The aim of this study was to compare the bone resorption differences between implant placement sites (IPS) and non-implant placement sites (NIPS) after autogenous block bone grafts in the anterior maxilla. Fourteen pa...The aim of this study was to compare the bone resorption differences between implant placement sites (IPS) and non-implant placement sites (NIPS) after autogenous block bone grafts in the anterior maxilla. Fourteen patients (58 edentulous sites) with alveolar atrophy in the anterior maxilla were treated with autogenous block bone grafts. CBCT examinations were performed at 1 month before surgery (T0), immediately after surgery (T1), 3 to 4 months after surgery (T2), 6 to 7 months after surgery before implant placement (T3), 12 to 13 months after surgery (T4), and the longest follow-up point (T5). Alveolar crestal and basal bone width (ACBW, ABBW), and alveolar bone height (ABH) were measured and divided into IPS (30 sites) and NIPS (28 sites). All results were compared by the Wilcoxon Signed Rank test. The bone resorption changes for both groups were the same. For these three parameters, ACBW didn’t change significantly from T2 to T3 and T4 to T5, ABBW didn’t change at every period from T2 to T5, and ABH didn’t change from T4 to T5. The bone resorption volume of ACBW and ABH in NIPS were more than in IPS after implant placement surgery, while the volume of ABBW was similar in both groups. At T5, the bone resorption percentages of ACBW, ABBW, and ABH were 25.57%, 16.85% and 43.84% in IPS, and 33.55%, 15.92% and 46.44% in NIPS. A more rapid loss of alveolar crest in NIPS resulted from implant placement surgery, and this reminded us of the importance of immediate implant placement.展开更多
Although short implants are seen as alternative treatments that require additional surgical techniques in posterior region, they can be applied to anterior maxilla and various studies are required on this subject. The...Although short implants are seen as alternative treatments that require additional surgical techniques in posterior region, they can be applied to anterior maxilla and various studies are required on this subject. The purpose of this study was to examine and compare the peak von Mises stress distributions in the crown, implant and abutment by using finite element analysis (FEA). Besides, a comparison of the implant-abutment connection types in the short implant with the FEA method was established. A short implant (4 × 5 mm) with a taper-lock connection and a regular implant (4 × 9 mm) with a screw connection were used in maxillary central incisor tooth area. Three different titanium abutments with 0?, 15? and 25? angles were used for abutments. In addition, in order to determine whether the stress change in short implants is due to the length of the implant-abutment connection, a screw was designed for a short implant and it was also evaluated in the same three angles. A total of three groups and nine models were generated. 114.6N load was applied to the cingulum area of the crown at an angle of 135? to the long axis of the crowns. A torque load of 25 Ncm was applied to the regular and short implant screw. Von Mises stress distributions of implants, abutments and crowns were evaluated by using FEA. Increased angle in implants increased von Mises stress values of implant, abutment and crown. Screw connection was found higher at all angles in short implants. Close values were found at different angles in taper-lock short implant crowns. The length and the angle in the bone of implant with the type of implant-abutment connection results in the accumulated stress values. Clinical Implications Taper implant-abutment connection system was found to be more promising in terms of stress accumulation in crowns. Although the amount of stress on the abutment increased due to the length of the implant in short implants, taper implant-abutment connection system slightly reduced related to this increase.展开更多
To provide an anatomical basis for clinical implant esthetics,we evaluated the morphology of the nasopalatine canal（NPC） and analyzed labial and interproximal bone anatomy at the maxillary anterior region.We sought ...To provide an anatomical basis for clinical implant esthetics,we evaluated the morphology of the nasopalatine canal（NPC） and analyzed labial and interproximal bone anatomy at the maxillary anterior region.We sought to investigate the effect of maxillary protrusion and tooth labiolingual inclination on labial bone anatomy in Chinese adults.Three dimensional（3D） images were reconstructed using cone-beam computed tomography（CBCT） images from 80 Chinese subjects and by SimPlant 11.04.The dimensions of the NPC,the thickness and profile of the labial bone,the width and height of the interproximal bone,angle sella-nasion-subspinale（SNA） and angle upper central incisor-nasion,subspinale（U1-NA） were measured.The incisive foramen of the NPC was markedly wider than its nasal foramen.The dimension of its labial bone wall demonstrated an increasing width from the crestal to apical measurements.The labial bone at the maxillary anterior region was rather thin,especially at 3 mm below the cemento-enamel junction（CEJ） and the mid-root level;the profile of the labial bone was more curved at the central incisor,and the interproximal bone became wider and shorter posteriorly.There were significant relationships between maxillary protrusion and labial bone profile,tooth labiolingual inclination and labial bone thickness（P 〈 0.02）.To achieve optimal esthetic outcome of implant,bone augmentation is necessary at the maxillary anterior region.For immediate or early placement at the maxillary anterior region,the implant should be located palatally to reduce labial bone resorption and marginal recession;its apex should be angulated palatally to avoid labial perforation at the apical region.To protect the NPC,implants at the central incisor region should be placed away from NPC.展开更多
文摘The aim of this study was to compare the bone resorption differences between implant placement sites (IPS) and non-implant placement sites (NIPS) after autogenous block bone grafts in the anterior maxilla. Fourteen patients (58 edentulous sites) with alveolar atrophy in the anterior maxilla were treated with autogenous block bone grafts. CBCT examinations were performed at 1 month before surgery (T0), immediately after surgery (T1), 3 to 4 months after surgery (T2), 6 to 7 months after surgery before implant placement (T3), 12 to 13 months after surgery (T4), and the longest follow-up point (T5). Alveolar crestal and basal bone width (ACBW, ABBW), and alveolar bone height (ABH) were measured and divided into IPS (30 sites) and NIPS (28 sites). All results were compared by the Wilcoxon Signed Rank test. The bone resorption changes for both groups were the same. For these three parameters, ACBW didn’t change significantly from T2 to T3 and T4 to T5, ABBW didn’t change at every period from T2 to T5, and ABH didn’t change from T4 to T5. The bone resorption volume of ACBW and ABH in NIPS were more than in IPS after implant placement surgery, while the volume of ABBW was similar in both groups. At T5, the bone resorption percentages of ACBW, ABBW, and ABH were 25.57%, 16.85% and 43.84% in IPS, and 33.55%, 15.92% and 46.44% in NIPS. A more rapid loss of alveolar crest in NIPS resulted from implant placement surgery, and this reminded us of the importance of immediate implant placement.
文摘Although short implants are seen as alternative treatments that require additional surgical techniques in posterior region, they can be applied to anterior maxilla and various studies are required on this subject. The purpose of this study was to examine and compare the peak von Mises stress distributions in the crown, implant and abutment by using finite element analysis (FEA). Besides, a comparison of the implant-abutment connection types in the short implant with the FEA method was established. A short implant (4 × 5 mm) with a taper-lock connection and a regular implant (4 × 9 mm) with a screw connection were used in maxillary central incisor tooth area. Three different titanium abutments with 0?, 15? and 25? angles were used for abutments. In addition, in order to determine whether the stress change in short implants is due to the length of the implant-abutment connection, a screw was designed for a short implant and it was also evaluated in the same three angles. A total of three groups and nine models were generated. 114.6N load was applied to the cingulum area of the crown at an angle of 135? to the long axis of the crowns. A torque load of 25 Ncm was applied to the regular and short implant screw. Von Mises stress distributions of implants, abutments and crowns were evaluated by using FEA. Increased angle in implants increased von Mises stress values of implant, abutment and crown. Screw connection was found higher at all angles in short implants. Close values were found at different angles in taper-lock short implant crowns. The length and the angle in the bone of implant with the type of implant-abutment connection results in the accumulated stress values. Clinical Implications Taper implant-abutment connection system was found to be more promising in terms of stress accumulation in crowns. Although the amount of stress on the abutment increased due to the length of the implant in short implants, taper implant-abutment connection system slightly reduced related to this increase.
文摘To provide an anatomical basis for clinical implant esthetics,we evaluated the morphology of the nasopalatine canal（NPC） and analyzed labial and interproximal bone anatomy at the maxillary anterior region.We sought to investigate the effect of maxillary protrusion and tooth labiolingual inclination on labial bone anatomy in Chinese adults.Three dimensional（3D） images were reconstructed using cone-beam computed tomography（CBCT） images from 80 Chinese subjects and by SimPlant 11.04.The dimensions of the NPC,the thickness and profile of the labial bone,the width and height of the interproximal bone,angle sella-nasion-subspinale（SNA） and angle upper central incisor-nasion,subspinale（U1-NA） were measured.The incisive foramen of the NPC was markedly wider than its nasal foramen.The dimension of its labial bone wall demonstrated an increasing width from the crestal to apical measurements.The labial bone at the maxillary anterior region was rather thin,especially at 3 mm below the cemento-enamel junction（CEJ） and the mid-root level;the profile of the labial bone was more curved at the central incisor,and the interproximal bone became wider and shorter posteriorly.There were significant relationships between maxillary protrusion and labial bone profile,tooth labiolingual inclination and labial bone thickness（P 〈 0.02）.To achieve optimal esthetic outcome of implant,bone augmentation is necessary at the maxillary anterior region.For immediate or early placement at the maxillary anterior region,the implant should be located palatally to reduce labial bone resorption and marginal recession;its apex should be angulated palatally to avoid labial perforation at the apical region.To protect the NPC,implants at the central incisor region should be placed away from NPC.
