222 Chapter 7 The Liverpool group has presented good results with the zygomatic implant perforated (ZIP) flap technique [82]. This technique for the immediate reconstruction and rapid dental rehabilitation of the low-level maxillectomy defect was first published in 2017 [83] and combines the use of soft-tissue free flap reconstruction of the oral defect combined with the early loading of zygomatic implants whose abutments perforate the flap at the time of primary surgery. With this technique, there is less reliance on bone transfer. Despite the significant challenges, the ZIP flap technique provides full dental rehabilitation within 30 days of surgery and prior to radiotherapy if this is required, with excellent published patient reported outcomes. The choice between surgical reconstruction or (implant retained) obturation of maxilla defects remains controversial, especially for the low-level maxillectomy defects and will largely be determined by comorbidities, institutional experience, personal preferences and financial possibilities. The accuracy and possible consequences of tooth removal prior to radiotherapy Osteoradionecrosis of the jaw is among the most feared late complications observed in patients with HNC treated with RT [84]. To lower the risk of developing ORN, it is important that the jaw areas receiving significant doses of radiation are free of potential sources of infection prior to RT [85]. However, tooth extractions result in a decreased number of functional units and impair mastication and swallowing, contributing to a decreased HRQoL [1, 3, 86-89]. The original Dutch protocol [90] which was re-evaluated in 2018 [20, 91] recommends comprehensive dental assessment and elimination of oral sources of infection where the radiation fields will achieve an expected cumulative radiation dose of ≥40Gy at least 10 to 14 days prior to RT [84, 92]. However, some of the extracted teeth may be extracted redundantly, due to the fact that the estimated radiation dose prior to RT appeared to be lower after completion of RT planning. In Chapter 5, we retrospectively investigated how many of the teeth extracted prior to RT turned out to have been removed redundantly. In addition, we investigated which patient or tumor characteristics were associated with the number of redundantly extracted teeth prior to RT. In Chapter 6, we evaluated the effect of incomplete dentition, tooth extractions prior to RT combined with chemotherapy (CRT) or biotherapy (BRT), and the subsequent loss of functional units on (1) weight loss during CRT/BRT and (2) the need for TF during CRT/BRT for oropharyngeal squamous cell carcinoma (OPSCC).
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