Determination of the most appropriate stress distribution by Finite Element Analysis in fixation with resorbable screws after Bilateral Sagittal Split Ramus Osteotomy surgery

"nBackground and Aim: Due to the complications associated with fixation by Titanium screws and plates in Bilateral Sagittal Split Ramus Osteotomy (BSSRO) surgery, the use of resorbable polymers has been increasingly recommended. Since there are not enough studies on this issue, this study aimed to assess the most appropriate stress distribution in fixation with resorbable screws after BSSRO surgery by Fnite Element Analysis (FEA)."nMaterials and Methods: This experimental study was performed on simulated human mandible using Ansys and Catia softwares. The osteotomy line was applied to the simulated model and experimental loads of 75, 135 and 600 N were respectively exerted according to the natural direction of occlusal force. The distribution pattern of stress was assessed and compared for fixation with one resorbable screw, two resorbable screws in vertical pattern, two resorbable screws in horizontal pattern, three resorbable screws in L pattern and three resorbable screws in inverted backward L pattern using Ansys software."nResults: Among the four simulated fixations, L pattern showed the highest primary stability. Two screws in vertical pattern were also associated with sufficient primary stability and less trauma and cost for patients. One screw did not provide enough stability under 600 N."nConclusion: Polymer-based resorbable screws (polyglycolic acid and D, L polylactide acid) provided satisfactory primary stability in BSSRO surgery

Trigeminocardiac reflex during Le Fort I osteotomy: a case-crossover study

Objective. The present study aimed to assess the occurrence of trigeminocardiac reflex (TCR) during Le Fort I osteotomies. Study design. This case-crossover study included 25 Le Fort I osteotomy candidates without systemically compromising conditions. Mean arterial blood pressure and pulse rate values were recorded before downfracture (DF) (MABP1, PR1), during DF (MABP2, PR2), and after DF (MABP3, PR3). The data were analyzed using repeated measure ANOVA tests (alpha = 0.05). Results. PR1 and PR3 were significantly higher than PR2 (P < .001). MABP2 value was significantly lower compared with MABP1 and MABP3 values (P < .001). PR2 and MABP2 showed a mean decrease of 6.5% and 9.7% compared with PR1 and MABP1, respectively. Conclusion. Different values have been suggested for TCR. Considering the limitations, the present study may suggest a revision of the values or descriptions for TCR, at least in maxillofacial Le Fort I osteotomy. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 110: 178-181

Polietilen Glikol Hidrojel Dural Bariyer Nörotoksisitesinin Değerlendirilmesi

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