Dental invagination is an abnormality of the crown or root development induced during tooth germ development when the enamel-forming apparatus or epithelial root sheath overpopulates and folds into the papilla. In severe cases, the invaginated channels are connected to the pulp and periodontal tissues, often causing endodontic and periapical diseases. The complex anatomical pattern of this disease adds difficulty in its preoperative diagnosis and clinical operation. In this paper, we report a case of non-surgical treatment assisted by cone beam CT and microscopy for maxillary lateral incisor double dens invaginatus type Ⅲ (Ⅲa and Ⅲb) with apical periapical infection. After 1-year follow-up, the affected tooth was asymptomatic and the periapical lesion was significantly reduced.
牙内陷是牙胚发育期成釉器或上皮根鞘过度增殖，卷叠入牙乳头引起的牙冠或牙根发育异常。严重内陷的患牙内陷通道与牙髓和牙周组织相通，常引起牙髓病和根尖周病，其复杂的解剖形态为术前诊断和临床操作增加了难度。本文报道了1例上颌侧切牙Ⅲ型双牙内陷伴根尖周炎的病例，在锥形束CT和显微镜辅助下行非手术治疗，随访1年，患牙无症状，根尖周病变明显缩小。.

OBJECTIVE: This retrospective study explored the incidence of independent distal-lingual root (DLR) in mandibular first molars and the morphologic features of distal furcations through cone beam computed tomography (CBCT) in Beijing population.
METHODS: A total of 401 CBCT images of both mandibular first molars existed were included. The sex of the patients, the incidence of DLR, the distal root trunk length (DRT), the locations of distal furcation entrance (DFE), and the separation angle of distal furcation (ADF) were recorded.
RESULTS: The incidence rates of DLR were 33.2% on the subject level and 26.8% on the tooth level. The incidence of DLR was not different between genders but was higher on the right sides. The DRT values were 4.15 mm±1.02 mm. The ADF was 65.56°±11.56°. The DFE was located lingually, and 97.2% DFE was located more apically than buccal/lingual furcations.
CONCLUSIONS: A high incidence of DLR was found in the Beijing population. The DRT was longer than buccal and lingual sites. The DFE was located lingually with a wide separation. Understanding the morphological features of distal furcation can help clinicians to make proper treatment plans.
目的: 通过对锥形束CT（CBCT）图像进行回顾性研究，探究北京地区人群下颌第一磨牙独立远中舌根的发生率以及远中根分叉区的形态特征，为牙周诊疗提供依据。方法: 选取有双侧下颌第一磨牙存在的CBCT资料共401例，记录患者性别、是否存在独立远中舌根，统计其发生率。在存在远中根分叉的下颌第一磨牙CBCT图像中，测量并记录远中根分叉的根柱长度、远中根分叉开口的位置以及远中根分叉开口的角度。结果: 在401例CBCT图像资料中，下颌第一磨牙独立远中舌根的发生率在个体水平为33.2%，牙水平为26.8%。不同性别发生率无差异，右侧发生率更高。远中根柱长度为4.15 mm±1.02 mm，位置均偏舌侧，远中根分叉开口的角度为65.56°±11.56°，97.2%的远中根分叉开口较颊舌侧根分叉开口更偏根方。结论: 北京地区人群有较高的下颌第一磨牙远中舌根的发生率。下颌第一磨牙的远中根柱较颊舌侧根柱更长，根分叉开口位置偏舌侧，分叉角度较大。了解远中根分叉的形态有利于临床医师制定完善的诊疗方案。.

OBJECTIVE: This study aimed to assess hard and soft tissue contour changes following micro crestal flap-alveolar ridge preservation (MCF-ARP) and natural healing (NH) in periodontally compromised molar extraction sites and to analyse the feasibility and need for bone augmentation during implant therapy.
METHODS: Fifty-six patients with 70 sites were randomized into two groups at the site level (35 sites from 31 patients in the test group and 35 sites from 29 patients in the control group). Among whom, four patients contributed one tooth to the control group and one tooth to the test group. Hard tissue indicators were measured using cone beam computed tomography performed before tooth extraction and 6 months after surgery. Soft tissue contour changes were assessed using intraoral scanning performed before and immediately after surgery and also 2 weeks and 1, 3 and 6 months after surgery.
RESULTS: Six months after surgery, the MCF-ARP group showed less resorption in buccal bone height (p = .032) and greater augmentation in central bone height (p = .001) and ridge width (p = .009). The mean, vertical and horizontal collapse of buccal soft tissue contour in the MCF-ARP group were 0.95 mm (p = .010), 0.61 mm (p = .019) and 0.56 mm (p = .013) less than that in the NH group, respectively. There were significantly (p = .007) fewer sites in the MCF-ARP group than in the NH group (0% vs. 26.7%) for staged bone augmentation and more sites that could be treated with simple implant procedure in the MCF-ARP group than in the NH group (71.9% vs. 56.6%).
CONCLUSIONS: Compared with NH, MCF-ARP reduced bone resorption in periodontally compromised molar extraction sites and maintained the buccal soft tissue contour. MCF-ARP reduces the need for complex bone augmentation procedures in implant therapy.
BACKGROUND: Chinese Clinical Trial Register (ChiCTR) ChiCTR2200056335. Registered on 4 February 2022, Version 1.0.

OBJECTIVE: We propose a dual-domain cone beam computed tomography (CBCT) reconstruction framework DualCBR-Net based on improved differentiable domain transform for cone-angle artifact correction.
METHODS: The proposed CBCT dual-domain reconstruction framework DualCBR-Net consists of 3 individual modules: projection preprocessing, differentiable domain transform, and image post-processing. The projection preprocessing module first extends the original projection data in the row direction to ensure full coverage of the scanned object by X-ray. The differentiable domain transform introduces the FDK reconstruction and forward projection operators to complete the forward and gradient backpropagation processes, where the geometric parameters correspond to the extended data dimension to provide crucial prior information in the forward pass of the network and ensure the accuracy in the gradient backpropagation, thus enabling precise learning of cone-beam region data. The image post-processing module further fine-tunes the domain-transformed image to remove residual artifacts and noises.
RESULTS: The results of validation experiments conducted on Mayo\'s public chest dataset showed that the proposed DualCBR-Net framework was superior to other comparison methods in terms of artifact removal and structural detail preservation. Compared with the latest methods, the DualCBR-Net framework improved the PSNR and SSIM by 0.6479 and 0.0074, respectively.
CONCLUSIONS: The proposed DualCBR-Net framework for cone-angle artifact correction allows effective joint training of the CBCT dual-domain network and is especially effective for large cone-angle region.

Objective:To study the clinical anatomy of the sphenopalatine foramina by dissecting the sphenopalatine foramina during Vidian nerve branch neurotomy. The anatomy and CBCT images of sphenopalatine foramen were analyzed to facilitate the navigational of clinical operation using CBCT images. Methods:From October 2017 to September 2023, 84 cases（168 sides） of Vidian nerve branch neurotomy in our department were collected. The clinical summary was made according to the anatomy of sphenopalatine foramen during the operation. Preoperative CBCT imaging findings of the sphenopalatine foramina were also studied. Results:The clinical anatomy of sphenopalatine foramen could be divided into four types: middle meatus type（1.19%）, trans-meatus type（62.29%）, superior meatus type（33.33%） and double foramen type（1.19%）. The incidence of ethmoidal ridge was 98.81%. The distance from sphenopalatine foramina to posterior nasal canal were（14.63±2.66） mm to left and（14.65±2.63） mm to right, The position Angle ∠a of lower margin of sphenopalatine foramina were（62.36±10.05）° to left and（61.51±11.82）° to right, respectively. Axial CT images can be used to divide the sphenopalatine foramen into five levels: the upper edge of the sphenopalatine foramen level, the Vidian nerve level, the basal plate interaction level, the lower edge of the sphenopalatine foramen level and the pterygopalatine canal level. The agreement between endoscopic anatomy of sphenopalatine foramen and imaging navigation was 100%. Conclusion:The sphenopalatine foramina exhibit various anatomical types. The preoperative navigational CBCT reading can effectively identify the type of sphenopalatine foramina, guide the choice of surgical method, and help avoid serious complications. This has significant clinical application value.
目的：通过在翼管神经分支切断术术中解剖蝶腭孔，探讨蝶腭孔的临床解剖。再将解剖与蝶腭孔锥形束CT（cone beam computed tomography，CBCT）的影像结合分析，以实现通过蝶腭孔CBCT影像导航临床手术。 方法：收集2017年10月至2023年9月行翼管神经分支切断术患者84例（168侧），根据术中蝶腭孔的解剖进行临床总结，同时提取患者术前鼻窦CBCT研究蝶腭孔的影像学表现。 结果：蝶腭孔临床解剖可分为4中类型，中鼻道型占1.19%，跨鼻道型占62.29%，上鼻道型占33.33%，双孔型占1.19%。筛嵴出现率为98.81%。蝶腭孔-鼻后孔距离（SP）和蝶腭孔下缘位角（∠a）分别为左侧（14.63±2.66） mm、右侧（14.65±2.63） mm和左侧（62.36±10.05）°、右侧（61.51±11.82）°。轴位CT影像可将蝶腭孔层面分为5个层面：蝶腭孔上缘层面，翼管神经层面，基板交互层面，蝶腭孔下缘层面以及翼腭管层面。蝶腭孔内镜解剖与影像学导航契合度为100%。 结论：蝶腭孔具有多种解剖类型，术前导航般蝶腭孔CBCT阅片可有效的了解蝶腭孔的解剖，为选择手术方式及避免严重并发症发生提供参考，临床有一定应用价值。.

BACKGROUND: The authors retrospectively studied the relationship between the morphology and position of the articular disc in magnetic resonance imaging (MRI) and the morphology and position of the condyle in cone beam computed tomography (CBCT), with the purpose for providing reference for clinical diagnosis and treatment of temporomandibular disorders (TMD).
METHODS: Patients with both CBCT and MRI imaging data were studied retrospectively, excluding TMJ tumour, fracture, severe condylar morphological abnormalities, non-intercuspal position, and poor quality images. A total of 744 temporomandibular joints (TMJs) from 372 patients were included, with the mean age of 25.94±11.04Y (75 males and 297 females). T2-weighted image (T2WI) of MRI imagings were used to evaluate disc morphology and disc displacement, while CBCT was obtained to evaluate the condylar bone and sagittal condylar position. Data were analysed by Pearson Chi square test and Spearman correlation coefficient.
RESULTS: THE DISTRIBUTION OF 744 TMJS IS AS FOLLOWS: 1) DISC MORPHOLOGY: contracture (37.1 %) > biconcave (32.9 %) > irregular (18.5 %) > lengthened (11.4 %); 2) disc position: ADDWoR (48.3 %) > NA (26.9 %) > ADDWR (21.6 %) > PDDWR (2.8 %) > PDDWoR (0.4 %); 3) condylar position: concentric (43.7 %) > posterior (37.6 %) > anterior (18.7 %); 4) condylar bone: normal (63.4 %)> abnormal (36.6 %). There were significant differences in the distribution of disc morphology and disc position between the sex (P < 0.05). There were significant differences in the distribution of disc position and condylar morphology amongst the age groups (P < 0.05). There were significant differences in the distribution of disc position, condylar position and condylar morphology amongst disc morphology (P < 0.05), and there were positive correlation between disc position(r = 0.703, P = 0.000), the score of condyle (r = 0.478, P = 0.000) and disc morphology respectively. There were significant differences in the distribution of disc position and condylar position amongst condylar morphology (P < 0.05). There was a positive correlation between disc position and condyle morphology (r = 0.413, P = 0.000), and a negative correlation between condyle position and condyle morphology (r=-0.152, P = 0.000). There were significant differences in the distribution of disc position amongst condylar position (P < 0.05), but there was no linear correlation (P = 0.159).
CONCLUSIONS: The mutual distribution of disc morphology, disc position, condylar morphology and condylar position was statistically significant. Disc displacement did not necessarily lead to condylar bone changes, but 92.7 % TMJs with condylar bone abnormalities had disc displacement.
BACKGROUND: This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics committee (LCYJ2022014).

The canalis sinuosus, a canal containing the anterior superior alveolar nerve bundle, originates from the infraorbital canal and extends along the maxillary sinus and nasal cavity edges to the anterior maxilla. It was once regarded as an anatomical variation. However, with the widespread application of cone beam computed tomography (CBCT), the detection rate of canalis sinuosus in the population has increased. The canalis sinuosus exhibits diverse courses, branching into multiple accessory canals and terminating at the nasal floor or the anterior tooth region, with the majority traversing the palatal side of the central incisor. The anterior superior alveolar nerve bundle within the canalis sinuosus not only innervates and nourishes the maxillary anterior teeth, their corresponding soft tissues, and the maxillary sinus mucosa, but also relates to the nasal septum, lateral nasal wall, and parts of the palatal mucosa. To minimize surgical complications, implantologists need to investigate strategies for preventing and treating canalis sinuosus injuries. Preoperatively, implantologists should use CBCT to identify the canalis sinuosus and virtually design implant placement at a distance of more than 2 mm from the canalis sinuosus. Intraoperatively, implantologists should assess bleeding and patient comfort, complemented by precision surgical techniques such as the use of implant surgical guide plates. Postoperatively, CBCT can be employed to examine the relationship between the implant and the canalis sinuosus, and treatment of canalis sinuosus injuries can be tailored based on the patient\'s symptoms. This review summarizes the detection of canalis sinuosus in the population, its anatomical characteristics, and its physiological functions in the anterior maxilla, and discusses strategies for effectively avoiding canalis sinuosus injuries during implant surgery, thereby enhancing implantologists\' awareness and providing references for clinical decision-making.
窦管是一种包含上牙槽前神经束的管道，起自眶下管，沿上颌窦和鼻腔边缘延伸到上颌骨前部。窦管曾被认为是一种解剖变异。随着锥形束计算机体层摄影技术（CBCT）的广泛使用，人群中窦管检出增多。窦管在上颌骨前部走行较为多样，可发出多个副管，终止在鼻底或上前牙区，其中走行于中切牙腭侧居多。窦管中走行的上牙槽前神经束不仅支配上颌前牙及其相应软组织和上颌窦黏膜并提供营养支持，还涉及鼻中隔与鼻侧壁及部分腭部黏膜。为减少手术并发症，种植医师需要研究窦管损伤的防治策略。如术前使用CBCT识别窦管并通过虚拟手术的方式设计种植体距离窦管2 mm以上；术中评估患者的出血情况及关注患者感受并辅以数字化种植术导板等精准手术方式；术后通过CBCT检查种植体与窦管的关系并根据患者感受治疗窦管损伤。本文通过总结窦管在人群中的检出情况、分析窦管解剖结构特点以及窦管在上颌骨前部所发挥的生理功能，探讨在种植术中有效回避窦管损伤的策略，以期提高种植医师的认识，为临床决策提供参考。.

BACKGROUND: Often there is the need of moving endodontically treated teeth. Orthodontic movement may have no effect on the prognosis of teeth with root canal treatment (RCT). To verify this subject, we evaluated the effect of orthodontic movement on the prognosis of RCT teeth using cone-beam computed tomography (CBCT) and further explored the influence of orthodontic movement on the prognosis of RCT teeth with and without apical periodontitis (AP).
METHODS: This retrospective study was conducted by evaluating 169 RCT teeth of 100 patients who had undergone fixed orthodontic treatment. AP was assessed and classified using the CBCT periapical index. Univariate analysis of RCT outcome was performed for the total RCT group, RCT without AP group and RCT with AP group. Multivariate logistic regression was performed for the total RCT group and RCT without AP group, respectively, but not for the RCT with AP group. Variables related to the prognosis of RCT were included, such as age, gender, tooth position, RCT quality, coronal restoration quality, periodontal condition, orthodontic traction distance, and orthodontic rotation angle.
RESULTS: The orthodontic traction distance and rotation angle were not significantly correlated to the RCT outcomes, regardless of the presence of AP. Among the total RCT group, teeth with unqualified RCT (odds ratio = 3.42, P = .004) and inadequate coronal restoration (odds ratio = 4.40, P = .031) had a lower success rate. Of the 97 RCT teeth without AP, unqualified RCT was a risk factor for treatment failure (odds ratio = 3.55, P = .041). Of the 72 RCT teeth with AP, the univariate analysis showed that RCT quality were significantly related to the outcome (P = .042).
CONCLUSIONS: Orthodontic movement had no effect on the prognosis of RCT teeth regardless of the presence of AP.

The root of late-dental-age labial inversely impacted maxillary central incisors (LIIMCIs) typically develops to severe dilacerated morphology. Therefore, reliable posttreatment periodontal estimates of orthodontic treatment prognosis would be critical to the treatment value of impacted incisors. This study aims to analyze further changes in dimensions of the alveolar bone following the closed-eruption treatment of late-dental-age dilacerated LIIMCIs. Cone beam computed tomography (CBCT) scanning data of 16 patients with unilateral dilacerated late-dental-age LIIMCIs were collected, including the pretreatment (T1) and at the 2.23 ± 0.78 years follow-up stage (T2) respectively. Patients underwent closed-eruption treatments to bring the impacted incisor into the dental arch. Dolphin imaging software was used to measure alveolar bone height labially, palatally, and proximally to the site at T1 and T2, as well as alveolar bone thicknesses at 0, 2, 4, 6 and 8 mm below the initial measurement plane (IMP). The alveolar bone heights on the impacted and contralateral sides increased from T1 to T2 (p < 0.05). Alveolar bone growth on both sides had no significant difference. In T2, the mean values of labial and distal alveolar heights on the contralateral sides were greater than on the impacted sides (p < 0.05). The mean values of total alveolar bone thicknesses on the impacted sides in T1 were significantly smaller than those on the contralateral sides in IMP-0, 2, 4, 6, 8 (p < 0.05). The total thicknesses on the impacted sides in T2 increased and were significantly greater than on the contralateral sides (p < 0.05), except for the thickness in IMP-0. The closed-eruption treatment of dilacerated late-dental-age LIIMCIs results in no significant changes to alveolar bone height, except on the labial and distal sides, with increased alveolar bone thickness, suggesting that this approach may be viable first choice therapy for non-extraction orthodontic cases.

BACKGROUND: The aim of the study was to establish a weighted comprehensive evaluation model (WCEM) of image registration for cone-beam computed tomography (CBCT) guided lung cancer radiotherapy that considers the geometric accuracy of gross target volume (GTV) and organs at risk (OARs), and assess the registration accuracy of different image registration methods to provide clinical references.
METHODS: The planning CT and CBCT images of 20 lung cancer patients were registered using diverse algorithms (bony and grayscale) and regions of interest (target, ipsilateral, and body). We compared the coverage ratio (CR) of the planning target volume (PTVCT) to GTVCBCT, as well as the dice similarity coefficient (DSC) of the GTV and OARs, considering the treatment position across various registration methods. Furthermore, we developed a mathematical model to assess registration results comprehensively. This model was evaluated and validated using CRFs across four automatic registration methods.
RESULTS: The grayscale registration method, coupled with the registration of the ipsilateral structure, exhibited the highest level of automatic registration accuracy, the DSC were 0.87 ± 0.09 (GTV), 0.71 ± 0.09 (esophagus), 0.74 ± 0.09 (spinal cord), and 0.91 ± 0.05 (heart), respectively. Our proposed WCEM proved to be both practical and effective. The results clearly indicated that the grayscale registration method, when applied to the ipsilateral structure, achieved the highest CRF score. The average CRF scores, excellent rates, good rate and qualification rates were 58 ± 26, 40%, 75%, and 85%, respectively.
CONCLUSIONS: This study successfully developed a clinically relevant weighted evaluation model for CBCT-guided lung cancer radiotherapy. Validation confirmed the grayscale method\'s optimal performance in ipsilateral structure registration.