Temporomandibular joint model: anatomic and radiologic comparison between rat and human

Purpose

The temporomandibular joint (TMJ) is a complex anatomic structure with various pathologies as fractures, ankylosis or degenerative diseases. Few animal models already exist and the current study aims at demonstrating that rats’ TMJ could be considered as a model, using anatomic dissection and radiology.

Methods

Five adult Wistar rats were dissected to explore the soft and bone anatomy of the TMJ. Five more adult Wistar rats underwent a CT scan to measure size and angles of the condyle.

Results

The angles between the condyle and the mandible corpus were observed to be different both in the sagittal plane (150° vs. 125° in human) and the transversal plane (140° vs. 180°). The condyle axis is sagittal and drop-shaped and there is no anterior eminence in rats’ temporal fossa. However, the other anatomic structures proved to be quite similar.

Conclusions

The temporomandibular joints in human and rat are close and only few anatomic differences have been reported. Rats thus appear as an interesting and cheap alternative to model TMJ.     

Acute promyelocytic leukaemia is characterized by stable incidence and improved survival that is restricted to patients managed in leukaemia referral centres: a pan‐Canadian epidemiological study

Timely diagnosis and care are major determinants of the outcome in acute promyelocytic leukaemia (APL), a malignancy whose incidence may be increasing. The Canadian Cancer Registry (CCR) and health system represent valuable settings to study APL epidemiology. We analysed the CCR, which contains data on all Canadians with APL. To provide clinical information lacking in the CCR, we obtained data from five leukaemia referral centres during a similar time period. Between 1993 and 2007, there were 399 APL in Canada. Age‐standardized incidence was 0·083/100 000 and was stable over time. The early death (ED) rate was 21·8% (10·6% in patients <50 years old and 35·5% for those aged >50 years), with no improvement over time. Five‐year overall survival (OS) was 54·6% (73·3% in patients <50 years; 29·1% older patients). In the referral cohort, 131 patients were diagnosed between 1999 and 2010. ED was 14·6% and 2‐year OS was 76·5%. Within this cohort, ED and OS improved over time, although advanced patient age remained an adverse determinant of OS. In Canada, APL incidence is unexpectedly low and temporally stable. ED was higher than reported in clinical trials, but similar to reports from other registries. In contrast, ED was lower in referral centres and improved with time.     

Clinical analysis and prognostic significance of haemophagocytic lymphohistiocytosis‐associated anaplastic large cell lymphoma in children

Haemophagocytic lymphohistiocytosis (HLH) has been rarely described in children treated for an anaplastic large‐cell lymphoma (ALCL). We evaluated the incidence, the clinical and histological characteristics and the prognosis of HLH associated‐ALCL. The medical, biological, cytological and histological data of patients treated for ALK‐positive ALCL in the paediatric department of a single institution between 1975 and 2008 were analysed and assessed for HLH according to diagnosis criteria of the Histiocyte Society. Data concerning a series of 50 consecutive children with ALCL were reviewed. HLH‐associated ALCL was observed in 12% of the patients. Lung involvement was significantly more frequent in HLH‐associated ALCL patients than in the group without HLH (P = 0·004), as well as central nervous system (CNS) and bone marrow involvement (P = 0·001 and P = 0·007 respectively). The histological subtype in children with HLH‐associated ALCL did not differ from that of the group without HLH. There was no significant difference between the two groups in 5‐year EFS and OS (P = 0·91 and P > 0·99 respectively). In conclusion, HLH is not rare in paediatric ALCL. Despite a high incidence of visceral, CNS and bone marrow involvement, HLH does not seem to exert a significant impact on outcome in children treated for ALCL.     

Blood Cells Attachment after Root Conditioning and PRP Application: An in vitro Study

Aim: Root conditioning is aimed at smear layer removal and at dental matrix collagen exposure, which may promote periodontal regeneration. This in vitro study assessed smear layer removal, collagen fiber exposure and the influence of PRP (platelet-rich plasma) application on adhesion of blood cells to the root surface using scanning electron microscopy (SEM). Materials and methods: Scaled root samples (n = 160) were set in five groups and conditioned with: group I - control group (saline solution); group II (EDTA 24%); group III (citric acid 25%); group IV (tetracycline hydrochloride 50 mg/ml); group V (sodium citrate 30%). Eighty samples were assessed using the root surface modification index (RSMI). The other eighty samples were set in two groups. The first group (n = 40) received PRP gel application with a soft brush and the second group (n = 40) received PRP application and then a blood drop. The fibrin clot formation was assessed in the first group and the blood cells adhesion was assessed in the second group using the BEAI (blood elements adhesion index). A previously trained, calibrated, and blind examiner evaluated photomicrographs. Statistical analysis was performed using the Kruskal-Wallis's and Dunn's tests. Results: Group III attained the best results for RSMI and BEAI. Moreover, it was the only group showing fibrin clot formation. Conclusion: Citric acid was the most efficient conditioner for smear layer removal, collagen fiber exposure and blood cell adhesion. Moreover, it was the only group showing fibrin clot formation after PRP application. Clinical significance: This study demonstrated that root conditioning followed by PRP application may favor blood cell adhesion on root surface which may optimize periodontal healing. Keywords: Root conditioning, Blood, Platelet-rich plasma, Smear layer, Edetic acid, Citric acid, Tetracycline, Laboratory research. How to cite this article: Dantas AAR, Fontanari LA, Ishi EP, Leite FRM, Zandim DL, Abi Rached RSG, Sampaio JEC. Blood Cells Attachment after Root Conditioning and PRP Application: An in vitro Study. J Contemp Dent Pract 2012;13(3):332-338. Source of support: The study was financially supported by CAPES-Coordination for the Improvement of Higher Education Personnel (Brasilia, DF, Brazil). Conflict of interest: None declared.     

Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

Objective

The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning.

Material and Methods

A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained.

Results

Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples.

Conclusion

Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning.     

Negative-pressure wound therapy and laparoscopic omentoplasty for deep sternal wound infections after median sternotomy

Deep sternal wound infection remains one of the most serious complications in patients who undergo median sternotomy for coronary artery bypass surgery.We describe our experience in treating 6 consecutive patients with our treatment protocol that combines aggressive débridement, broad-spectrum antibiotics, negative-pressure wound therapy, omentoplasty with laparoscopically harvested omentum, and the use of bilateral pectoral muscle advancement flaps.The number of débridements needed in order to attain clinically clean wounds and negative cultures varied between 1 and 10, with a median of 5. The length of stay after omentoplasty and bilateral pectoral muscle advancement flap placement varied between 11 and 22 days. One of the 6 patients developed a small wound dehiscence that was treated conservatively. No bleeding related to vacuum-assisted closure therapy was identified. Three patients had pneumonia. Two of the 3 patients had an episode of acute renal failure. The 30-day mortality rate was zero, although 1 patient died in the hospital 43 days after the reconstructive surgery, of multiple-organ failure due to pneumonia that was induced by end-stage pulmonary fibrosis. No patient died between hospital discharge and the most recent follow-up date (4-12 mo). Late local follow-up results, both functional and aesthetic, were good.We conclude that negative-pressure wound therapy-in combination with omentoplasty using laparoscopically harvested omentum and with the use of bilateral pectoral advancement flaps-is a valuable technique in the treatment of deep sternal wound infection because it produces good functional and aesthetic results.     

Manual skill,hand skill asymmetry,and cognitive performances in young children

A total of 1022 children aged 3 to 6 years were examined in their preschools and 27% of them were followed up for 2 years. A computerised version of the peg‐moving task was used repeatedly to assess hand skill of the dominant and the nondominant hand. Cognitive performance was repeatedly evaluated by tasks involving speech, vocabulary, phonological memory, and visual‐spatial skills. Results showed that: (i) age, sex, and handedness effects on hand skill asymmetry generally confirmed previous reports, especially by Annett (2002); (ii) visual‐spatial and vocabulary tasks were significantly related to hand skill but speech and phonological memory tasks were not, and the role of the dominant and nondominant hand were similar; (iii) overall, manual laterality indexes were only weakly associated to some cognitive abilities; (iv) early manual skill was more strongly associated to cognitive tasks than later manual skill. These results fit the assumption of a significant role of early manual behaviour in aspects of cognitive development not relying exclusively on phonology, and raise questions about cognitive development and rehabilitation of children with early occurring manual deficiencies.