Freeze-dried homogeneous and heterogeneous bone for sinus augmentation in sheep. Part I: histological findings

Freeze-dried bone has been reported to possess an osteogenetic potential, i.e. to be osteo-inductive or osteoconductive depending on the grafted site. In this animal study homogeneous demineralized freeze-dried bone from the sheep (s-DFDB) and heterogeneous human demineralized freeze-dried bone (h-DFDB) used for single-stage sinus elevation were examined for their potential to improve bone-to-implant bonding. In 72 sinuses of 36 adult female mountain sheep Schneider's membrane was elevated from the local bone through an extra-oral approach and two cylindrical plasma-flame sprayed titanium implants were inserted in the lateral wall of each sinus. At the same time 18 sinuses were reinforced with s-DFDB, another 18 with h-DFDB and yet another 18 with autogenous cancellous bone from the iliac crest. In 18 animals the subantral space remained ungrafted. At each follow-up date, i.e. at 12, 16 and 26 weeks, 12 animals were re-examined and one randomly selected implant from each sinus was analyzed histologically and histomorphometrically. With both s-DFDB and h-DFDB extensive fragmentation and disintegration were seen side by side with sporadic areas of remineralization. These were mainly located in the vicinity of the local host bone and coalesced over time to be ultimately replaced and consolidated by woven bone. But most of the h-DFDB/s-DFDB particles continued to be embedded in abundant collagenous connective tissue and were surrounded by mononucleated and multinucleated giant cells, ultimately causing extensive resorption. The mean bone-to-implant contact length was 16.4% of the implant surface for s-DFDB, 16.9% for h-DFDB, 32.8% for autogenous bone and 22.2% in ungrafted controls. In the autogenous bone group the mean bone-to-implant contact length progressively increased with increasing contact time. In the control group, by contrast, the mean bone-to-implant contact length initially increased in the first two follow-up periods, but dropped again at 26 weeks. Both in the h-DFDB and the s-DFDB group the percent bone contact area was lower at 16 weeks than at 12 weeks but increased again by 26 weeks. In apical implant sections, s-DFDB produced significantly less bone-to-implant contact than autogenous cancellous bone from the iliac crest. In basal implant sections, both DFDB-grafted groups did significantly less well than the two control groups. The results of this experimental study showed that DFDB homografts and heterografts cannot be recommended alone instead of cancellous autografts from the iliac crest for augmenting the maxillary sinus in single-stage sinus elevations. Longer follow-up times than in the present study may perhaps show better results at the bone-implant interface.     

Focal dermal hypoplasia: a case report and literature review

Focal dermal hypoplasia (FDH), also known as Goltz-Gorlin syndrome, is an autosomal dominant disease affecting tissues derived from the ectoderm and mesoderm. Knowledge and early diagnosis of the craniofacial alterations commonly found in patients with FDH provide oral health care professionals with effective preventive and therapeutic tools. This article aims to review the craniofacial characteristics present in FDH and the main systemic manifestations that have implications for dental management, while presenting a new case of the syndrome with novel oral findings.     

Prototyping for surgical and prosthetic treatment

Techniques of rapid prototyping were introduced in the 1980s in the field of engineering for the fabrication of a solid model based on a computed file. After its introduction in the biomedical field, several applications were raised for the fabrication of models to ease surgical planning and simulation in implantology, neurosurgery, and orthopedics, as well as for the fabrication of maxillofacial prostheses. Hence, the literature has described the evolution of rapid prototyping technique in health care, which allowed easier technique, improved surgical results, and fabrication of maxillofacial prostheses. Accordingly, a literature review on MEDLINE (PubMed) database was conducted using the keywords rapid prototyping, surgical planning, and maxillofacial prostheses and based on articles published from 1981 to 2010. After reading the titles and abstracts of the articles, 50 studies were selected owing to their correlations with the aim of the current study. Several studies show that the prototypes have been used in different dental-medical areas such as maxillofacial and craniofacial surgery; implantology; neurosurgery; orthopedics; scaffolds of ceramic, polymeric, and metallic materials; and fabrication of personalized maxillofacial prostheses. Therefore, prototyping has been an indispensable tool in several studies and helpful for surgical planning and fabrication of prostheses and implants.     

Patients' satisfaction after surgical facial reconstruction or after rehabilitation with maxillofacial prosthesis

The matching of the aesthetic, functional, and psychosocial results of a facial deformity may produce devastating effects in its carriers, especially if the lesion is extensive or the treatment is aggressive. Because of this, the objective of the present article was to evaluate patient's satisfaction rating after surgical facial reconstruction or rehabilitation with oral and maxillofacial prosthesis, by means of reviewing the literature.     

Quantitative tissue pH measurement during cerebral ischemia using amine and amide concentration-independent detection (AACID) with MRI

Tissue pH is an indicator of altered cellular metabolism in diseases including stroke and cancer. Ischemic tissue often becomes acidic due to increased anaerobic respiration leading to irreversible cellular damage. Chemical exchange saturation transfer (CEST) effects can be used to generate pH-weighted magnetic resonance imaging (MRI) contrast, which has been used to delineate the ischemic penumbra after ischemic stroke. In the current study, a novel MRI ratiometric technique is presented to measure absolute pH using the ratio of CEST-mediated contrast from amine and amide protons: amine/amide concentration-independent detection (AACID). Effects of CEST were observed at 2.75 parts per million (p.p.m.) for amine protons and at 3.50 p.p.m. for amide protons downfield (i.e., higher frequency) from bulk water. Using numerical simulations and in vitro MRI experiments, we showed that pH measured using AACID was independent of tissue relaxation time constants, macromolecular magnetization transfer effects, protein concentration, and temperature within the physiologic range. After in vivo pH calibration using phosphorus (³¹P) magnetic resonance spectroscopy (³¹P-MRS), local acidosis is detected in mouse brain after focal permanent middle cerebral artery occlusion. In summary, our results suggest that AACID represents a noninvasive method to directly measure the spatial distribution of absolute pH in vivo using CEST MRI.     

Identification of psychopathological course trajectories in schizophrenia

Course trajectory analyses have been performed primarily for treatment response in acute episodes of schizophrenic disorders. As yet, corresponding data for the long-term course are lacking. Within a multicenter prospective observational study, 268 patients with schizophrenia were assessed at discharge from hospital and followed up after 6, 12, 18, and 24 months. A latent class growth analysis was performed on the scores from the Positive and Negative Syndrome Scale (PANSS). A two-class conditional latent class model showed the best data fit (Entropy: 0.924). The model divided the sample into a group with amelioration in all PANSS subscales (60%) and a group with stable positive/negative and deteriorating general psychopathology symptoms (40%). Global functioning (GAF score), gender, age, living situation and involuntary admission predicted course trajectory class membership. The model was predictive of significant differences between the two groups in health care service costs and quality of life. The results underline the heterogeneous course of the illness, which ranged from amelioration to deterioration over a 2-year period. Statistical models such as trajectory analysis could help to identify more homogenous subtypes in schizophrenia.