Patient-specific beta-tricalcium phosphate scaffold for customized alveolar ridge augmentation: a case report : Case Report: patient-specific β-TCP scaffold for alveolar ridge CBR

BACKGROUND

Beta-tricalcium phosphate (β-TCP) is a biocompatible ceramic material widely used in the field of oral regeneration. Due to its excellent biological and mechanical properties, it is increasingly utilized for alveolar ridge augmentation or guided bone regeneration (GBR). With recent advances in computer-aided design and manufacturing (CAD/CAM), β-TCP can now be used in the form of digitally designed patient-specific scaffolds for customized bone regeneration (CBR) of advanced defects in a two-stage implant therapy concept. In this case report following the CARE case report guidelines, we present a novel application of a patient-specific β-TCP scaffold in pre-implant mandibular alveolar ridge augmentation.

CASE PRESENTATION

A 63-year-old female patient with significant horizontal bone loss in the posterior mandible was treated with a custom β-TCP scaffold in the context of a two-stage backward-planned implant therapy. Cone-beam computed tomography nine months after augmentation showed successful integration of the scaffold into the surrounding bone, allowing implant placement. Follow-up until two years after initial surgery showed excellent oral and peri-implant health.

CONCLUSIONS

This case highlights the potential of patient-specific β-TCP scaffolds for alveolar ridge augmentation and their advantage over traditional techniques, including avoidance of xeno-, allo-, and autografts. The results provide encouraging evidence for their use in clinical practice. Patient-specific β-TCP scaffolds may be a promising alternative for clinicians seeking to provide their patients with safe, predictable, and effective alveolar ridge augmentation results in customized bone regeneration procedures.

Magnetic resonance imaging in dental implant surgery: a systematic review

PURPOSE

To comprehensively assess the existing literature regarding the rapidly evolving in vivo application of magnetic resonance imaging (MRI) for potential applications, benefits, and challenges in dental implant surgery.

METHODS

Electronic and manual searches were conducted in PubMed MEDLINE, EMBASE, Biosis, and Cochrane databases by two reviewers following the PICOS search strategy. This involved using medical subject headings (MeSH) terms, keywords, and their combinations.

RESULTS

Sixteen studies were included in this systematic review. Of the 16, nine studies focused on preoperative planning and follow-up phases, four evaluated image-guided implant surgery, while three examined artifact reduction techniques. The current literature highlights several MRI protocols that have recently investigated and evaluated the in vivo feasibility and accuracy, focusing on its potential to provide surgically relevant quantitative and qualitative parameters in the assessment of osseointegration, peri-implant soft tissues, surrounding anatomical structures, reduction of artifacts caused by dental implants, and geometric accuracy relevant to implant placement. Black Bone and MSVAT-SPACE MRI, acquired within a short time, demonstrate improved hard and soft tissue resolution and offer high sensitivity in detecting pathological changes, making them a valuable alternative in targeted cases where CBCT is insufficient. Given the data heterogeneity, a meta-analysis was not possible.

CONCLUSIONS

The results of this systematic review highlight the potential of dental MRI, within its indications and limitations, to provide perioperative surgically relevant parameters for accurate placement of dental implants.

Preoperative imaging in third molar surgery - A prospective comparison of X-ray-based and radiation-free magnetic resonance orthopantomography

This study aimed to compare preoperative data relevant to third molar surgery based on radiographic orthopantomography (OPG) and orthopantomogram-like MR images (MR-OPG), using five different MR protocols. X-ray-based OPG and OPG-like MRI reconstructions from DESS, SPACE-STIR, SPACE-SPAIR, T1-VIBE-Dixon, and UTE sequences were acquired in 11 patients undergoing third molar surgery, using a 15-channel mandibular coil. Qualitative (image quality, susceptibility to artifacts, positional relationship, contact/non-contact of the inferior alveolar nerve (IAN), relationship to maxillary sinus, IAN continuity, root morphology) and quantitative (tooth length, retromolar distance, distance to the IAN, and distance to the mandible margin) parameters of the maxillary and mandibular third molars were assessed regarding inter-reader agreement and quantitative discrepancies by three calibrated readers. Radiation-free MR-OPGs generated within clinically tolerable acquisition times, which exhibited high image quality and low susceptibility to artifacts, showed no significant differences compared with X-ray-based OPGs regarding the assessment of quantitative parameters. UTE MR-OPGs provided radiographic-like images and were best suited for assessing qualitative preoperative data (positional relationship, nerve contact/non-contact, and dental root morphology) relevant to third molar surgery. For continuous and focal nerve imaging, DESS MR-OPG was superior. MR-OPGs could represent a shift towards indication-specific and modality-oriented perioperative imaging in high-risk oral and maxillofacial surgery.

Radioactive nanosized colloids and indocyanine green identify the same sentinel lymph nodes in oral squamous cell carcinoma

PURPOSE

Near-infrared fluorescence imaging using indocyanine green (ICG) combined with radioactive markers has the potential to improve sentinel lymph-node (SLN) mapping in oral squamous cell carcinoma (OSCC). This study aimed to evaluate the ability of 99mTc and ICG in identifying the sentinel lymph nodes in patients with early stage OSCC.

METHODS

Data were collected prospectively, and a retrospective analysis of 15 patients with early stage OSCC and a cN0 neck was performed. All patients received peritumoral injection of 99mTc the day before surgery and ICG was administered intraoperatively. Intentionally, the application of the two different tracers were done by two different physicians with varying degrees of experience. The number of identified lymph nodes positive for 99mTc and ICG, the overlap or possible discrepancies of both methods, and the time until fluorescence signals of ICG were detected were noted.

RESULTS

In all patients, a 100% agreement in sentinel lymph-node identification was achieved, regardless of both the exact location of the peritumoral injection and the experience of the injecting surgeon. Time until ICG accumulation in the sentinel lymph node was consistently found to be between 1 and 3 min.

CONCLUSION

ICG constitutes a viable and useful addition to 99mTc for intraoperative sentinel lymph-node detection in this study.

Two-screw osteosynthesis of the mandibular condylar head with different screw materials: a finite element analysis

This study compared the biomechanical behavior of titanium, magnesium, and polylactic acid screws for two-screw osteosynthesis of mandibular condylar head fractures using finite element analysis. Von Mises stress distribution, fracture displacement, and fragment deformation were evaluated. Titanium screws performed the best in terms of carrying the highest load, resulting in the least fracture displacement and fragment deformation. Magnesium screws showed intermediate results, while PLA screws were found to be unsuitable with stress values exceeding their tensile strength. These findings suggest that magnesium alloys could be considered a suitable alternative to titanium screws in mandibular condylar head osteosynthesis.

MR-orthopantomography in operative dentistry and oral and maxillofacial surgery: a proof of concept study

This prospective study aimed to present, compare, and evaluate the suitability of five different magnetic resonance imaging (MRI) protocols (3D double-echo steady-state (DESS), 3D fast spin echo short-tau inversion recovery (SPACE-STIR), 3D fast spin echo spectral attenuated inversion recovery (SPACE-SPAIR), volumetric interpolated breath-hold examination (T1-VIBE-Dixon), and ultrashort echo time (UTE)) and for orthopantomogram (OPG)-like MRI reconstructions using a novel mandibular coil. Three readers assessed MR-OPGs of 21 volunteers regarding technical image quality (4, excellent; 0, severely reduced), susceptibility to artifacts (3, absence; 0, massive), and visualization of anatomical structures in the oral cavity and surrounding skeletal structures (4, fine details visible; 0, no structures visible). Average image quality was good (3.29 ± 0.83) for all MRI protocols, with UTE providing the best image quality (3.52 ± 0.62) and no to minor artifacts (2.56 ± 0.6). Full diagnostic interpretability of the osseous structures is best in VIBE-Dixon and UTE MR-OPGs. DESS provided excellent visualization of the finest details of the nervous tissue (3.95 ± 0.22). Intra-reader and inter-reader agreement between the readers was good to excellent for all protocols (ICCs 0.812-0.957). MR-OPGs provide indication-specific accurate imaging of the oral cavity and could contribute to the early detection of pathologies, staging, and radiological follow-up of oral and maxillofacial diseases.

Meeting Quality Metrics in Oral Squamous Cell Carcinoma Surgery: A Single-Center Experience

Patient-centered quality metrics have been proposed to evaluate and optimize hospital processes, aiming to improve patient outcomes. Furthermore, they can be used to objectively rate and compare the ability of health care providers to meet the needs of their patients. In patients with advanced resectable oral squamous cell carcinoma, optimal surgical treatment of the neck and timely initiation of both surgical and adjuvant therapy, when indicated, are crucial for recurrence-free and overall survival. This retrospective analysis included 160 patients who received primary resection of oral squamous cell carcinoma and concurrent neck dissection. It aimed to investigate how well quality metrics were met during a 6-year period in the department of oral and maxillofacial surgery at a university hospital. 93.1% of patients were seen in the specialist's office within 21 days after referral. Resection was classified as R0 in 94.4%. A lymph node yield ≥ 18 was achieved in 82.5%. The lymph node ratio was ≤6% in 43.3% of nodal-positive necks. Readmission and unplanned revision surgery were rare (6.9%). Adjuvant radiotherapy was started ≤ 6 weeks after surgery in 45.3%, and the indication was in accordance with international guidelines in all cases. Quality metrics are an effective tool for planning process optimization in a hospital. Moreover, nodal quality metrics such as lymph node yield and lymph node ratio could, after validation, complement existing and well-established prognostic parameters for patient-specific adaptation of adjuvant treatment plans.

Buccal bone thickness assessment for immediate anterior dental implant planning: A pilot study comparing cone-beam computed tomography and 3D double-echo steady-state MRI

PURPOSE

To evaluate image quality and diagnostic accuracy of buccal bone thickness assessment in maxillary and mandibular anterior region using cone-beam computed tomography (CBCT) and 3-dimensional double-echo steady-state (DESS) MRI for preoperative planning of immediate dental implants in healthy individuals.

METHODS

One hundred and twenty teeth in 10 volunteers were retrospectively evaluated for image quality and artifacts using Likert scale (4 = excellent to 0 = decreased). Buccal bone thickness was measured at three measurement points (M1 = 2 mm from the cementoenamel junction, M2 = middle of the root, and M3 = at the root apex) for each tooth in the maxillary (13-23) and the mandibular anterior region (33-43). Descriptive statistics and two-way ANOVA with Tukey's Post-hoc test were performed to evaluate the significant differences (α = 0.05) between both imaging modalities.

RESULTS

Image quality showed little to no artifacts and enabled confident diagnostic interpretation (CBCT (3.72 ± 0.46); MRI (3.65 ± 0.49)), with no significant differences between both imaging modalities (p > 0.05). Regarding the assessment of buccal bone thickness at M1-M3 for the teeth 13-23 and 33-43, no significant differences were noted (p > 0.05). MRI demonstrated slight, nonsignificant overestimation of thickness with the canines having mainly a thick buccal bone wall, where thin buccal wall was evident for the central incisors.

CONCLUSION

Black bone MRI sequences, such as 3D-DESS MRI, for immediate implant planning provided confidential diagnostic accuracy in bone thickness assessment without significant disadvantages compared to CBCT. Thus, the implementation of no-dose protocols for dental rehabilitation using an immediate loading approach seems promising and could further improve the treatment strategy for dental rehabilitation.

[A radiolucent rarity - primary intraosseous mucoepidermoid carcinoma of the posterior mandible: From radiographic incidental finding to molecular pathological diagnosis]

We report the case of a 64-year-old patient with incidental finding of a unilocular radiolucency in the posterior mandible on an apical radiograph. The biopsy (cystostomy) revealed the unusual finding of a primary intraosseous mucoepidermoid carcinoma; this is with 2‑4% of ectopic manifestations of this entity a rarity. Molecular pathological analysis with a specific panel (SalvGlandDx) and FISH provided diagnosis-confirming evidence of the specific CRTC1-MAML2 fusion. Box resection, prophylactic osteosynthesis using a patient-specific reconstruction plate, neck dissection, and local coverage using a Bichat flap were performed according to the interdisciplinary tumor board decision. With tumor-free lymph nodes and R0 resection, adjuvant therapy was not required. Clinical and imaging follow-up over 24 months showed no evidence of locoregional recurrence. The presented case report emphasizes the central role of private dental practices in the early detection of oral malignancies. These should always be considered in the differential diagnosis of cystic lesions.

Bilateral supernumerary maxillary fourth and fifth molars: A clinical case report and literature review

Supernumerary teeth that are present in the molar region may be evident based on crowding and impaction, but most cases are asymptomatic and discovered as incidental findings during routine radiological examinations. This article reports the case of a 29-year-old woman who presented with a severe feeling of pressure in the region of the maxillary third molars that had been increasing in intensity for weeks. A clinical examination revealed crowding of the maxillary anterior teeth despite the completion of orthodontic treatment and an erupted third molar with localized gingivitis in the second quadrant. A radiographic examination revealed bilateral supernumerary maxillary fourth and fifth molars, so cone-beam computed tomography was performed to locate the supernumerary teeth precisely for a preoperative diagnosis and comprehensive treatment planning. This report presents the radiological and surgical case management of a rare case of bilateral supernumerary molars and reviews the literature regarding epidemiology and treatment options.

Dental MRI of Oral Soft-Tissue Tumors—Optimized Use of Black Bone MRI Sequences and a 15-Channel Mandibular Coil

Soft-tissue lesions in the oral cavity, one of the most common sites for tumors and tumor-like lesions, can be challenging to diagnose and treat due to the wide spectrum from benign indolent to invasive malignant lesions. We report an abnormally large, rapidly growing hyperplastic lesion originating from the buccal mucosa in a 28-year-old male patient. Clinical examination revealed a well-circumscribed, smooth-surfaced, pinkish nodular lesion measuring 2.3 × 2 cm, which suggested the differential diagnosis of irritation fibroma, pyogenic granuloma, oral lipoma, and other benign or malignant neoplasms such as hemangioma, non-Hodgkin’s lymphoma, or metastases to the oral cavity. Dental MRI using a 15-channel mandibular coil was performed to improve perioperative radiological and surgical management, avoiding adverse intraoperative events and misdiagnosis of vascular malformations, especially hemangiomas. Black bone MRI protocols such as STIR (short-tau inversion recovery) and DESS (double-echo steady-state) were used for high-resolution radiation-free imaging. Radiologic findings supported the suspected diagnosis of an irritation fibroma and ruled out any further head and neck lesions, therefore complete surgical resection was performed. Histology confirmed the tentative diagnosis. This article evaluates the use of this novel technique for MR diagnosis in the perioperative management of soft-tissue tumors in oral and maxillofacial surgery.

Visualization of Inferior Alveolar and Lingual Nerve Pathology by 3D Double-Echo Steady-State MRI: Two Case Reports with Literature Review

Injury to the peripheral branches of the trigeminal nerve, particularly the lingual nerve (LN) and the inferior alveolar nerve (IAN), is a rare but serious complication that can occur during oral and maxillofacial surgery. Mandibular third molar surgery, one of the most common surgical procedures in dentistry, is most often associated with such a nerve injury. Proper preoperative radiologic assessment is hence key to avoiding neurosensory dysfunction. In addition to the well-established conventional X-ray-based imaging modalities, such as panoramic radiography and cone-beam computed tomography, radiation-free magnetic resonance imaging (MRI) with the recently introduced black-bone MRI sequences offers the possibility to simultaneously visualize osseous structures and neural tissue in the oral cavity with high spatial resolution and excellent soft-tissue contrast. Fortunately, most LN and IAN injuries recover spontaneously within six months. However, permanent damage may cause significant loss of quality of life for affected patients. Therefore, therapy should be initiated early in indicated cases, despite the inconsistency in the literature regarding the therapeutic time window. In this report, we present the visualization of two cases of nerve pathology using 3D double-echo steady-state MRI and evaluate evidence-based decision-making for iatrogenic nerve injury regarding a wait-and-see strategy, conservative drug treatment, or surgical re-intervention.

Two-versus three-screw osteosynthesis of the mandibular condylar head: A finite element analysis

Titanium screws are commonly used for osteosynthesis of mandibular condylar head fractures. Evidence suggests that the insertion of three screws may result in better fracture stability. Two screws only, on the other hand, could reduce adverse effects, mainly bone resorption. This study aimed to investigate the biomechanical differences in mandibular condylar head osteosynthesis with two versus three titanium screws using finite element analysis. A finite element model of the mandible with a right type P condylar head fracture fixed with two or three titanium screws was analyzed in ANSYS Mechanical. The geometry of the model assembly was constructed in ANSYS Spaceclaim. Biomechanical load boundary conditions were obtained from a validated musculoskeletal model in AnyBody Modeling System™. The preprocessing of the finite element model and mapping of the obtained boundary conditions was done in docq VIT. Fracture displacement, fragment deformation, von Mises stress distribution, and reaction forces within the screws were evaluated in ANSYS for three different loading scenarios. Finite element analysis showed similar results when comparing osteosynthesis with two versus three titanium screws for all three loading scenarios. Contralateral molar loading resulted in the highest stress on both the fracture and the screws with the maximum von Mises stress being found at the condylar neck. Stress concentration within the screws was found in the fracture gap and was higher in the lateral fragment. In all scenarios, maximum von Mises stress values were smaller when forces were distributed among three screws. However, stability was also adequate when two screws were used. Mandibular condylar head osteosynthesis with two titanium screws appears to provide sufficient fracture stability. Further clinical studies are needed to clarify the implications of these results.

ASA score and procedure type predict complications and costs in maxillofacial reconstructive surgery: a retrospective study using a hospital administrative database

BACKGROUND

Reconstruction of osseous and soft tissue defects after surgical resection of oral cavity cancers can be achieved by a single-stage procedure with a microvascular bone flap or by a two-step approach with a soft tissue flap and subsequent bone augmentation. The therapeutic approach should be selected based on the patient’s needs. Economic pressure requires preoperative risk assessment and estimation of the postoperative course. Flat-rate reimbursement systems via diagnosis-related groups with insufficient morbidity adjustments and financial sanction of medical complications might additionally cause false incentives in the choice of treatment.

OBJECTIVE

This study aimed to assess the influence of the type of flap chosen for maxillofacial reconstructive surgery on the total costs. Complication rates of different types of flap surgery and their prediction by a preoperative risk assessment tool (American Society of Anesthesiologists [ASA] score) were determined. Overall, the fairness of the current reimbursement system was rated.

METHODS

Patient characteristics, clinical data, and data on total costs and reimbursement of patients aged 18 years and older having undergone maxillofacial reconstructive flap surgery at the University Hospital of Zurich (Switzerland) between 2012 and 2014 were analysed. The preoperative risk was classified by the ASA score. Complications were graded according to the Clavien-Dindo classification system and the comprehensive complication index (CCI). Statistical analysis included Spearman and Pearson rank correlation, Kruskal-Wallis and Mann-Whitney nonparametric tests, and linear regression analysis.

RESULTS

129 patients were included in this study. Soft tissue flaps were performed in 82 patients, of which 56 were radial forearm flaps (43.4%), bone flaps in 41 patients, of which 32 were fibula flaps (24.8%), and combined flaps in 6 patients (4.7%). Patients with fibula flaps showed a significantly higher CCI and higher total costs. Higher preoperative ASA scores were significantly associated with increased length of stay, total costs and complications. Both the ASA score and reconstruction with a radial forearm flap were significant predictors of complications and total costs. Total median costs for radial forearm flaps were CHF 50,560 (reimbursement: CHF 60,851; difference: CHF 10,291) and for fibula flaps CHF 66,982 (reimbursement: CHF 58,218; difference: CHF −8,764).

CONCLUSION

The ASA score allows a reliable preoperative assessment of patient outcomes and financial burden in maxillofacial reconstructive flap surgery. The type of flap reconstruction significantly influences complications and ultimately total costs. The current reimbursement system via diagnosis-related groups (DRGs) does not take sufficient account of this fact. Adaptations are therefore needed to prevent misplaced incentives to the detriment of patients.