Randomized controlled clinical trial to evaluate the concept of treatment for atrophied alveolar ridge reconstruction using Collaged Xenogenic Bone Block (CXBB) versus Autogenous Bone Block (ABB) treatment

Patient recruitment started in August 2017 and ended in December 2020. A total of 155 patients were screened. Out of these, 64 patients entered the clinical trial having fulfilled all inclusion and exclusion criteria. Thirty-two patients were allocated to group CXBB and 32 patients to group ABB. A detailed description on patient recruitment and demographics is displayed in Table 1 and Figure 3. The median thickness of the alveolar ridge at baseline were 2.65± 0.69 mm (CXBB) and 2.95 ±0.76 mm (ABB), with no differences between the groups (fazer a estatistica com Mann-Whitney e acrescentar o valor de p). CXBB was non-inferior to ABB for the increase of atrophied ridge width preceding implant placement (CXBB mean increase was 3.69 ± 1.55 mm; ABB mean increase was 3. 51 ± 1.23 mm) (Table 2 and Figure 4). Secondary performance endpoints demonstrated comparable results for CXBB and ABB in terms of possibility to place an implant (CXBB 96.7%; ABB 100%, p>0,05 ), need to perform a secondary bone augmentation at the time of implant placement (CXBB 13%; ABB 10% , p>0,05 ) and graft loss (CXBB 3.3%; ABB 0%, p>0,05 ). Secondary safety endpoints also showed comparable results for CXBB and bone block in terms of total number of adverse events (CXBB 68.8%; ABB 68.8% ) and occurrence of dehiscence after augmentation (CXBB 31.3%; ABB 37.5% , p>0,05 ) and at implant placement (CXBB 12.5%; ABB 21.9%, p>0,05 ). With regard to early implant failures, exploratory analysis did not suggest differences between treatment groups, considering the patient (p = 0.20) or the dental implant (p = 0.20) as the statistical unit. The total duration of surgery for the CXBB group (55 ± 17 min) was significantly shorter than for the ABB group (121 ± 29 min) (p < 0.0001). Moreover, consumption of analgesic medications was significantly lower in the CXBB group (5.6 ± 8.3) than in the ABB group (11.9 ± 11.6) (p < 0.05). Finally, pain (VAS) scores, from day one to day ten after augmentation procedure, were also significantly lower in the CXBB group (7.7 ± 9.5) than in the ABB group (16 ± 16.4) .