Assisted Wound Healing and Vertical Bone Regeneration with Simultaneous Implant Placement: A Histologic Pilot Study.

PURPOSE: To evaluate the effectiveness of platelet-rich fibrin (PRF) and freeze-dried bone allograft (FDBA) in vertical bone augmentation with immediate implant placement using histologic analysis. MATERIALS AND METHODS: Six Merino sheep received a total of 36 Brånemark MKIII implants; three implants were placed supracrestally in each tibia with vertical exposure of four threads. Each implant received one of the three grafting options (MinerOss + PRF or MinerOss or PRF). The grafting materials were covered with a resorbable collagen membrane (Mem-Lok 30 × 40 mm, BioHorizons). Animals were sacrificed at 4 and 8 weeks, respectively, and specimens were prepared and collected for histologic analysis. Ground sections and decalcified sections were prepared. RESULTS: The various stages of graft integration into native bone and the implant were observed at different time points, and comparison between the three grafting options was possible. Osteogenic potential with vertical generation of bone was observed in the three groups. At week 4, woven bone formation at the bone graft interface was observed; new bone did not appear to be organized at week 4. At week 8, the graft appeared to be fully replaced by vital mature and well-organized bone arranged in lamellae with osteocytes encapsulated within the bone. The vertical bone gain at 8 weeks was higher for the PRF + MinerOss group with viable bone extending above the first thread. Both the MinerOss and PRF groups had vertical bone gain extended to the second thread. CONCLUSION: MinerOss appeared to be effective in vertical bone augmentation with simultaneous implant placement. PRF enhanced vertical bone augmentation when combined with MinerOss.

EFFECTS OF TWO CONTRAST INJECTION PROTOCOLS ON FELINE AORTIC AND HEPATIC ENHANCEMENT USING DYNAMIC COMPUTED TOMOGRAPHY.

This prospective study compared aortic and hepatic enhancement achieved using a contrast injection protocol with a fixed rate of 5 ml/s vs. that achieved using a protocol with fixed injection duration of 20 s in eight cats. Cats were assigned into two groups (Group 1, rate 5 ml/s; Group 2, duration 20 s). The dose of contrast was the same in both groups (740 mgI/kg). Regions of interest (ROI) were drawn in the aorta and liver for transverse scans acquired at the hepatic hilus. Time to peak aortic enhancement occurred significantly earlier in Group 1 (M = 11s, SD = 1.63) than in Group 2 (M = 25.5 s, SD = 2.51). Peak aortic enhancement was significantly higher in Group 1 (M = 1906.51 HU, SD = 368.64) than in Group 2 (M = 745.08 HU, SD = 201.84). Duration of aortic enhancement equal to or above 300 HU was statistically longer in Group 2 (M = 24.5 s, SD = 8.39) than in Group 1 (M = 10 s, SD = 1.63). There were no significant differences in time to peak liver enhancement, peak liver enhancement, or duration of hepatic arterial phase between groups. Findings supported the hypothesis that longer injection duration results in a broader bolus geometry with a longer time to peak and a lower peak aortic enhancement in cat. This strong influence of injection duration on timing of aortic enhancement may help future users optimize protocols for CT angiography of the aorta and multiphasic evaluation of the liver, pancreas, and small intestine.

A comparison of low dose tiletamine-zolazepam or acepromazine combined with methadone for pre-anaesthetic medication in cats.

OBJECTIVE: To compare the level of sedation, cardiorespiratory changes, and quality of recovery in cats receiving methadone plus either low dose tiletamine-zolazepam or acepromazine for premedication prior to general anaesthesia for neutering. STUDY DESIGN: Prospective, randomized, blinded clinical study. ANIMALS: Twenty cats 0.54 ± 0.12 years-old (mean ± SD), weighing 3.17 ± 0.65 kg (10 male and 10 female). METHODS: Cats were allocated randomly to receive intramuscularly either 0.03 mg kg(-1) acepromazine (ACE) or 3 mg kg(-1) tiletamine-zolazepam (TZ), both regimens combined with 0.2 mg kg(-1) methadone for premedication. Sedation was assessed 25 minutes after premedication using a visual analogue scale (VAS) and a simple descriptive scale (SDS). Anaesthesia was induced with alfaxalone and maintained with isoflurane. Physiological parameters were recorded at 1, 3 and 5 minutes post-endotracheal intubation. Recovery from cessation of isoflurane was timed and quality assessed using a SDS and a VAS. Data was analysed with Mann-Whitney U-test, students t-test, anova or ordinal logistic regression as relevant. Significance was taken as p < 0.05. RESULTS: Sedation was more pronounced in TZ than ACE as indicated by higher VAS (67 ± 21 versus 13 ± 5) and SDS scores [4 (1-4) versus 1 (0-1)]. Following sedation, Heart (HR) and respiratory (fR ) rates did not differ between groups. After anaesthetic induction, at times 1, 3 and 5 HR, systolic arterial pressure and end tidal carbon dioxide were significantly higher and fR was significantly lower in TZ than ACE. Recovery quality was similar between groups. In both groups, times to extubation, head lift and sternal recumbency were similar, but time (minutes) until standing was significantly longer in TZ (31 ± 16) than ACE (18 ± 11). CONCLUSION AND CLINICAL RELEVANCE: Low dose tiletamine-zolazepam combined with methadone provided superior sedation to ACE. Recovery quality was similar, although time to standing was longer.