Early loading of ITI implants supporting maxillary fixed full-arch prostheses

Objective: To evaluate the predictability of the early‐loaded sand‐blasted, large‐grit and acid‐etched (SLA) implants supporting maxillary‐fixed full‐arch prostheses. Material and methods: Ninety‐one ITI SLA implants were placed in 12 edentulous maxillae. The impressions were taken at 4 weeks post‐surgery. The abutments were tightened and the final fixed prostheses were cemented at 6 weeks after implant placement. Resonance frequency analysis (RFA) was conducted on the day of the surgery, at 4 and 6 weeks post‐surgery. Panoramic radiographs were taken immediately after surgery, at 4 weeks post‐surgery, immediately after prostheses attachment (baseline) and at the yearly follow‐ups. Results: The survival rate of implants was 98.90%. The success rate of prostheses was 100% during the follow‐ups. The radiographic result showed no radiolucency around the implants and the marginal bone level revealed no significant resorption compared with the baseline. The marginal bone level remained coronally beyond the first thread. The RFA results revealed Implant Stability Quotient (ISQ) values of 63.44±4.32, 57.14±4.25 and 66.43±3.78 for the three time points. Conclusions: The findings of this study indicated that early loading of ITI implants supporting maxillary fixed full‐arch prostheses should be predictable.     

Assessment of bone mineral density in the jaws and its relationship to radiomorphometric indices

Objectives

The aim of this study was to evaluate maxillary, mandibular and femoral neck bone mineral density using dual energy X-ray absorptiometry (DXA) and to determine any correlation between the bone mineral density of the jaws and panoramic radiomorphometric indices.

Methods

49 edentulous patients (18 males and 31 females) aged between 41 and 78 years (mean age 60.2 ± 11.04) were examined by panoramic radiography. Bone mineral density (BMD) of the jaws and femoral neck was measured with a DXA; bone mineral density was calculated at the anterior, premolar and molar regions of the maxilla and mandible.

Results

The mean maxillary molar BMD (0.45 g cm⁻²) was significantly greater than the maxillary anterior and premolar BMD (0.31 g cm⁻², P < 0.05). Furthermore, the mean mandibular anterior and premolar BMD (1.39 g cm⁻² and 1.28 g cm⁻², respectively) was significantly greater than the mean mandibular molar BMD (1.09 g cm⁻², P < 0.01). Although BMD in the maxillary anterior and premolar regions were correlated, BMD in all the mandibular regions were highly correlated. Maxillary and mandibular BMD were not correlated with femoral BMD. In addition, mandibular cortical index (MCI) classification, mental index (MI) or panoramic mandibular index (PMI) values were not significantly correlated with the maxillary and mandibular BMDs (P > 0.05).

Conclusions

The BMD in this study was highest in the mandibular anterior region and lowest in the maxillary anterior and premolar regions. The BMD of the jaws was not correlated with either femoral BMD or panoramic radiomorphometric indices.     

平行于功能牙合平面水平向后牵引猴上颌骨矫形作用的三维有限元研究

目的 采用螺旋CT断层扫描原始DICOM数据,建立猴颅面复合体三维有限元模型,并对其在后牵引矫形力载荷条件下的生物力学特性进行初步探讨。方法 选用混合牙列期雄性恒河猴1只,行螺旋CT扫描,建立猴颅面复合体三维有限元模型。利用ANSYS 12.1软件分析不同大小后牵引矫形力作用下,上颌骨各标志点在三维方向上的位移变化。结果 随着力值的加大,各标志点的位移变大,位移与力值大小呈线性关系。其中,在x轴方向,各点的位移均较小;在y轴方向,各点的位移呈现较大的变化,方向沿y轴向后,而且随力值加大,位移增加明显;在z轴方向,上颌前部的上齿槽座点和前鼻棘点位移向下,上颌骨后部的后鼻棘点位移向上。结论 水平向后牵引对上颌骨有明显的后移作用且上颌产生顺时针方向的旋转,但对上颌宽度产生的影响较小。     

上颌骨成釉细胞纤维瘤1例

患者,女,22岁,以“右面部肿胀2个月”为主诉于2012年6月21日入院。专科查体：右侧面部膨隆,右上颌前庭沟膨隆,右侧硬腭膨隆（图1）,压痛（-）,上颌牙齿列齐,无缺损,无活动,无张口受限,眼球活动及视力正常,双侧鼻腔通畅。     

Maxillary ameloblastoma. Case report and review of the literature

A case of maxillary ameloblastoma is presented. A non-healing, asymptomatic ulcerative lesion in the maxillary tuberosity region did not respond following relief of physical irritation. The clinical appearance of the lesion was compatible with that of a malignant tumour, but the histopathology was consistent with a diagnosis of ameloblastoma of the maxilla.     

Clinical outcome of 103 consecutive zygomatic implants: a 6-48 months follow-up study

The purpose of this study was to evaluate retrospectively, after a period of 6-48 months follow-up of prosthetic loading, the survival rate of 103 zygomatic implants inserted in 55 totally edentulous severely resorbed upper jaws. Fifty-five consecutive patients, 41 females and 14 males, with severe maxillary bone resorption were rehabilitated by means of a fixed prosthesis supported by either 1 or 2 zygomatic implants, and 2-6 maxillary implants. This retrospective study calculated the success and survival rates at both the prosthetic and implant levels. Out of 55 prostheses, 52 were screwed on top of the implants, while 3 were modified due to loss of standard additional implants and transformed in semimovable prosthesis. Although osseointegration in the zygomatic region is difficult to evaluate, no zygomatic implant was considered fibrously encapsulated and they are still in function. This study confirms that zygoma bone can offer a predictable anchorage and support function for a fixed prosthesis in severely resorbed maxillae.     

The number of implants required to support a maxillary overdenture: a systematic review and meta-analysis

Purpose

The number of implants needed to support a maxillary overdenture is still a controversial issue. The aim of this systematic review was to investigate the number of implants required to support a maxillary overdenture in order to obtain optimal treatment outcomes in terms of implant survival, overdenture longevity and patient satisfaction.

上颌后牙区骨膨胀技术结合上颌窦闭式提升术植入CDIC种植体的探讨

目的：探讨一种创伤较小的后牙牙槽脊增宽，同期植入CDIC种植体的方法。方法：通过使用后牙骨挤压骨膨胀的技术获得初期固位。结果：两例病例获得成功，近期成功率达100％。结论：上颌后牙区骨挤压骨膨胀技术结合上颌窦闭式提升术植入CDIC种植体是一种解决后牙区骨萎缩的方法。     

Chondrosarcoma of the maxilla. Case report

Chondrosarcoma is a rare malignant neoplasm of the jaws. The diagnosis of this lesion is mainly based on the histopathological appearance. A case of chondrosarcoma of the maxilla is reported. The origin of this rare tumour in the maxilla, a bone with exclusive membranous ossification, is discussed.     

Histomorphometric and fluorescence microscopic analysis of bone remodelling after installation of implants using an osteotome technique

The influence of the osteotome technique on the osseointegration of rough-surfaced stepped cylinder implants (Frialit)-2) was compared to conventional preparation of the implant site in an animal model. A total of 104 implants were placed into the distal femoral condyle of 52 New Zealand white rabbits. This region contains sufficient trabecular bone for implant placement. The implant site was prepared either by the osteotome technique or by conventional technique with drills as a control group. During the healing period polychromatic fluorescence labelling was performed with four different fluorescent dyes. After 2, 4 and 8 weeks, the implants were removed with the surrounding bone. The sample preparation was done using the 'sawing and grinding' technique. Ground sections 100 microm thick were used for fluorescence microscopic analysis; 30- microm-thick ground sections were examined histomorphometrically. After 2 weeks the bone-to-implant contact ratio was 55.0 +/- 7.1% for the osteotome technique and 29.2 +/- 4.8% for the control group (P < 0.0005). After 4 weeks, the bone-to-implant contact ratio was still significantly better for the osteotome technique (bone-to-implant contact ratio osteotome technique 71.1 +/- 7.2%, bone-to-implant contact ratio control 59.0 +/- 6.3%, P = 0.003). Eight weeks after implant placement the bone-to-implant contact ratio was still better for the osteotome technique compared to the conventional implant placement. However it was no longer statistically significant. The qualitative fluorescence microscopic examination showed an earlier and stronger signal for the osteotome technique than the control group. With the latter, the zone of mineralization moved slowly towards the implant surface. Implant sites prepared by the osteotome technique showed a pronounced signal in the whole compressed area already by the second day. In conclusion, the osteotome technique increases new bone formation and leads to an enhanced osseointegration of dental implants in trabecular bone. However, more experimental trials have to be carried out on higher mammals that show a metabolic rate of bone that is more comparable to humans.