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Journal of Oral Science & Rehabilitation Volume 2 | Issue 4/2016 75 H e a l i n g o f s m o o t h v s . r o u g h s u r f a c e i m p l a n t s Introduction Osseointegration processes are influenced by many variables, and osseointegration has been foundtoproceedfasterinanimalscomparedwith humans and inthe spongiosa comparedwiththe cortical bone.1 Moderately rough surfaces have shown faster bone apposition compared with turned surfaces. Recently, various implant sur- faces have been discussed with regard to osse- ointegration.2 Mainlythose offour brands repre- sented frequently in the international market were addressed. It was shown that the different surfacetreatmentsoftheimplantsledtodifferent values of the 3-D average roughness over a sur- face (Sa value), as well as of the density of peaks (Sds) and ofthe developed surface area ratio (Sdr). Different values of Sa and Sdr among the various surfaces were reported, including between 0.3 μm and 1.78 μm for Sa and between 24% and 143%forSdr.Itisinterestingtonotethattheorig- inal Brånemark nontreated turned surface pre- sented values of Sa of 0.9 μm and Sdr of 34%.2 A comparison of the sequential healing bet- ween turned and rough (sandblasted, large-grit, acid-etched; SLA) surfaces was performed in an experimental study in dogs.3, 4 Troughs were cre- ated in the space between threads so that, after implantplacement,achamberwasobtained,and only the tips of the threads were in contact with the pristine bone. It was demonstrated that os- seointegration within the chambers proceeded faster and reached higher levels at the SLA com- pared with the turned surfaces. The study of the healing of the hard tissue at untreatedturnedsurfacesandatsurfacesblasted with zirconia particles and subsequently acid et- ched still needs clarification. Hence, the aim of thepresentexperimentwastocompareosseoin- tegration at turned and moderately rough surfa- ces after four months of healing. Materials and methods The research protocol was submitted to and approved by the local ethics committee for an- imal research at the University of the State of São Paolo, Araçatuba, Brazil. C l i n i c a l p r o c e d u r e s Clinical procedures, histologic preparation and data regarding marginal soft- and hard-tissue healing have been reported on previously.5 Brief- ly, six Labrador dogs (each approximately 23 kg and at a mean age of about three years) were used.At anyofthe surgicalsessions,the animals were pre-anesthetized with Acepran (0.05 mg/ kg; Univet-vetnil, São Paulo, Brazil) and sedated with Zoletil(10 mg/kg;Virbac, FortWorth,Texas, U.S.) and Xilazina (1 mg/kg; Cristália Produtos Químicos Farmacêuticos , São Paulo, Brazil), complemented with ketamine (2.5 mg/kg, Cris- tália Produtos Químicos Farmacêuticos). Local anesthesia was also provided. Allpremolars andfirst molarswere extracted at both sides ofthe mandible.Afterthree months of healing, an incision in the center of the alveo- lar crest was performed and full-thickness mu- coperiosteal flaps were elevated. Two osteoto- mies were prepared in each side ofthe mandible in the premolar region and two 10 mm long and 3.8 mm wide titanium Premium (Fig.1a) or Plat- formPremium(Fig.1b)implants(Sweden&Mar- tina, Due Carrare, Italy) were placed in the right and left sides of the mandible, respectively (Fig. 1c). The anterior implants had a turned sur- face (Combed, Sweden & Martina), while the posterior implants had a moderately rough sur- face (ZirTi, Sweden & Martina). The ZirTi surface was first sandblasted using particles of zirconia and subsequently acid et- ched,whilethe Combed surfacewas obtained by a particular tooling process, developed and con- trolled to achieve a more homogeneous and rough surface in comparison with standard ma- chined surfaces. The 3-D parameters to express roughnessanddensityofpeakswereSa =1.399μm and Sds = 0.065 μm2 for the ZirTi surface and Sa =0.600μmandSds=0.314μm2 fortheCombed surface, respectively. Abutments were attached at the top in the implants (Fig. 1d) and the flaps were adapted aroundtheabutment–implantunitstoallownon- submerged healing (Fig. 1e). After the surgical procedures, the animals received ketoflex 1% (0.02 mL/kg; Cetoprofeno, Biofarm Química e Farmacêutica,Jaboticabal,Brazil)andPentabioti- co (Fort DodgeAnimalHealth, Campinas, Brazil). The animalswere kept in kennels and on concre- te runs at the university’s field laboratory with free access to water and fed with moistened balanced dog food. The wounds were inspected daily for clinical signs of complications, and the abutment cleaned. Sutures were removed after two weeks. The animals were euthanatized four months after the surgery, applying an overdose Volume 2 | Issue 4/201675