implants - international magazine of oral implantology International Edition

industry report I _Operating protocol Theplacementoftheimplantswasachievedinthe operating room under general anaesthesia. Animals receivedmedicationperformedaccordingtothefol- lowingprotocol:Intramuscularpremedicationinjec- tion: 3à5ml/kg of Imalgène 1000 + 0.1 ml/kg of Stresnil+1ampouleofatropine;Intravenousinduc- tion of general anesthesia: 0.003 ml/kg of the XKZ mixture (Xylazine, Kétamine, Zolazepam) for a dura- tion of about 30 minutes. Mandibular implants were placed in the space between canine and first premo- lar,andmaxillaryimplantswereplacedeitherdistally ofthelateralincisorormesiallyofthefirstpremolar. _Surgery technique It was the same as in human oral surgery: asepsis ofthesurgeryfield,crestalincision,localisationofthe implant site, boring, threading, implant placement, suturing of gingival flap with interrupted sutures separated stitches. Referenced titanium implants wereused(Figs.1–5). _Operating hazards The main difficulty arose from insufficient height and thickness of the alveolar crest in the mandibular sites and to the relatively important size of the nasal cavities on maxillary sites, which imposes to use im- plants of low diameter and height. Some implants were lost due to a supracrestal or crestal positioning which did not resist animal tongue forces. An infec- tiouseventalsooccurred,resultingintheexclusionof oneanimalfromthestudy. _Sample collection Sampleswerecollectedatday45,afteranaesthe- sia of the animal, following the protocol established with the ethic committee. Bone was cut with a me- chanicalsawaroundtheimplantsites.Sampleswere immerged in formaldehyde and transferred to the imaging department for histomorphometric analy- sis. _Histomorphometric analysis7 Analysis was conducted with CtAn™ software (SkySkan™)dedicatedtoscannerimaging.Bonehis- tomorphometry consisted in the measurements of the parameters reflecting bone structure, microar- chitecture and remodelling. The study of samples including bone and implant permits us to visualize thebonearchitecturearoundtheimplantfromneck toapex,withtheosseointegrationphasebeingatits terminal stage. Parametersconsideredforresultanalysis8 – BV/TV (%): ratio between bone volume and tissue volume; depending on the depth of the analysed volume, V represents cortical or trabecular bone. – IS (mm²): surface of bone intersection with im- plant structure. – TbPF (mm-1 ): trabecular pattern factor, quantify- ingtheinterconnectionofthebone(ratiobetween the numbers of concave and convex surfaces, quantifying the connections inside a 3-D struc- ture). – BS/TV(%):reflectingthedensityofthebonemesh. Analysismethodology(Figs.6–8) A step-by-step analysis as a function of implant depth can be effected by a block of ten frames, each block corresponding to a slice of a thickness of 180µm.Correspondingdatawereplottedasafunc- tion of depth, depth being defined as the centre of the slice. An example of results is shown in Fig. 9. A global analysis of data corresponding to the sum of all slices was done next. For this volume of interest Fig. 7_3-D representation of bone surrounding the implant: the choice of low and high threshold values allows to eliminate metal and any soft tissue. Fig. 8_Corresponding histogram: for this example the selected range (41–96) is taken into account as bone tissue. Fig. 9_Illustration of the histomorphometric analysis method, data are plotted as a function of depth along implant. I 33implants1_2014 Fig. 9 Fig. 8