Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Full 3-D digital planning of implant-supported bridges in secondary mandibular reconstruction with prefabricated fibula free flaps

Objectives In the reconstruction of maxillary or mandibular continuity defects in dentate patients, the most favourable treatment is placement of implant-retained crowns or bridges in a bone graft that reconstructs the defect. Proper implant positioning is often impaired by suboptimal placement of the bone graft. This case describes a new technique of a full digitally planned, immediate restoration, two-step surgical approach for reconstruction of a mandibular defect using a free vascularised fibula graft with implants and a bridge. Procedure A 68-year-old male developed osteoradionecrosis of the mandible. The resection, cutting and implant placement in the fibula were virtually planned. Cutting and drilling guides were 3-D printed, and the bridge was computer aided design-computer aided manufacturing (CAD-CAM) milled. During the first surgery, two implants were placed in the fibula according to the digital planning, and the position of the implants was scanned using an intra-oral optical scanner. During the second surgery, a bridge was placed on the implants, and the fibula was harvested and fixed in the mandibular defect, guided by the occlusion of the bridge. Conclusion Three-dimensional planning allowed for positioning of a fibula bone graft by means of an implant-supported bridge, which resulted in a functional position of the graft and bridge.</p

Planned dose of intensity modulated proton beam therapy versus volumetric modulated arch therapy to tooth-bearing regions

Background: Intensity modulated proton beam therapy (IMPT) for head and neck cancer offers dosimetric benefits for the organs at risk when compared to photon-based volumetric modulated arch therapy (VMAT). However, limited data exists about the potential benefits of IMPT for tooth-bearing regions. The aim of this study was to compare the IMPT and VMAT radiation dosimetrics of the tooth-bearing regions in head and neck cancer patients. Also, we aimed to identify prognostic factors for a cumulative radiation dose of ≥40 Gy on the tooth-bearing areas, which is considered the threshold dose for prophylactic dental extractions. Methods: A total of 121 head and neck cancer patients were included in this retrospective analysis of prospectively collected data. We compared the average Dmean values of IMPT versus VMAT of multiple tooth-bearing regions in the same patients. Multivariate logistic regression analysis was performed for receiving a cumulative radiation dose of ≥40 Gy to the tooth-bearing regions (primary endpoint) in both VMAT and IMPT. Results: A lower Dmean was seen after applying IMPT to the tooth-bearing tumour regions (p &lt; 0.001). Regarding VMAT, oral cavity tumours, T3-T4 tumours, molar regions in the mandible, and regions ipsilateral to the tumour were risk factors for receiving a cumulative radiation dose of ≥40 Gy. Conclusions: IMPT significantly reduces the radiation dose to the tooth-bearing regions.</p

Fluorescence grid analysis for the evaluation of piecemeal surgery in sinonasal inverted papilloma:a proof-of-concept study

PURPOSE: Local recurrence occurs in ~ 19% of sinonasal inverted papilloma (SNIP) surgeries and is strongly associated with incomplete resection. During surgery, it is technically challenging to visualize and resect all SNIP tissue in this anatomically complex area. Proteins that are overexpressed in SNIP, such as vascular endothelial growth factor (VEGF), may serve as a target for fluorescence molecular imaging to guide surgical removal of SNIP. A proof-of-concept study was performed to investigate if the VEGF-targeted near-infrared fluorescent tracer bevacizumab-800CW specifically localizes in SNIP and whether it could be used as a clinical tool to guide SNIP surgery.METHODS: In five patients diagnosed with SNIP, 10 mg of bevacizumab-800CW was intravenously administered 3 days prior to surgery. Fluorescence molecular imaging was performed in vivo during surgery and ex vivo during the processing of the surgical specimen. Fluorescence signals were correlated with final histopathology and VEGF-A immunohistochemistry. We introduced a fluorescence grid analysis to assess the fluorescence signal in individual tissue fragments, due to the nature of the surgical procedure (i.e., piecemeal resection) allowing the detection of small SNIP residues and location of the tracer ex vivo.RESULTS: In all patients, fluorescence signal was detected in vivo during endoscopic SNIP surgery. Using ex vivo fluorescence grid analysis, we were able to correlate bevacizumab-800CW fluorescence of individual tissue fragments with final histopathology. Fluorescence grid analysis showed substantial variability in mean fluorescence intensity (FImean), with SNIP tissue showing a median FImean of 77.54 (IQR 50.47-112.30) compared to 35.99 (IQR 21.48-57.81) in uninvolved tissue (p &lt; 0.0001), although the diagnostic ability was limited with an area under the curve of 0.78.CONCLUSIONS: A fluorescence grid analysis could serve as a valid method to evaluate fluorescence molecular imaging in piecemeal surgeries. As such, although substantial differences were observed in fluorescence intensities, VEGF-A may not be the ideal target for SNIP surgery.TRIAL REGISTRATION: NCT03925285.</p

Incidental findings during the diagnostic work-up in the head and neck cancer pathway:Effects on treatment delay and survival

Objectives: As a result of the increasing number of diagnostic scans, incidental findings (IFs) are more frequently encountered during oncological work-up in patients with head and neck squamous cell carcinomas (HNSCC). IFs are unintentional discoveries found on diagnostic imaging. Relevant IFs implicate clinical consequences, resulting in delay in oncologic treatment initiation, which is associated with unfavorable outcomes. This study is the first to investigate the incidence and nature of IFs over the years and establish the effect of relevant IFs on delay. Material and methods: This retrospective study compared two time periods (2010 & ndash;2011 and 2016 & ndash;2017), described associations between relevant IFs and delay in carepathway interval (days between first visit and treatment initiation) and assessed the effect of relevant IFs on overall two-year survival. Results: In total, 592 patients were included. At least one IF was found in 61.5% of the patients, most frequently on chest-CT. In 128 patients (21.6%) a relevant IF was identified, resulting for the majority in radiologist recommendations (e.g. additional scanning). Presence of a relevant IF was an independent significant factor associated with delay in treatment initiation. The risk of dying was higher for patients with a relevant IF, although not significant in the multivariable model (HR: 1.46, p = 0.079). Conclusion: In diagnostic work-up for HNSCC patients, relevant IFs are frequently encountered. As the frequency of additional imaging rises over the years, the number of IFs increased simultaneously. These relevant IFs yield clinical implications and this study described that relevant IFs result in significant delay in treatment initiation

[Three dimensional technology and reconstructions of large defects of the jaw].

Driedimensionale technologie wordt in toenemende mate toegepast binnen de tandheelkunde en binnen de mondziekten-, kaaken aangezichtschirurgie. Een belangrijk toepassingsgebied is de reconstructieve chirurgie, vooral wanneer grote kaakdefecten moeten worden hersteld. Bij deze reconstructies wordt gestreefd naar zowel herstel van de continuïteit van het defect als herstel van de functie. Voor herstel van de functie worden vaak implantaatgedragen dentale constructies gebruikt. Hierbij wordt gebruikgemaakt van met CAD/CAM-vervaardigde suprastructuren, driedimensionaal geprinte boor-/zaagmallen, anatomische modellen, wafers en modellen die de chirurgische uitkomst weergeven. De combinatie van een digitale planning en digitaal vervaardigde suprastructuren en hulpmiddelen biedt peroperatief veel voordelen. Het gebruik van zaag-, boor- en positioneringsmallen zorgt voor een accurate segmentatie en implantaatpositie, waardoor de reconstructie voorspelbaar kan worden uitgevoerd.3D technology is increasingly being applied in dentistry and in oral and maxillofacial surgery. An important field of application is reconstructive surgery, especially in the reconstruction of large defects ofthe jaw. In such cases of reconstruction, the goal is the restoration of both the continuity of the defective area and its function. For the functional restoration implant supported dental structures are often employed. In such cases, CAD/CAM superstructures, 3D printed drill and saw templates, anatomical models, wafers and surgical outcome models are used. The combination of the digital planning and the digital fabrication ofsuperstructures and surgical aids offers many preoperative advantages. The use of saw, drill and positioning templates provides for accurate segmentation and implant positioning, by means of which the reconstruction can be carried out in a predictable way.</p