La structure osseuse de la branche montante de la mandibule

Osseous structure of the ramus of mandible (RM) is of a practical clinical significance. Osteosynthesis of fractured segments and the success of the sagittal or the horizontal ramus split osteotomy depends on the cortical bone disposition and thickness.After morphometric investigations of the RM, conducted on 70 mandibles of adults, consecutive horizontal and frontal sections were made. On these sections, the cortical layer was studied and the cortical bone thickness was measured at four previously marked points.In the regard of morphometry, the significant datum is that nearly half of all the cases is grouped round the mean value of any parameter.Cortical bone is continuous and its two main sheets are the buccal and the lingual cortical plates. In its entirety, the buccal cortical plate is thicker than the lingual. The thickness of both cortical plates increases in the direction from the coronoid process to the angle of mandible.L’ostéosynthèse de la branche montante de la mandibule et le succès de l’ostéotomie sagittale ou horizontale de cette branche dépendent de la disposition et de l’épaisseur de sa couche osseuse compacte. Les examens morphométriques qui ont été faits sur 70 mandibules des sujets adultes montrent que presque la moitié de tous les cas se groupent autour de la valeur moyenne des paramètres mesurés (schéma 1 et tableau I).Sur les coupes horizontales et frontales, l’épaisseur des lames compactes buccale et linguale a été mesurée dans certains points prédéterminés et il a été établi que la lame buccale est toujours plus épaisse (schéma 2 et tableau II)

Assessing the effect of multibracket appliance treatment on tooth color by using electronic measurement

Abstract Background The purpose of this study was to investigate how tooth color is affected by multibracket appliance (MBA) treatment. Methods The color of teeth #14 to #24 of 15 patients with MBA was measured on body and gingival tooth segments using the spectrophotometer Shade Inspector™. Colors of both segments were recorded before start of MBA treatment (baseline T0), end of MBA treatment (T1; 2 years ±0.3), and 3 months after T1 (T2). A 2D color system and a 3D system served as reference systems. Multilevel models were used to analyze color change within segments and to compare the difference in color change between segments (treatment effect). Results 2D system. Changes within tooth segments from T0 to T2 were at worst 2.0 units (ΔE in the gingival segment), which is less than the threshold of 2.7 units for a clinically meaningful difference. Confidence intervals for the treatment effect indicated no clinically important differences in color change between body and gingival segments. 3D system. Changes within tooth segments from T0 to T2 were at worst 2.3 units (ΔE in the body segment), which is less than the threshold of 2.7 units for a clinically meaningful difference. Confidence intervals for the treatment effect indicated no clinically important differences in color change between body and gingival segments. Thus, MBA treatment did not lead to clinically relevant changes in tooth color. Conclusion Within the limitation of this study the MBA treatment can be seen as a safe method with respect to tooth color