variables. Kaplan Meier algorithm and Cox regression did not reveal any statistical differences among the studied variables also as regards the success rate. CONCLUSION: Implants inserted FFB and bearing overdentures have a high survival rate and success rates, which are comparable to those of implants inserted in non-grafted bone. FFB bone is a reliable material for alveolar ridge augmentation. No difference was detected among removable prostheses supported by two or more implants.

Positioning of a contextual implant along with a sinus lift anchored with a block of heterologous bone.

During a sinus lift procedure the main requirement in order to position an implant is to have a maxillary sinus floor cortical bone thick enough to guarantee a primary stability in the implant inserted. In this way, the healing process is facilitated and osseointegration of the titanium surface may occur simultaneously, thus reducing the waiting time for the engraftment of the implant into the body. Unfortunately, these conditions are not always present. Hence, the need of developing an alternative approach that could simultaneously allow to perform sinus floor elevation along with an implant placement. Here we present the case of a 62-year-old patient that requires implant-prosthetic rehabilitation from 1.2 to 1.6 at diagnosis. In this study, we reported a novel application derived from the use of a heterologous bone scaffold (SmartBone@) in a sinus lift procedure. We showed the successful implant along with sinus lift with SmartBone@, both at the time of the surgery and after follow-up of the patient at 10 months from the implant. The possibility to perform simultaneously the contextual implant along with sinus lift dramatically reduced the waiting time for the patient of minimum 5-6 months required for osseointegration of the grafted biomaterials, before performing the implant procedure. This surgery represents an advance both in terms of medical technique and as life-benefit for the patient.