Intraoral ultrasonography image registration for evaluation of partial edentulous ridge: A methodology and validation study.

OBJECTIVES: Ultrasound (US) reveals details for diagnosing soft- and hard-tissue dimensions around teeth, implants, and the edentulous ridge, not seen in 2D radiographs. Co-registering free-hand US scans with other 3D modalities presents reliability challenges. This study first aims to develop and validate a registration method to longitudinally reproduce US images of the jawbone on a simulator. In addition, it also evaluates the degree of the anatomical match in humans between US images acquired by the proposed registration method and the commonly used freehand acquisitions in comparison to cone beam computed tomography (CBCT) and intra-oral optical scan (IOS), used as references. METHODS: A previously introduced ultrasound phantom was employed as a CBCT-US hybrid, suitable for training and technique development of US guides in edentulous ridges. After establishing feasibility in the phantom, the methodology was validated in a cohort of 24 human subjects (26 cases). Soft tissues were delineated on US and IOS, and hard tissues on US and CBCT. US accuracy and repeatability from both guided and freehand scans (non-guided) was assessed as the average distance between US and the references. RESULTS: Guided US images resembled the references more closely than freehand (non-guided) scans. Notably, delineation of soft and hard tissues was significantly more accurate when employing guides. In the phantom, guided scans exhibited an absolute mean deviation of 81.8 µm for gingiva and 90.4 µm for bone, whereas non-guided scans showed deviations of 150.4 µm and 177.2 µm, respectively. Similarly, in vivo, guided US outperformed non-guided US, with gingiva deviations of 125 µm and 196 µm, and bone deviations of 354 µm and 554 µm, respectively. CONCLUSIONS: By using a registration method, guided US scans improved repeatability and accuracy of mapping hard and soft tissue of the edentulous ridge when compared to non-guided scans. CLINICAL RELEVANCE: This guided US imaging method could lay the foundation for longitudinal evaluation of tissue behavior and dimensional changes with improved accuracy.

Oral Frenum Composition and Clinical Implications in Bone Regeneration: A Review.

Successful bone augmentation relies on primary wound closure. The labial frenum is a soft tissue that connects the lip to the alveolar mucosa or gingiva. However, the frenum may exert biomechanical forces to the wound edge, causing wound instability. The aim of this study is to review the frenum composition and classifications and to understand the significance of the frenum in wound stability upon bone regeneration. Together with a manual search, an electronic search was conducted through three online databases on studies published until September 2022. A total of 300 articles were identified, and 9 studies were included in this review. Two of the included studies discovered that 35% to 37.5% of the labial frenum had muscle fibers. Other studies showed that the labial frenum was mainly composed of connective tissue with elastic fibers. There are two widely used classifications for the frenum based on its morphology and attachment position. No studies specifically evaluated the impact of the frenum on bone regeneration, but the frenum location intercorrelated with the amount of keratinized tissue, which could influence wound stability. A modified frenum classification for the edentulous ridge and a decision diagram to manage the frenum is proposed for research and evidence-based practice.

Relationship of Maxillary Sinus Volume and Nasal Septum Deviation: A Cone Beam Computed Tomography Study.

The present study was designed to test the hypothesis that there would be a correlation between nasal septum deviation (NSD) and a decreased maxillary sinus volume (MSV) in a Colombian population, using Cone Beam Computed Tomography (CBCT); other sinusal anatomical structures found during the reading were described and analyzed. A retrospective analysis of 537 CBCT scans of adult patients taken between January 2014 and January 2017 included measuring the maxillary sinus diameter in the vertical, horizontal, and sagittal planes. NSD was quantified and related to MSV using the same field of view (FOV). The volume of the right and left maxillary sinuses showed a median and interquartile range (IQR) of 8.18 mm3 (IQR: 6.2-10.33) and 8.3 mm3 (IQR: 6.4-10.36). Statistically significant differences were observed between sex and right and left MSV (p = 0.000), with higher MSV in men. The presence of NSD was observed in 96.81% of the sample and was evaluated in degrees, observing a median of 11° (IQR: 7-16) where 40% of the sample had moderate angles (9-15°). There was no correlation between NSD and a decreased MSV in the population studied. Detailed CBCT analysis with a large FOV is crucial for the analysis of anatomical structures before performing surgical procedures that involve the MS as a preventive diagnostic and therapeutic step for appropriate treatment.

A conceptual review on reconstructive peri-implantitis therapy: Challenges and opportunities.

OBJECTIVES: The current strategies to reconstruct lost peri-implant tissues due to the disease have been largely unpredictable. The aim of this conceptual review is to discuss relevant biological and biomechanical challenges of applying reconstructive means to treat peri-implantitis. Additionally, opportunities to improve treatment predictability are presented. MATERIAL AND METHODS: A narrative review was conducted to fulfill the aim. RESULTS: The four interrelated negative conditions hampering effective reconstruction are: inferior tissue perfusion, unfavorable bone topography, ineffective surface treatment, and unstable wound. First, peri-implant tissues resemble scars with reduced cellularity and vascularity, coupled with the absence of the periodontal ligament plexuses and the avascular implant and biomaterials, maintaining primary closure is a challenge, which is critical for regeneration. Second, defect morphology and bone topography surrounding implants determine the reconstructive potential. Unfortunately, noncontained defects are frequently encountered, with a combination of suprabony (horizontal bone loss) and infrabony (vertical usually involving circumferential bone loss) defects. Third, current attempts for implant surface decontamination are insufficient due to inaccessible macrostructure and rough surfaces in the micro-scale. Histologic evaluation has shown bacteria aggregation and calcified deposits around implants. Lastly, wound stability is difficult to achieve due to inherent soft tissue biomechanical quality and quantity deficiencies and mobile bone particulates. Opportunities to tackle the abovementioned challenges include the use of novel imaging technologies, such as high-frequency dental ultrasound and laser speckle imaging to evaluate tissue perfusion, soft tissue quality/quantity, and bone topography pre-surgically. The use of the operating microscope could allow better visualization and removal of etiologic factors. Strategies to improve soft tissue quality may include preoperative control of soft tissue inflammation and the potential use of biologics. Methods such as fixation to stabilize the biomaterials could be beneficial. CONCLUSIONS: A more nuanced understanding of the current challenges and opportunities can lead to more effective preoperative and postoperative care protocols, ultimately improving the success rate of reconstructive procedures.

Overview of Ultrasound in Dentistry for Advancing Research Methodology and Patient Care Quality with Emphasis on Periodontal/Peri-implant Applications.

BACKGROUND: Ultrasound is a non-invasive, cross-sectional imaging technique emerging in dentistry. It is an adjunct tool for diagnosing pathologies in the oral cavity that overcomes some limitations of current methodologies, including direct clinical examination, 2D radiographs, and cone beam computerized tomography. Increasing demand for soft tissue imaging has led to continuous improvements on transducer miniaturization and spatial resolution. The aims of this study are (1) to create a comprehensive overview of the current literature of ultrasonic imaging relating to dentistry, and (2) to provide a view onto investigations with immediate, intermediate, and long-term impact in periodontology and implantology. METHODS: A rapid literature review was performed using two broad searches conducted in the PubMed database, yielding 576 and 757 citations, respectively. A rating was established within a citation software (EndNote) using a 5-star classification. The broad search with 757 citations allowed for high sensitivity whereas the subsequent rating added specificity. RESULTS: A critical review of the clinical applications of ultrasound in dentistry was provided with a focus on applications in periodontology and implantology. The role of ultrasound as a developing dental diagnostic tool was reviewed. Specific uses such as soft and hard tissue imaging, longitudinal monitoring, as well as anatomic and physiological evaluation were discussed. CONCLUSIONS: Future efforts should be directed towards the transition of ultrasonography from a research tool to a clinical tool. Moreover, a dedicated effort is needed to introduce ultrasonic imaging to dental education and the dental community to ultimately improve the quality of patient care.