Three-dimensional printing of the human lung pleural cavity model for PDT malignant mesothelioma.

OBJECTIVE: The primary aim was to investigate emerging 3D printing and optical acquisition technologies to refine and enhance photodynamic therapy (PDT) dosimetry in the management of malignant pleural mesothelioma (MPM). MATERIALS AND METHODS: A rigorous digital reconstruction of the pleural lung cavity was conducted utilizing 3D printing and optical scanning methodologies. These reconstructions were systematically assessed against CT-derived data to ascertain their accuracy in representing critical anatomic features and post-resection topographical variations. RESULTS: The resulting reconstructions excelled in their anatomical precision, proving instrumental translation for precise dosimetry calculations for PDT. Validation against CT data confirmed the utility of these models not only for enhancing therapeutic planning but also as critical tools for educational and calibration purposes. CONCLUSION: The research outlined a successful protocol for the precise calculation of light distribution within the complex environment of the pleural cavity, marking a substantive advance in the application of PDT for MPM. This work holds significant promise for individualizing patient care, minimizing collateral radiation exposure, and improving the overall efficiency of MPM treatments.

A novel investigational preclinical model to assess fluence rate for dental oral craniofacial tissues.

OBJECTIVE: Photodynamic Therapy (PDT) and Photobiomodulation (PBM) are recognized for their potential in treating head and neck conditions. The heterogeneity of human tissue optical properties presents a challenge for effective dosimetry. The porcine mandible cadaver serves as an excellent model and has several similarities to human tissues of the dental oral craniofacial complex. This study aims to validate a novel modeling system that will help refine PDT and PBM dosimetry for the head and neck region. METHODS AND MATERIALS: Light transmission was analyzed through several tissue combinations at distances of 2 mm to 10 mm. Maximum light fluence rates (mW/cm2) were compared across tissue types to reveal the effects of tissue heterogeneity. RESULTS: The study revealed that light fluence is affected by tissue composition, with dentin/enamel showing reduced transmission and soft tissue regions exhibiting elevated values. The porcine model has proven to be efficient in mimicking human tissue responses to light, enabling the potential to optimize future protocols. CONCLUSION: The porcine mandible cadaver is a novel model to understand the complex interactions between light and tissue. This study provides a foundation for future investigations into dosimetry optimization for PDT and PBM.

Clinical PDT dose dosimetry for pleural Photofrin-mediated photodynamic therapy.

Significance: Photodynamic therapy (PDT) is an established cancer treatment utilizing light-activated photosensitizers (PS). Effective treatment hinges on the PDT dose-dependent on PS concentration and light fluence-delivered over time. We introduce an innovative eight-channel PDT dose dosimetry system capable of concurrently measuring light fluence and PS concentration during treatment. Aim: We aim to develop and evaluate an eight-channel PDT dose dosimetry system for simultaneous measurement of light fluence and PS concentration. By addressing uncertainties due to tissue variations, the system enhances accurate PDT dosimetry for improved treatment outcomes. Approach: The study positions eight isotropic detectors strategically within the pleural cavity before PDT. These detectors are linked to bifurcated fibers, distributing signals to both a photodiode and a spectrometer. Calibration techniques are applied to counter tissue-related variations and improve measurement accuracy. The fluorescence signal is normalized using the measured light fluence, compensating for variations in tissue properties. Measurements were taken in 78 sites in the pleural cavities of 20 patients. Results: Observations reveal minimal Photofrin concentration variation during PDT at each site, juxtaposed with significant intra- and inter-patient heterogeneities. Across 78 treated sites in 20 patients, the average Photofrin concentration for all 78 sites is 4.98 µM, with a median concentration of 4.47 µM. The average PDT dose for all 78 sites is 493.17 µMJ/cm2, with a median dose of 442.79 µMJ/cm2. A significant variation in PDT doses is observed, with a maximum difference of 3.1 times among all sites within one patient and a maximum difference of 9.8 times across all patients. Conclusions: The introduced eight-channel PDT dose dosimetry system serves as a valuable real-time monitoring tool for light fluence and PS concentration during PDT. Its ability to mitigate uncertainties arising from tissue properties enhances dosimetry accuracy, thus optimizing treatment outcomes and bolstering the effectiveness of PDT in cancer therapy.

Maintaining tooth-implant distance following root amputation of a compromised adjacent tooth: A clinical case report.

BACKGROUND: Edentulous sites with limited horizontal tooth-implant distance pose a challenge to clinicians. This case report describes root amputation of an adjacent compromised molar to maintain an optimal tooth-implant distance METHODS AND RESULTS: A 41-year-old female was referred for extraction and implant placement to replace her left, maxillary second premolar (#13), which had been diagnosed with a vertical root fracture. Extraction and ridge preservation of #13 was completed without complication. The 4-month postsurgical clinical examination revealed a narrow mesial-distal distance (5.69 mm) of the edentulous space (#13), which was influenced by the degree of divergence of the mesial buccal root of tooth #14. Cone-beam computed tomography (CBCT) analysis verified a periapical lesion on the mesial-buccal root of tooth #14. The amputation of the endodontically compromised mesial-buccal root of #14 was treatment planned to provide space and facilitate placement of a standard diameter implant without compromising the implant or adjacent teeth. Crestal bone levels were verified and maintained at the 1 year postoperative follow-up. CONCLUSION: The findings of the case report demonstrate how root amputation of a compromised molar is an alternative solution for managing spatial limitations in contemporary implant dentistry. More studies are required to assess the reliability and long-term success of this approach. KEY POINTS: Why is this case new information? There is insufficient evidence on the long-term efficacy of narrow-diameter implants. Clinical treatment guidelines are not sufficiently available. This paper presents an alternative approach to managing a specific scenario where mesial-distance distance is limited using root amputation of an adjacent compromised tooth. What are the keys to successful management of this case? Comprehensive diagnosis and stringent case selection Multidisciplinary treatment planning Evidence-based decision making What are the primary limitations to success in this case? Very specific clinical application; adjacent compromised tooth Long-term follow up is required.

Facially Driven Digital Workflow for Maxillary and Mandibular Milled Implant- Retained Overdentures Using Two Different Unsplinted Attachment Systems: Case Report.

Unsplinted attachment systems for implant overdentures offer various benefits for edentulous patients, including cost-effectiveness, enhanced cleansability, and less need for manual dexterity. This article describes a facially driven digital workflow for fabricating a maxillary implant overdenture retained by conometric-style attachments (Atlantis® Conus) with a palateless design opposing an implant overdenture retained by standard attachments (LOCATOR®). This procedure provides a predictable and accurate technique to digitally scan the master casts with wax rims for articulation and to guide the digital teeth design set-up for a predictable esthetic outcome. The removable prosthesis workflow involves virtual teeth set-up, a 3D-printed trial denture, a milled definitive prosthesis, and intraoral pick-up for both unsplinted attachment systems. The clinical and laboratory steps are described.

A Periodontal Perspective on the Successful Treatment of Recurrent Benign Gingival Lesions Affecting the Anterior Dentition: Two Case Reports.

Recurrent benign gingival lesions occurring in the anterior dentition are clinical dilemmas. While complete removal of such lesions is required to prevent recurrence, this can result in a poor esthetic outcome. Relative to this conundrum, this report discusses the diagnosis, psychologic management, and clinical treatment of two patients with recurring lesions on the facial gingiva of the mandibular and maxillary incisors, respectively. Patient A, a 55-year-old woman, presented with a recurrent peripheral ossifying fibroma (POF); Patient B, a 76-year-old man, presented with a recurrent pyogenic granuloma (PG). Both patients underwent multiple procedures and were ultimately treated without lesion recurrence. The efficacious surgical treatment of recurrent gingival lesions like POF and PG requires an aggressive approach involving lesion removal of the lesion as well as a 1.0- to 2.0-mm margin of normal tissue, underlying alveolar bone, and associated periodontal ligament (PDL). The rationale for this approach stresses the potential periodontal and esthetic ramifications that were considered. In summary, when recurrent benign gingival lesions are localized to the anterior part of the mouth, the approach to their surgical removal should be modified to minimize the extent of gingival recession and other potential esthetic issues.

Photobiomodulation in dental extraction therapy: Postsurgical pain reduction and wound healing.

BACKGROUND: This scoping review and analysis were designed to assess the amount of time spent delivering photobiomodulation (PBM) light therapy after dental extraction to improve postoperative pain and wound healing. TYPES OF STUDIES REVIEWED: The scoping review was performed according to the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Publications were specific for human randomized controlled clinical trials, PBM after dental extraction therapy, and related clinical outcomes. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Analyses were conducted to analyze the prescribed intervals of time (seconds) per application of PBM. RESULTS: Of the 632 studies initially identified, 22 studies fulfilled the inclusion criteria. Postoperative pain and PBM were reported in 20 articles for 24 treatment groups, with treatment times ranging from 17 through 900 seconds and wavelengths from 550 through 1,064 nm. Clinical wound healing outcomes were reported in 6 articles for 7 groups with treatment times ranging from 30 through 120 seconds and wavelengths from 660 through 808 nm. PBM therapy was not associated with adverse events. CONCLUSIONS AND PRACTICAL IMPLICATIONS: There is future potential to integrate PBM after dental extraction therapy to improve postoperative pain and clinical wound healing. The amount of time spent delivering PBM will vary by wavelength and the type of device. Further investigation is needed to translate PBM therapy into human clinical care.

Validating Homogeneity for a Novel 3-Dimensional Tissue Phantom Modeling System of the Human Maxilla.

Silicon phantom models have been utilized to calculate light fluence in patients being treated with Photodynamic Therapy (PDT). This application can be utilized for other non-ionizing wavelength therapies such as Photobiomodulation (PBM). We have developed a novel protocol to validate homogeneity for 3-dimensional silicon phantom models of the human maxilla. Accurately quantifying the light profiles of human tissue can accommodate for varying optical properties that occur between subjects. More importantly, this can help optimize light fluence dosimetry calculations to achieve intended results. Silicon models of identical composition were fabricated into two different shapes: 1 flat-planar cylindrical shaped model, 2) non-flat planar (3-dimensional) mold of the human maxilla. Fabricating homogenous silicon phantom models continues to be a challenge as micro-bubbles can contaminate the compound during the curing process. Integrating both proprietary CBCT and handheld surface acquisition imaging devices confirmed our results to be within 0.5mm of accuracy. This protocol was specifically used to cross-reference and validate homogeneity at various depths of penetration. These results present the first known successful validation of identical silicon tissue phantoms with a flat-planar surface vs. a non-flat 3D planar surface. This proof-of-concept phantom validation protocol is sensitive to the specific variations of 3-dimensional surfaces and can be applied to a workflow used to capture accurate light fluence calculations in the clinical setting.

A Monte Carlo simulation for Moving Light Source in Intracavity PDT.

We developed a simulation method for modeling the light fluence delivery in intracavity Photodynamic Therapy (icav-PDT) for pleural lung cancer using a moving light source. Due to the large surface area of the pleural lung cavity, the light source needs to be moved to deliver a uniform dose around the entire cavity. While multiple fixed detectors are used for dosimetry at a few locations, an accurate simulation of light fluence and fluence rate is still needed for the rest of the cavity. We extended an existing Monte Carlo (MC) based light propagation solver to support moving light sources by densely sampling the continuous light source trajectory and assigning the proper number of photon packages launched along the way. The performance of Simphotek GPU CUDA-based implementation of the method - PEDSy-MC - has been demonstrated on a life-size lung-shaped phantom, custom printed for testing icav-PDT navigation system at the Perlman School of Medicine (PSM) - calculations completed under a minute (for some cases) and within minutes have been achieved. We demonstrate results within a 5% error of the analytic solution for multiple detectors in the phantom. PEDSy-MC is accompanied by a dose-cavity visualization tool that allows real-time inspection of dose values of the treated cavity in 2D and 3D, which will be expanded to ongoing clinical trials at PSM. PSM has developed a technology to measure 8-detectors in a pleural cavity phantom using Photofrin-mediated PDT that has been used during validation.

PDT Light Fluence Phantom Modeling of the Human Pleural Cavity: A Proof-of-Concept Pre-Clinical Study.

We have developed a novel scanning protocol for a life-sized human phantom model using handheld three-dimensional (3D) surface acquisition devices. This technology will be utilized to develop light fluence modeling of the internal pleural cavity space during Photodynamic Therapy (PDT) of malignant mesothelioma. The external aspect of the chest cavity phantom was prefabricated of a hardened synthetic polymer resembling ordinary human anatomy (pleural cavity space) and the internal aspect remained hollow without any characterizations. Both surfaces were layered with non-reflective adhesive paper to create non-uniformed surface topographies. These surface characteristics were established in randomized X-Y-Z coordinates ranging in dimensions from 1-15mm. This protocol utilized the handheld Occipital Scanner and the MEDIT i700. The Occipital device required a minimum scanner-to-surface distance of 24cm and the MEDIT device 1cm respectively. The external and internal aspects of the phantom model were successfully scanned acquiring digital measurements in actual value and converted into a digital image file. The initial surface rendering was acquired by the Occipital device and applied with proprietary software to guide the MEDIT device to fill voided areas. This protocol is accompanied by a visualization tool that allows for real-time inspection of surface acquisition in 2D and 3D. This scanning protocol can be utilized to scan the pleural cavity for real-time guidance for light fluence modeling during PDT, which will be expanded to ongoing clinical trials.

A real-time IR navigation system for pleural photodynamic therapy with a 3D surface acquisition system.

Photodynamic therapy (PDT) has been used intraoperatively to treat patients with malignant pleural mesothelioma. For the efficiency of PDT, it is crucial to deliver light doses uniformly. The current procedure utilizes eight light detectors placed inside the pleural cavity to monitor the light. An updated navigation system, combined with a novel scanning system, is developed to provide real-time guidance for physicians during pleural PDT to improve light delivery. The scanning system consists of two handheld three-dimensional (3D) scanners to capture the pleural cavity's surface topographies quickly and precisely before PDT so that the target surface can be identified for real-time light fluence distribution calculation during PDT. An algorithm is developed to further process the scanned volume to denoise for accurate light fluence calculation and rotate the local coordinate system into any desired direction for a clear visualization during the real-time guidance. The navigation coordinate system is registered to the patient coordinate system utilizing at least three markers to track the light source point position within the pleural cavity throughout the treatment. During PDT, the light source position, the scanned pleural cavity, and the light fluence distribution for the cavity's surface will be displayed in 3D and 2D, respectively. For validation, this novel system is tested using phantom studies with a large chest phantom and 3D-printed lung phantoms of different volumes based on a personal CT scan, immersed in a liquid tissue-simulating phantom with different optical properties, and treated with eight isotropic detectors and the navigation system.

Improving Titanium Implant Stability with Photobiomodulation: A Review and Meta-Analysis of Irradiation Parameters.

Objective: This analysis was designed to present a summary of available evidence that will inform practice and guide future research for photobiomodulation (PBM) after titanium implant placement procedures. Materials and methods: A systematic review was performed according to the Cochrane Collaboration and in line with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) criteria. Two investigators screened the titles and abstracts, and reviewed articles for risk of bias. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Terms were specific to the effects of PBM on dental implant stability. Results: Eight hundred fifty-six studies were identified, and 15 studies fulfilled the inclusion criteria. Light sources included both laser and light emitting diode (LED) devices. Wavelengths ranged from 618 to 1064 nm. The meta-analysis concluded that all 15 published studies were able to safely apply PBM near dental implants without adverse events. Laser and LED wavelengths that reported significant results included 618, 626, 830, 940 (2 × ), and 1064 nm. Conclusions: The use of adjunctive PBM can be safely prescribed after surgical placement of titanium implants. Six groups reported statistical significance for improving implant stability (four laser diode, two LED) in wavelengths ranging from 618 to 1064 nm. The amount of time spent delivering PBM was not a variable that differentiated whether a study reported significant results.

Periodontal and Implant Radiology.

Dental radiography can be used to detect alveolar bone levels around periodontal and peri-implant structures. Periodontal radiographic images can assess alveolar bone height, periodontal ligament, furcation involvement, and evidence of bone destruction. Peri-implant radiographic images can assess the alveolar bone height in relation to the implant structure. As an adjunct to patient care, radiography can aid in the diagnosis of non-health.

Diabetic Serum Inhibits Osteoblast Adhesion to Titanium Surface Through Advanced Glycation End Products: An In Vitro Study.

PURPOSE: Diabetes mellitus has been shown to delay osseointegration of titanium dental implants. This study tested the hypothesis that serum derived from diabetes negatively affects osteoblast adhesion to polystyrene and titanium surfaces, partly through the presence of advanced glycation end products (AGEs). MATERIALS AND METHODS: Twenty-four Sprague-Dawley rats were divided into three groups: normoglycemic control, streptozotocin-induced diabetic group, and diabetic group treated with the AGE inhibitor aminoguanidine. Polystyrene or titanium disks were preincubated in serum derived from each group. Human osteoblasts transfected with green fluorescent protein (GFP) were cultured, and the number of adherent osteoblasts was quantified. High-pressure liquid chromatography (HPLC) was used to fractionate eluates, which were further characterized by western blot with AGE antibody and adhesion assays. In parallel, sera derived from healthy patients, patients with controlled diabetes, and patients with uncontrolled diabetes were utilized for osteoblast adhesion assay and western blot. RESULTS: Diabetic serum significantly reduced the number of adherent osteoblast and osteoblast aggregates on titanium disks, whereas aminoguanidine-treated serum rescued the effect of diabetes on the number of adherent osteoblast aggregates. Fractionated diabetic serum revealed distinct AGE bands at ~100 kDa and 44 kDa, whereas healthy serum did not express any. In human serum samples, both controlled and uncontrolled diabetes led to a significant reduction in the number of adherent osteoblasts on polystyrene and titanium surfaces compared with normoglycemic serum. This correlated with presence of AGEs in western blot in diabetic but not in healthy serum. CONCLUSION: Osteoblast adhesion on the titanium surface was greatly reduced by the exposure of serum derived from diabetic rats or humans. Recovery of osteoblast aggregates by aminoguanidine treatment suggests that AGEs played a role in this negative effect. The correlating presence of AGEs from the fractionated sera of diabetic rats or humans and impaired osteoblast adhesion on the titanium surface further supports this role.