Assessment of craniofacial implant stability by resonant frequency analysis

Abstract

It is clinically proven that implant stability plays an important role in the subsequent prosthodontics treatment, providing an insight into the outcome of implant therapy. Success of implant therapy depends on biomechanical factors data in most cases. Good implant stability reduces risk of failure. Implant stability measurement researches are mostly based on oral implants. In maxillofacial surgery for anchoring craniofacial epithesis extra oral (EO) implants are used. Thus, there was a need for a pilot study to measure EO implants stability by resonant frequency analysis. The aim of this study was to evaluate clinical stability of craniofacial implants by resonant frequency analysis in correlation with oseointegration during time, implants shape and localisation. Methodology: Micro CT method was used on cadaver model, to determine optimal localisation for implant placement, based on bone decity.In this study 20 patients with orbital, nasal and auricular defects were included. Implant placement points were determinated periorbital, perinasal and in the auricular region. 50 EO implants were placed. Implants used in this study were 38 disc implants (single 8, double 19 and triple disc 11). In the control group 12 screw shape implants were placed, diameter 4.1 mm; 3.5mm length. Stability was measured by Ostell mentor®. Measurements took place three times, immediate after implant placement, after 3 months and at least after 6 months. Results: According to RFA significant increase in implant stability values was noted between all three measurements with all implant types, except with triple disc implants between 3. and 6. month, and screw implants between 0. and 3. month. In comparison between implant groups screw shape implants showed the best stability results and statistically significantly higher values than disc implants. Comparing disc implants there was no statistically significant difference between single, double and triple disc implant values over time, except during the third month, triple disc implants showed significantly higher values compared to single disc implants. Conclusion: In all of the patients Implant stability increased over time which confirmed good osseointegation. After 3 months implants were stable enough for epithesis retention. Measurement of implant stability using RFA is a modern, non-invasive and relatively precise technique, which provides both information about 8 implant stability in the bone and reliable guidance in further course of implant therapy with craniofacial implants.

Klinički je dokazano da stabilnost implantata igra značajnu ulogu u narednim terapijskim fazama i omogućava da predvidimo krajnji ishod rehabilitacije. Kako uspeh implantatno-protetičkog zbrinjavanja često zavisi od biomehaničkih faktora, podatak o stabilnosti implantata smanjuje rizik od neuspeha. Istraţivanja stabilnosti implantata uglavnom se odnose na oralne implantate. U maksilofacijalnoj hirurgiji za fiksiranje kraniofacijalnih epiteza koriste se ekstraoralni implantati. Stoga se ukazala potreba da se sprovede pilot studija u okviru koje bi se izmerila stabilnost kraniofacijalnih implantata analizom rezonantne frekvencije. Cilj ovog istraţivanja bila je procena stabilnosti kraniofacijalnih implantata analizom rezonantne frekvencije u korelaciji sa oseointegracijom u funkciji vremena, oblikom implantata i njihovom lokalizacijom. Metodologija: Na osnovu mikro CT metode odreĎena je gustina kosti na kadaveričnom modelu lobanje radi utvrĎivanja optimalne lokalizacije mesta za ugradnju kraniofacijalnih implantata. Istraţivanjem je obuhvaćeno 20 pacijenata od toga 11 sa orbitalnim, 5 sa nazalnim i 4 sa aurikularnim (kontrolna grupa) defektima. Ukupno 50 EO implantata je ugraĎeno. Korišćeni su implantati oblika diska - 38 (jednostruki 8, dvostruki 19 i trostruki disk 11). U kontrolnoj grupi bilo je ugraĎenih 12 zavrtanj implantata prečnika 4.1 mm; 3.5 mm duţine. Stabilnost je merena Ostell mentor® aparatom. Merenja su vršena tri puta, neposredno po ugradnji implantata, nakon 3 meseca, kao i nakon najmanje 6 meseci. Rezultati: Na osnovu analize rezonantne frekvencije (RFA) značajno povećanje vrednosti implantatne stabilnosti zabeleţeno je izmeĎu sva tri vremena merenja, kod svih tipova implantata, osim kod trostrukih disk implantata izmeĎu 3. i 6. meseca, kao i kod zavrtanj implantata izmeĎu 0. i 3. meseca. PoreĎenjem izmeĎu grupa implantati oblika zavrtnja pokazali su statistički značajno više vrednosti stabilnosti u odnosu na disk implantate. MeĎusobnim poreĎenjem disk implantata nije pronaĎena statistički značajna razlika u stabilnosti izmeĎu jednostrukih, dvostrukih i trostrukih disk implantata tokom vremena, osim u trećem mesecu gde su trostruki disk implantati pokazali statistički značajno više vrednosti u odnosu na jednostruke disk implantate. Zaključak: Kod svih pacijenata implantatna stabilnost povećavala se tokom vremena što potvrĎuje dobru oseointegraciju. Nakon 3 meseca 6 implantati su bili dovoljno stabilni za retenciju epiteza...