Anatomic variation of alveolar antral artery.

The alveolar antral artery (AAA) was unanimously encountered in a few available studies with an intraosseous course to anastomose with the infraorbital artery. We report here two cases in which dissection revealed an extraosseous placement of this artery, between the lateral wall of the maxillary sinus and the Schneiderian membrane. The frequency of occurrence of the intraosseous anastomosis should be so modified from 100% to < 100%. This arterial course over the Schneiderian membrane is important during surgical procedures: if it is identified preoperatively it can be avoided, or ligaturated, if not, it may be accidentally severed and uncomfortable haemorrhage may disturb the surgical procedure. In the first case reported here hybrid morphology of the AAA was also found, demonstrating that arterial anatomy should be considered with caution, on a case-by-case basis.

Infraorbital canal bilaterally replaced by a lateroantral canal.

The infraorbital canal (IOC) normally courses above the maxillary sinus in the orbit floor. During a retrospective study of cone beam computed tomography (CBCT) scans, we found a previously unknown variant of the IOC. The IOCs were absent, being replaced by lateroantral canals coursing around and not above the maxillary sinus to open at infraorbital foramina which were located above the second upper premolar teeth. On coronal multiplanar reconstructions, the lateroantral canals were located anatomically at the outer limit of the zygomatic recess of each maxillary sinus, while the upper wall of the sinus was devoid of any canal. Such rare variant should be kept in mind by dental practitioners and surgeons, as it can determine modifications of common procedures. In this regard, the anatomy of maxilla, as well as mandible, should be evaluated in CBCT on a case-by-case basis.

Numerical modelling of tooth enamel subsurface lesion formation induced by dental plaque.

Using a one-dimensional mathematical model that couples tooth demineralisation and remineralisation with metabolic processes occurring in the dental plaque, two mechanisms for subsurface lesion formation were evaluated. It was found that a subsurface lesion can develop only as the result of alternating periods of demineralisation (acid attack during sugar consumption) and remineralisation (resting period) in tooth enamel with uniform mineral composition. It was also shown that a minimum plaque thickness that can induce an enamel lesion exists. The subsurface lesion formation can also be explained by assuming the existence of a fluoride-containing layer at the tooth surface that decreases enamel solubility. A nearly constant thickness of the surface layer was obtained with both proposed mechanisms. Sensitivity analysis showed that surface layer formation is strongly dependent on the length of remineralisation and demineralisation cycles. The restoration period is very important and the numerical simulations support the observation that often consumption of sugars is a key factor in caries formation. The calculated profiles of mineral content in enamel are similar to those observed experimentally. Most probably, both studied mechanisms interact in vivo in the process of caries development, but the simplest explanation for subsurface lesion formation remains the alternation between demineralisation and remineralisation cycles without any pre-imposed gradients.

[Surgical management of malignant large bowel obstructions]. / Managementul chirurgical in urgenta al ocluziilor prin cancere colonice si rectale.

INTRODUCTION: Despite significant progress, the management of acute colonic obstruction still remains a challenging problem. The purpose of this study was represented by the evaluation of the clinical results of different techniques of resection for malignant colorectal (primary or staged) obstruction. METHODS: We performed a non-randomized clinical study. 590 patients with malignant colorectal occlusion who underwent surgery treatment an 3rd Surgical Clinic Cluj-Napoca between 1996-2005 were included. RESULTS: Patients with large bowel obstruction underwent one-stage primary resection with anastomosis in 267 cases or staged interventions in 323 cases. The groups were matched in: age, sex, comorbidities, tumor staging, serum preoperative levels of hemoglobin and proteins. The analysis of mortality and morbidity following surgical treatment for large bowel obstruction returned no significant difference among the two groups (p > 0.05). Moreover, the presented results showed a higher incidence of mortality (11.45% vs 9.33 %), morbidity (25.38% vs 14.6%) and increased hospitalization period (p = 0.029) among the patients that undergone seriate resections. CONCLUSIONS: One stage primary resections with anastomosis of the large bowel can be performed safely in case of emergency whenever patient comorbidities and local conditions do not stand as major restrictions.