Effect of donor-specific blood transfusions on allotransplanted teeth in a monkey model: Histoquantification of periodontal healing.

BACKGROUND/AIMS: Pre-transplant blood transfusions have previously shown a positive effect on organ allograft survival in humans and various animal species. The aims of this study were, first, to evaluate the effect of pre-transplant donor-specific blood transfusions on periodontal healing of fully developed allotransplanted teeth in monkeys; and second, to investigate the immune response against donor antigens and to determine a possible correlation between alloimmune reactions and histopathological signs of rejection. MATERIAL AND METHODS: Twenty monkeys (Cercopithecus aethiops) were divided into ten pairs with similar sizes of incisors. One monkey in each pair gave three transfusions to the other monkey with 1-week intervals. One week after the last transfusion, each pair exchanged simultaneously a central maxillary incisor and a lateral mandibular incisor. The corresponding central maxillary and mandibular lateral incisors were autotransplanted to the contralateral sockets. All teeth were treated endodontically per-operatively. Histocompatibility was evaluated by mixed lymphocyte culture before the first transfusion, while alloantibodies and cell-mediated alloresponses were measured before transfusions and at 2 and 8 weeks after transplantation. All animals were sacrificed 8 weeks after tooth transplantation. Serial sections of the transplanted teeth were quantified histologically. RESULTS: Mixed lymphocyte cultures showed positive reactions in 19 of 20 cases, indicating incompatibility. The majority of the monkeys developed antibodies towards the tooth donor. Cell-mediated cytotoxicity was negative in all monkeys. Histoquantification revealed a mean score of 70% normal periodontal ligament (PDL) in autotransplanted teeth, with 5% ankylosis. The allografts had a mean score of 17% normal PDL and 63% ankylosis, with no significant influence of transfusion. However, in the mandibular grafts, a tendency towards a positive transfusion effect was seen. CONCLUSIONS: Donor-specific blood transfusion did not reduce ankylosis in tooth allografts. The healing of mandibular incisor tooth allografts was improved, but not that of maxillary incisors. Donor-specific antibodies showed no effect on the survival of allograft PDL.

Embolization of the middle meningeal artery in patients with chronic subdural hematoma-a systematic review and meta-analysis.

BACKGROUND: Chronic subdural hematoma (CSDH) remains a neurosurgical condition with high recurrence rate after surgical treatment. The primary pathological mechanism is considered to be repeated microbleedings from fragile neo-vessels within the outer hematoma membrane. The neo-vessels are supplied from peripheral branches of the middle meningeal artery, and embolization of MMA (eMMA) has been performed to prevent re-bleeding episodes and thereby CSDH recurrence. OBJECTIVE: To evaluate the published evidence for the effect of eMMA in patients with recurrent CSDH. Secondarily, to investigate the effect of eMMA as an alternative to surgery for primary treatment of CSDH. METHOD: A systematic review of the literature on eMMA in patients with recurrent CSDH was conducted. PubMed, Embase, and Cochrane databases were reviewed using the search terms: Embolization, Medial Meningeal Artery, Chronic Subdural Haematoma, and Recurrence. Furthermore, the following mesh terms were used: Chronic Subdural Haematoma AND embolization AND medial meningeal artery AND recurrence. Eighteen papers were found and included. No papers were excluded. The number of patients with primary CSDH and the number of patients with recurrent CSDH treated with eMMA were listed. Furthermore, the number of recurrences in both categories was registered. RESULTS: Eighteen papers with a total of 191 included patients diagnosed with CSDH treated with eMMA for primary and recurrent CSDH were identified. Recurrence rate for patients treated with eMMA for recurrent CSDH was found to be 2.4%, 95% CI (0.5%; 11.0%), whereas the recurrence rate for patients treated with eMMA for primary CSDH was 4.1%, 95% CI (1.4%; 11.4%). CONCLUSION: eMMA is a minimally invasive procedure for treatment of CSDH. Although this study is limited by publication bias, it seems that this procedure may reduce recurrence rates compared with burr hole craniostomy for both primary and recurrent hematomas. A controlled study is warranted.

Early decompressive surgery in patients with traumatic spinal cord injury improves neurological outcome.

BACKGROUND: The role and timing of a decompressive surgical intervention in patients with traumatic spinal cord injury (SCI) remain controversial. Given the impact of SCI on the individual and society, decompressive surgery to reduce the extent of tissue destruction and improving neurological outcome after initial spinal cord trauma are needed. OBJECTIVE: To evaluate any possible correlation between the time of a decompressive procedure after traumatic SCI and end-neurologic outcome for traumatic SCI patients. METHODS: A retrospective cohort study on patients with traumatic SCI in Western Denmark from 2010 to 2017. Data on date and time of injury and time of surgery and data on neurologic status at admission and one-year post-trauma were found in the Electronic Patients Journal (EPJ) and in paper journals. Patients were divided into 4 groups (< 6 h, < 12 h, < 24 h, and > 24 h) based on the time between injury and surgery. Further, patients were separated into two groups depending on whether they did or did not achieve neurological improvement one-year post-trauma. We used Fisher's exact test to compare the abovementioned groups to examine an eventual correlation between time from injury to operation and change in neurological outcome one-year post-trauma. RESULTS: Patients undergoing surgery < 24 h after trauma obtained a significantly better neurological outcome as compared with patients who underwent surgery > 24 h after trauma (p < 0.001). This result did not change for subgroups of incomplete SCI patients (p = 0.002). However, complete SCI patients operated < 24 h as compared with > 24 h did not obtain better outcome (p = 0.14). We did not find a statistically significant correlation when time from trauma to surgery was reduced further to < 6 or < 12 h post-trauma. Furthermore, stratification on patients undergoing surgery before and after 24 h was made regarding gender, completeness, and years of age. The groups did not differ concerning gender and SCI completeness, but significant difference in age was found (44 and 58 years of age, respectively, p < 0.001). The chance of improved outcome was significantly higher for patients < 50 years of age (42% versus 24%, p = 0.05). Patients under the age of 50 seemed to benefit from early intervention (50% improvement versus 23%); however, difference was not statistically significant (p = 0.08). In patients aged above 50, the trend was similar, but significant correlation was found (40% versus 16%, p = 0.05). CONCLUSION: The present study reports a beneficial effect of early decompression surgery, especially for incomplete SCI patients; however, surgical decision-making is complex, and all cases of acute spinal cord injury should be cautiously interpreted and handled on an individual basis.

Autotransplantation of teeth to the anterior maxilla: A systematic review of survival and success, aesthetic presentation and patient-reported outcome.

BACKGROUND/AIM: Autotransplantation of teeth to the anterior maxilla may be indicated after trauma or in patients with congenitally missing teeth. The aim of this systematic review was to report the current evidence concerning survival and success rate, aesthetic outcome, and patient-reported outcome of autotransplanted teeth to the anterior maxilla. MATERIALS AND METHODS: A MEDLINE search followed by an additional hand search was performed to identify relevant literature. All levels of evidence except case reports were considered. Any publication reporting on 10 or more autotransplanted teeth to the anterior maxilla, and written in English were eligible for this systematic review. RESULTS: The systematic search identified 95 abstracts. Thirty-seven full-text articles were evaluated of which 17 could finally be included. Data on survival and success rate of the transplants could be extracted from 11 studies. Survival rates ranged between 93% and 100% (weighted mean: 96.7%, median: 100%) after 9 months to 22 years of observation (median: 8.75 years). No consensus regarding definition of success criteria of the transplants could be found in the literature. Two and four studies contained data on aesthetic and patient-reported outcomes, respectively. In general, they reported favourable aesthetic results and high patient satisfaction. CONCLUSION: The current available evidence suggests a high survival rate after autotransplantation of teeth to the anterior maxilla. However, the level of evidence is low. Limited data on aesthetic and patient-reported outcomes warrant additional research in this field.

Loss of BDNF or its receptors in three mouse models has unpredictable consequences for anxiety and fear acquisition.

BDNF-induced signaling is essential for the development of the central nervous system and critical for plasticity in adults. Mature BDNF signals through TrkB, while its precursor proBDNF employs p75(NTR), resulting in activation of signaling cascades with opposite effects on neuronal survival, growth cone decisions, and synaptic plasticity. Accordingly, variations in the genes encoding BDNF and its receptors sometimes have opposing influences in psychiatric disorders, and despite the vast literature, consensus is lacking about the behavioral consequences of disrupting the activity of the BDNF system in mice. To dissect the behavioral traits affected by dysfunctional BDNF/TrkB vs. proBDNF/p75(NTR) activity, we studied Bdnf(+/-), Ntrk2(+/-), and Ngfr(-/-) mice in parallel with respect to exploratory behavior, anxiety, startle, and fear acquisition. Our data reveal that the effect of proBDNF/BDNF and its receptors on behavior is more complex than expected. Strikingly, receptor-deficient mice displayed increased risk-taking behavior in the open field and elevated plus maze, whereas lack of proBDNF/BDNF had the opposite effect on mouse behavior. On the other hand, although TrkB signaling is instrumental for acquisition of fear memory in an inhibitory avoidance experiment, lack of p75(NTR) or proBDNF/BDNF conferred increased memory in this task. Importantly, none of the genotypes displayed any deficits in startle reflex, indicating unimpaired response to shock. The combined data illustrate an apparent paradox in the role of the BDNF system in controlling complex behavior and suggest that the individual components may also engage independently in separate signaling pathways.

Transplantation of premolars as an approach for replacing avulsed teeth.

Autotransplantation of premolars to the anterior region subsequent to tooth loss represent a unique treatment method that has a number of advantages in comparison with other tooth substitution methods. A tooth transplant has a bone inducing capacity implying that lost labial bone is regenerated. Secondly the tooth precipitates growth of the alveolar procces and allows treatment to be performed at an early age (10-12 years) where the trauma incidence is at its maximum. Finally transplanted teeth can be moved orthodontically. These characteristics make implant solutions appealing in a number of situations. The procedure consist in selecting a premolar in a optimal root development stage which is approximately three fourths root formation where optimal pulp and periodontal ligament healing can be achieved in more than 90 percent of the cases. The tooth is later after slight crown remodeling restored with composite or a porcelain laminate. Four recent long-term studies have shown survival rates between 90-98 percent and a single long term study (33 years) showed a survival rate of 90 percent, a survival rate not surpassed by any other type of tooth replacement (fixed or removable prostetics, implants). In conclusion premolar transplantation should be considered in cases of early loss of a permanent tooth.

Tooth loss treatment in the anterior region: autotransplantation of premolars and cryopreservation.

Avulsed and lost anterior teeth are common in young people. Using autotransplantation, it is possible to move problems in dental arches to regions where they are more easy to solve orthodontically. Transplantation of premolars with three-quarter root formation or full root formation with wide-open apical foramina provides the best prognosis for long-term survival. This article describes the use of autotransplantation and orthodontic treatment, together with cryopreservation, in connection with complicated trauma in the anterior region of an 8-year-old girl.

Open or closed repositioning of mandibular fractures: is there a difference in healing outcome? A systematic review.

The clinical outcome of closed vs open reduction and rigid fixation was compared based on a systematic review of the literature. Ten non-randomized retrospective studies were found. In six of these ten studies, the complication rate was significantly increased when open reduction and plating was performed. In the remaining studies, a slightly elevated (but not significant) infection rate was found when compared with closed reduction. Altogether, an infection rate of 5.0% was found in the closed reduction group whereas 10.6% and 14.6% were found when open reduction was performed using either plates or wires. Nerve injuries were slightly increased when open reduction was found (although not significant). With regard to occlusal disturbances, no difference was found in the open and closed reduction group. Concerning overall complication problems, six of seven studies showed more problems after open than closed reduction. In conclusion, this literature review using retrospective studies has raised doubts regarding the superiority of open reduction and rigid splinting, compared to closed reduction and intermaxillary splinting. However, a bias concerning the preferential use of open reduction in case of more complicated fractures cannot be excluded, which might explain the differences found between the two procedures. Prospective, randomized clinical trials are needed to illuminate this problem.

Effect of early or delayed treatment upon healing of mandibular fractures: a systematic literature review.

The possible relation between treatment delay and healing complications in mandibular fracture treatment (excluding condylar fractures) was reviewed systematically. Twenty-two studies were identified. No randomized studies focused on the effect of immediate or delayed treatment. The main focus of most studies was surgical repositioning and internal skeletal fixation. The healing complications analyzed in this study were infection in the fracture line and malocclusion. Statistical analysis of the influence of treatment delay upon healing complications was possible in six studies. Four studies showed no significant difference between immediate and delayed treatment. One study showed a preference for healing for cases treated within 3 days, whereas another study indicated that treatment time between 3 and 5 days were optimal with the lowest rate of complications. Finally, a few studies identified confounding factors such as alcohol, drug abuse and/or non-compliance, factors which have been shown strongly to influence the likelihood of complications. A significant problem in this analysis was that rather few patients were actually treated on an acute basis (i.e. within 12 or 24 hours after injury), a fact which together with the lack of control of confounding factors made this analysis problematic. In conclusion, there is presently no strong evidence for either acute or delayed treatment of mandibular fractures in order to minimize healing complications; new studies including a substantial number of cases treated on an acute basis are very much needed.

A systematic review of prophylactic antibiotics in the surgical treatment of maxillofacial fractures.

PURPOSE: A systematic review was performed to find evidence for prophylactic administration of antibiotics in relation to treatment of maxillofacial fractures. METHODS: Four studies were retrieved that fulfilled most of the requirements of being randomized controlled clinical trials. RESULTS: An analysis of these studies showed a 3-fold decrease in the infection rate of mandibular fractures in the antibiotic treated groups compared with the control groups. A variety of antibiotics had been used with an apparently uniform effect. A "1-shot" regimen or a 1-day treatment course had a similar or perhaps even better effect than 7 days of treatment. No infections were related to condylar, maxillary, or zygoma fractures. CONCLUSION: A 1-shot or 1-day administration of prophylactic antibiotics seem to be the best documented to reduce infections in the management of mandibular fractures not involving the condylar region.