Guided biopsy of osseous pathologies in the jaw bone using a 3D-printed,tooth-supported drilling template

Suspicious radiological findings in the jaw bone require histopathological examination for the confirmation of a diagnosis. As pathologies in this region are difficult to reach or are in close proximity to relevant anatomical structures, e.g. tooth roots or nerves, they often represent a challenge. Such factors may adversely affect the predictability of the surgical outcome of a biopsy of the osseous tissues. This technical note introduces a novel method for performing a digitally planned, guided biopsy. For this purpose, a cone beam computed tomography scan and an intraoral scan are superimposed using specific planning software. The resulting three-dimensionally printed, tooth-supported drilling template is designed for a trephine biopsy. It allows a precise, minimally invasive approach, with an exact three-dimensional determination of the biopsy location prior to surgery. The risk of devitalization of the neighbouring teeth or possible damage to the nerve structures can be minimized. Furthermore, a small access flap can be sufficient. In summary, the method of bone biopsy presented here allows high precision and greater predictability for biopsy sampling and is minimally invasive for the patient.     

Five-year survival rates for implants placed using digitally-designed static surgical guides: a systematic review

Digitally-designed static surgical guides provide an acceptable level of accuracy and predictability for the placement of dental implants. However, to our knowledge, few published studies have compared the long-term survival of implants placed in this way with those placed using other methods. A systematic search of electronic databases using a population, intervention, comparison, and outcome (PICO) framework was conducted of Medline and EMBASE, as well as grey literature and hand searches, to obtain all relevant work pertaining to the survival of dental implants placed by guided surgery. The studies were required to have at least 10 patients with a follow up of at least five years. A total of 621 titles were screened. Four studies met the inclusion criteria for quantitative analysis, and they all reported the exclusive use of Nobel Biocare implants and the NobelGuide system (Nobel Biocare Services). Cumulative survival rates ranged from 94.5% to 100% over five years. The survival rates of implants placed using digitally-designed static surgical guides are comparable to the estimated overall survival rate (95.6% over five years), despite the complex nature of the treatments done with guided surgery. Clinicians who do these operations should, however, have the experience and ability to revert to conventional freehand techniques if complications arise.     

Cone beam computed tomography findings in temporomandibular joint of chronic qat chewers: Dimensional and osteoarthritic changes

The social habit of chewing qat (also known as khat) is widely practised in East Africa and the Arabian Peninsula. It has been linked with various oro-facial conditions, including temporomandibular joint disorders (TMD). This cross-sectional, comparative study sought to investigate the effects of qat chewing on temporomandibular joint (TMJ), using cone beam computed tomography (CBCT). A total of 85 Yemeni males were included. The participants were divided into two groups: Qat chewers (QC; n = 41) and non-qat chewers (NQC; n = 44). Relevant data were obtained using a structured questionnaire and standardised clinical examination. Additionally, CBCT images of the TMJs were obtained, and then, osteoarthritic changes and TMJ dimensions were analysed. SPSS 21 was used for statistical analyses, with a significant level was set at 0.05. Compared to NQC, a significantly higher proportion of QC presented with clinical signs of TMDs. The qualitative CBCT findings revealed significantly higher osteoarthritic changes in QC than in NQC: osteophyte (51.2% vs 22.7%; P = .008), subcortical sclerosis (48.8% vs 27.3%; P = .047), articular surface flattening (46.3% vs 6.8%; P = .009) and subcortical cysts (43.9% vs 4.5%; P < .001). However, CBCT quantitative findings (condylar dimensions) did not show significant differences between the two groups. The chewing side of the QC group showed slightly more changes compared to the non-chewing side. The results demonstrate that qat chewing has detrimental effects on TMJ manifested mainly as osteoarthritic changes. Further large-scale studies are recommended.     

Evaluating the accuracy of resection planes in mandibular surgery using a preoperative,intraoperative, and postoperative approach

In mandibular surgery, three-dimensionally printed patient-specific cutting guides are used to translate the preoperative virtually planned resection planes to the operating room. This study was performed to determine whether cutting guides are positioned according to the virtual plan and to compare the intraoperative position of the cutting guide with the resection performed. Nine patients were included. The exact positions of the resection planes were planned virtually and a patient-specific cutting guide was designed and printed. After surgical placement of the cutting guide, intraoperative cone beam computed tomography (CBCT) was performed. Postoperative CT was used to obtain the final resection planes. Distances and yaw and pitch angles between the preoperative, intraoperative, and postoperative resection planes were calculated. Cutting guides were positioned on the mandible with millimetre accuracy. Anterior osteotomies were performed more accurately than posterior osteotomies (intraoperatively positioned and final resection planes differed by 1.2 ± 1.0 mm, 4.9 ± 6.6°, and 1.8 ± 1.5°, respectively, and by 2.2 ± 0.9 mm, 9.3 ± 9°, and 8.3 ± 6.5° respectively). Differences between intraoperatively planned and final resection planes imply a directional freedom of the saw through the saw slots. Since cutting guides are positioned with millimetre accuracy compared to the virtual plan, the design of the saw slots in the cutting guides needs improvement to allow more accurate resections.     

Anatomy of the accessory mental foramen in a Saudi subpopulation: A multicenter CBCT study

AimThe aim of this is to evaluate the prevalence and location of the accessory mental foramen (AMF) in a Saudi population using cone-beam computed tomography (CBCT).MethodologyCBCT data were retrieved from two dental facilities at two universities located in two different cities and filtered over a period of four years. The scans were aligned when the AMF was noticed, and then the size of both the AMF and mental foramen (MF), its location, and the distance from the AMF to the MF were recorded. The AMF measurements were compared between males and females and between the two sides of the mandible.ResultsIn total, 603 CBCT scans were investigated. The percentage of scans with an AMF was 9.95% (n = 60), and AMFs were almost equally distributed on both sides. Only four cases (0.66%) of a second AMF were detected among the scans. The MFs on both sides were significantly larger in males than in females (P > 0.05), but they showed no differences in the sizes of the AMFs. The AMFs were most commonly located inferior and posterior to the MF. The distance between the MF and AMF ranged from 2.32 to 5 mm.ConclusionsThe prevalence of the AMF in this Saudi population was 9.95%, and it was significantly more prevalent in males than in females. Its proximity to the MF makes it clinically important to conduct proper detailed planning prior to performing any procedure that might risk the vital structures.     

骨性Ⅲ类与Ⅰ类错患者基骨及牙弓宽度的比较研究

目的：评价骨性Ⅲ类错合与骨性I类个别正常合上下颌第一磨牙区基骨及牙弓宽度差异。方法：选取骨性Ⅲ类错合患者与骨性I类个别正常合样本各30例。测量CBCT数据中上颌骨颧弓点和下颌第一磨牙阻抗中心对应的颊侧骨皮质点间的距离作为基骨宽度；测量模型上下颌第一磨牙中央窝之间的距离作为牙弓宽度。使用SPSS 22.0独立样本t检验。结果：上颌基骨宽度Ⅲ类组（63.96±3.78mm）小于I类组（65.67±2.76mm）；下颌基骨宽度Ⅲ类组（62.26±3.12mm）大于I类组（60.29±3.15mm）；基骨宽度差为Ⅲ类组（2.31±2.41mm）小于I类组（5.38±1.24mm）。差异均有统计学意义（P<0.05）。Ⅲ类组与I类组上下颌牙弓宽度均无组间差异（P>0.05）。结论：骨性Ⅲ类患者存在上下颌基骨横向发育不调及上下颌磨牙的颊舌向代偿。     

数字化影像技术在牙周临床诊疗中的应用

 影像技术是牙周病和种植体周围病的重要辅助检查手段，随着数字化技术的发展，数字化影像技术不仅使牙周病和种植体周围病的检查和诊断越来越快捷、准确，而且在治疗计划的设计和疗效评价中扮演着越来越重要的角色。文章将对数字化影像技术在牙周临床诊治中的应用及进展进行简要介绍。