Dental implants have shown a high degree of success in both one- 1–5 and two-stage 6 surgical procedures. Successful osseointegration is evaluated clinically by the absence of mobility and of periimplant inflammation, and radiographically by a stable crestal bone level approximately 1.5 to 2 mm from the micro gap. Despite positive clinical and radiographic findings, some implants fail within a year after loading. A probable explanation for this is that at the histological level, bone-to-implant contact (BIC) was insufficient, and a fibrous seam, undetectable radiographically, formed between the implant and the bone. Different parameters affect the quality of the BIC, eg, bone quality, host factors, implant surface texture, and post surgical healing response. The implant surface texture is one of the major variables that has the ability to affect BIC. A multitude of implant surface topographies (turned, acid-etched, sand-blasted with large grit and acid-etched, titanium plasma sprayed, hydroxy-apatite, Tioblast) are commercially available and have been investigated in laboratory and animal studies. However, an ideal surface topography is yet to be determined.
The EVL implant system (SERF, Decines, France) has been introduced as an improved one-step, cylindro-conical, self-tapping endosseous screw-shaped implant made of grade 2 titanium (Fig. 1). The implant surface in contact with bone is roughened by sandblasting using medical grade alumina particles of 60 to 80 microns in diameter. The emergence profile or neck of the implant is a 2.7 mm polished collar in two portions. The first portion (1.5 mm) is a part of the implant body. The second portion is a removable ring (1.2 mm) designed for the esthetic management of the soft tissue interface.
Successful osseointegration is evaluated histologically by BIC at the light microscopic level. The sandblasted surface of the EVL implant is designed to improve BIC. However, histology is required to ascertain whether or not, and to what extent, this occurs. The purpose of this study was to compare BIC of the one-stage EVL implant with that of the two-stage turned (machined) Branemark (Nobel Biocare, Göteborg, Sweden) implant in the dog model system.
Materials and Methods
Three 1-year-old female beagle dogs (canine) were acquired, examined, and quarantined. After 21 days, each animal was anesthetized with pentobarbital sodium 2.5-mg/kg body weights and maintained on a continuous D5W drip and additional barbiturate as needed. The four premolar teeth of each mandibular quadrant were extracted by hemisection. Primary closure was obtained using continuous horizontal mattress sutures (4–0 absorbable, Vicryl). The animals were observed postoperatively in a recovery area until safely reactive and returned to their cages. Postoperatively, 600,000 units of procaine penicillin was administered IM. As needed, 2.5-mg/kg body weight meperidine was administered for pain control. Each animal was maintained on a puréed/soft diet for 2 weeks. The protocol, all procedures, and all animal care was supervised at New York University Dental Center by the Institutional Animal Care and Use Committee (IACUC) in accordance with the University Animal Welfare Committee requirements.
Placement of the implants was performed 12 weeks after tooth extraction (Fig. 2). This allowed for complete alveolar healing. Each dog was anesthetized as previously described. Osteotomies were prepared for the test implants (SERF, EVL Evolution) and control implants (Branemark, Nobel Biocare) following each of the manufacturer’s recommendations. In dog no. 1, three test implants were placed on one side of the jaw, and four control implants were placed on the other side. In dog no. 2, two test implants were placed in alternation with two control implants on the left and right sides (total 4 tests, 4 controls). In dog no. 3, three test implants were placed on one side and three control implants on the other. Very thin alveolar ridges were present in these particular dogs. However, an attempt was made to place as many implants as possible to allow for evaluation and comparison. The implants were numbered 1, 2, 3, or 4 from anterior to posterior. All test implants were 10 mm in length and 4.0 mm in diameter. All control implants were 10 mm in length and 3.75 mm in diameter. The sites were closed with 3–0 sutures (Vicryl). The test implants were placed with a nonsubmerged protocol, and the flaps were sutured around the implant neck. The control implants, per the manufacturer’s recommendation, were placed with a submerged protocol. The same postoperative medication and care were followed as previously described.
The dogs were killed at the end of a 3-month period of healing with an overdose of Euthasol solution, iv (1 ml/10 lb body weight). The mandibles were removed and block biopsies of each implant site were dissected. All specimens of implants and surrounding bone were sent to the oral pathology laboratory (Hard Tissue Research Laboratory, University of Minnesota, Minneapolis, MN). The examiner at the laboratory was blinded regarding the type of implant on which he was reporting.
The specimens were obtained and then sectioned so that no more than 5.0 mm of bone were surrounding each implant. These specimens were fixed in ten-percent (10%) neutral buffered formalin. Each specimen, including bone and implant, was sectioned longitudinally and mesiodistally in the middle of the implant. All specimens were dehydrated with graded series of alcohols for 9 days. After dehydration, the specimens were infiltrated with a light-curing embedding resin (Technovit 7200 VLC, Kulzer, Germany). After 19 days of infiltration with constant shaking at normal atmospheric pressure, the specimens were embedded and polymerized by 450 mm light with the temperature of the specimens never exceeding 40° C. All specimens were then cut to a thickness of 150 micrometers on an EXACT cutting/grinding system (EXACT Apparatebau, Norderstedt, Germany). The specimens, prepared to a thickness of 50 micrometers by the cutting/grinding method of Donath 7,8 using the EXACT microgrinding system, were then stained with Stevenel’s blue and Van Gieson’s picric fusion. Microphotographs were taken, scanned, digitized, and then analyzed on a Power Macintosh 8500/132 computer using the public domain NIH image program (developed at the U.S. National Institutes of Health and available on the internet at http://rsb.info.nih.gov/nih-image/). The magnification used for the histomorphometric measurements was two times actual size. All measurements were made in pixel and converted to a percentage.
The measurement started at the apical point of the implant collar, continued around the entire implant, and ended at the apical point of the collar on the other side of the microphotograph. In other words, the histomorphometric analysis was made at the sandblasted portion of the implant, excluding the polished collar. Two measurements were made, including bone contact and connective tissue and marrow contact with the implant surface. The distance from the most coronal point of measurement to the first bone contact was counted as “connective tissue.” All contact between bone and implant was considered “bone contact.” Any soft tissue contact with the implant apical to the first bone contact was classified as “marrow.”
Ten test and 11 control implants were placed. However, because of inadequate ridge dimensions only 11 implants, 6 tests, and 5 controls were available for histological evaluation 3 months after placement. Table I presents the data of percentage of bone and marrow and connective tissue contact with the blasted implant surface. The percent of BIC for the test implants varied from 24.9% to 61.6% with an average of 42.7% (Figs. 3 and 4). The percent of marrow and connective tissue-to-implant contact for the test implants ranged from 38.4% to 75.1% with an average of 57.3%. Table II presents the data of percentage of bone and marrow and connective tissue contact with the turned surface implant. The percent of BIC for the control implants varied from 22.1% to 42.6%, with an average of 27.4% (Fig. 5). The percent of marrow and connective tissue-to-implant contact for the control implants ranged from 57.4% to 77.9% with an average of 62.6%. Statistical analysis was not feasible because of the small number of implants that were available for histology.
The influence of implant surface texture on the quality of osseointegration is a controversial issue. It has been demonstrated that a turned surface takes longer to achieve an acceptable degree of osseointegration. 9,10 A very textured surface, sandblasted with very large particles, has been shown in the short-term to have less BIC compared with a moderately textured one. 11 Wennerberg et al studied the BIC of implants blasted with different particle sizes of aluminum oxide and compared them to that of turned screw implants. The results showed that better BIC was always present for the sandblasted implants. 12–14 Although implants sandblasted with 25- and 75-micron particles produced two different surface roughnesses, more BIC was found for the implants blasted with 75-micron particles. 15 However, in a short-term investigation (4 weeks), sandblasting with 250-micron particles created a highly increased surface roughness that was detrimental to osseointegration compared with sandblasting the surface with 25-micron particles. 11
In a comparative study, 16 implants with different surface textures were prepared. They were divided into four groups. The first group of implants was turned on one side and sandblasted with 25-micron particles on the other. The second group of implants was turned on one side and sandblasted with 250-micron particles on the other. The third group of implants was sandblasted with 25-micron particles on one side and sandblasted with 75-micron particles on the other. The fourth group of implants was sandblasted with 25-micron particles on one side and sandblasted with 250-micron particles on the other. Once again the results showed that the blasted surfaces had a significantly greater BIC compared with turned surfaces. Furthermore, blasting with 75-micron particles resulted in a rougher surface, which exhibited significantly greater BIC compared with the 25-micron blasted surfaces. However, at 12 weeks there was no difference in BIC between surfaces blasted with 25- or 250-microns particles. In another study, the authors found that a higher removal torque and more bone-to-metal contact were found for the implants blasted with 75-microns particles compared with the 25-microns-blasted ones. 15
A human histological study compared the percentage of BIC of a dual acid-etched and a turned implant. 17 Specially designed 2-mm wide by 5-mm long, threaded, 2-surfaced titanium implants were manufactured. One side received the dual acid-etched surface, textured side, and one side maintained the turned, machined surface. Eleven implants were implanted in 11 patients in the posterior maxilla. They were retrieved 6 months later. The histological analysis showed a statistically significant difference between the mean percentages of bone-to-implant contact. The textured surface had a mean percentage of bone-to-implant contact, which was higher than that of the turned surface, 72.96% versus 33.98%. In a separate study, 18 this histological result was further confirmed clinically by a higher percentage of success of the dual acid-etched surface compared with the turned surface. In this study, 18 432 implants were placed, 247 of which were acid-etched and 185 turned. The cumulative success rates at 36 months were 95.0% for the dual acid-etched implants and 86.7% for the turned implants. Once again, the textured surface implant had a statistically higher success rate than that of the turned surface implant.
This study found that the test implants had a higher average BIC compared with the control implants, 42.7% versus 27.4%. Moreover, the result of the present investigation is in agreement with previously published results. 11–16 The EVL implant (SERF, Decines, France) surface in contact with bone is roughened by sandblasting using medical grade alumina particles of 60 to 80 microns in diameter. The previously cited articles found that a surface blasted with 75-micron particles had the highest BIC when compared with turned or blasted surfaces with different particle sizes.
The results of this study demonstrate that the sandblasted surfaces of the EVL implant are capable of achieving osseointegration. The degree of BIC of the EVL implants in this study was on average greater than that of the turned surface of the Branemark implant. However, because of the limited number of implants placed in this pilot study, the results should be interpreted with caution. Further animal studies and long-term human clinical investigations are needed and warranted to ascertain the long-term success of this system.
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2. Adell R, Lekholm U, Rockler B, et al. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg. 1981; 10: 387–416.
3. Albrektson T. A multicenter report on osseointegrated oral implants. J Prosthet Dent. 1988; 60: 75–84.
4. Lazzara R, Siddiqui AA, Binon P, et al. Retrospective multicenter analysis of 3i endosseous dental implants placed over a five-year period. Clin Oral Implants Res. 1996; 7: 73–83.
5. Lekholm U, Gunne J, Henry P, et al. Survival of the Branemark implant in partially edentulous jaws: A 10-year prospective multicenter study. Int J Oral Maxillofac Implants. 1999; 14: 639–645.
6. Buser D, Mericske-Stern R, Bernard JP, et al. Long-term evaluation of non-submerged ITI Implants. Part 1: 8-year life table analysis of a prospective multi-center study with 2359 implants. Clin Oral Implants Res. 1997; 8: 161–172.
7. Donath K, Breuner G. A method for the study of undecalcified bones and teeth with the attached soft tissues: The Sage Schliff (sawing and grinding) technique. J Oral Pathol. 1982; 11: 318–326.
8. Rohrer MD, Schubert CC. The cutting-grinding technique for histological preparation of in decalcified bone and bone-anchored implants: Improvement in instrumentation and procedures. Oral Surg Oral Med Oral Pathol. 1992; 74: 73–78.
9. Buser D, Nydegger T, Oxland T, et al. Interface shear strength of titanium implants with a sandblasted
and acid-etched surface: A biomechanical study in the maxilla of miniature pigs. J Biomed Mater Res. 1999; 45: 75–83.
10. Gottlander M, Albrektsson T. Histomorphometric studies of HA-coated and uncoated CP titanium threaded implants in bone. Int J Oral Maxillofac Implants. 1991; 6: 399–404.
11. Wennerberg A, Albrektsson T, Andersson B. Bone tissue response to commercially pure titanium implants blasted with fine and coarse particles of aluminum oxide. Int J Oral Maxillofac Implants. 1996; 11: 38–45.
12. Wennerberg A, Albrektsson T, Johansson C, et al. Experimental study of turned and grit-blasted screw-shaped implants with special emphasis on effects of blasting material and surface topography. Biomaterials. 1996; 17: 15–22.
13. Wennerberg A, Albrektsson T, Andersson B, et al. A histomorphometric and removal torque study of screw-shaped titanium implants with three different surface topographies. Clin Oral Implants Res. 1995; 6: 24–30.
14. Wennerberg A, Ektessabi A, Albrektsson T, et al. A 1-year follow-up of implants of differing surface roughness placed in rabbit bone. Int J Oral Maxillofac Implants. 1997; 12: 486–494.
15. Wennerberg A, Albrektsson T, Lausmaa J. Torque and histomorphometric evaluation of c.p. titanium screws blasted with 25- and 75-microns-sized particles of Al2O3. J Biomed Mater Res. 1996; 30: 251–260.
16. Wennerberg A, Hallgren C, Johansson C, et al. A histomorphometric evaluation of screw-shaped implants each prepared with two surface roughnesses. Clin Oral Implants Res. 1998; 9: 11–19.
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Abstract Translations [German, Spanish, Portuguese, Japanese]
AUTOR(EN): Stuart Froum, DDS*, Dennis Tarnow, DDS PC**, Ziad Jalbout, DDS***, Jean-Pierre Brun, DCD****, Robert Fromental, DCD*****. *Leiter der klinischen Forschungsabteilung, Ashman Abteilung für zahnheilkundliche Implantierungstechnik, Universität New York, zahnheilkundliche Fakultät, New York, New York. **Professor und Vorsitzender, Ashman Abteilung für zahnheilkundliche Implantierungstechnik, Universität New York, zahnmedizinische Fakultät, New York, New York. *** Absolvent, Ashman Abteilung für zahnheilkundliche Implantierungstechnik, Universität New York, zahnmedizinische Fakultät, New York, New York. ****Privat praktizierender Arzt, Schwerpunktpraxis für Zahnimplantation und Kieferorthopädie, Grenoble, Frankreich. ***** Privat praktizierender Arzt, Schwerpunktpraxis für Zahnimplantation und Kieferorthopädie, Lyon, Frankreich. Schriftverkehr: Stuart Froum, DDS, 345 E 24th Street, 8th floor, clinic 8w, Abteilung für zahnheilkundliche Implantierungstechnik (Dept of Implant Dentistry), Universität New York, zahnmedizinische Fakultät, (New York University College of Dentistry), New York, NY 10010. Fax: 212 - 995 - 4337; eMail:email@example.com
ZUSSAMENFASSUNG:Zielsetzung: Ziel der Studie war es, ein einstufiges EVL Implantat mit sandgestrahlter Oberfläche (Serf, Decines, Frankreich) mit einem zweistufigen, gedrehten (maschinell bearbeitet) Branemark Nobel BioCare Implantat bezüglich des Kontaktes zwischen Knochengewebe und Implantat zu vergleichen. Hierzu wurde eine Versuchsreihe an Hunden durchgeführt. Materialien und Methoden: Zur Durchführung der Versuchsreihe wurden drei einjährige Hündinnen der Beagle-Rasse herangezogen. Diese wurden vorab untersucht und unter Quarantäne gestellt. Während bei der ersten Hündin drei Testimplantate auf der einen Seite des Kiefers und vier Kontrollimplantate auf der anderen Seite eingepflanzt wurden, erhielt die zweite Hündin jeweils auf der rechten und linken Kieferseite im Wechsel zwei Testimplantate und zwei Kontrollimplantate (gesamt vier Testimplantate und vier Kontrollimplantate). Bei der dritten Hündin wurden schließlich drei Testimplantate auf der einen Seite des Kiefers und drei Kontrollimplantate auf der anderen Seite eingesetzt. Nach Ablauf von drei Monaten als Heilungszeit wurden die Hündinnen eingeschläfert und deren Kiefer zur histologischen Auswertung vorbereitet. Letztendlich konnten insgesamt elf Implantate, sechs Testimplantate und fünf Kontrollimplantate, zur histologischen Bewertung herangezogen werden. Ergebnisse: Die Testimplantate wiesen bezüglich des Kontaktes von Knochengewebe zu Implantat prozentual gesehen eine Variationsbreite von 24,9 % bis 61,6 % auf, mit einem durchschnittlichen Wert von 42,7 %. Bei den Kontrollimplantaten schwankte der Prozentsatz für den Knochengewebs-Implantat-Kontakt zwischen 22,1 % und 42,6 %. Hier lag der Durchschnitt bei 27,4 %. Schlussfolgerung: Im Durchschnitt wiesen die EVL Implantate bezüglich des Kontaktes von Knochengewebe zu Implantat bessere Ergebnisse auf als die Branemark Implantate mit gedrehter Oberfläche. Aufgrund der geringen Anzahl von zur Untersuchung zur Verfügung stehenden Implantaten sollten die Ergebnisse der Pilotstudie allerdings nicht ohne weitere Reflexion zur Verallgemeinerung herangezogen werden.
SCHLÜSSELWÖRTER: Integration in das Knochengewebe, Knochengewebs-Implantat-Kontakt, sandgestrahlt, maschinell bearbeitet/gedreht
AUTOR(ES): Stuart Froum, DDS*, Dennis Tarnow, DDS, PC**, Ziad Jalbout, DDS***, Jean-Pierre Brun, DCD****, Robert Fromental, DCD*****. *Director de Investigación Clínica, Departamento Ashman de Odontología de Implante, Facultad de Odontología de la New York University, Nueva York, Nueva York. **Profesor y Jefe, Departamento Ashman de Odontología de Implante, Facultad de Odontología de la New York University, Nueva York, Nueva York. ***Graduado, Departamento Ashman de Odontología de Implante, Facultad de Odontología de la New York University, Nueva York, Nueva York. ****Práctica privada limitada a implantes y periodóntica, Grenoble, Francia. *****Práctica privada limitada a implantes y periodóntica, Lyon, Francia. Correspondencia a: Stuart Froum, DDS, 345 E 24th Street, 8th Floor, Clinic 8w, Dept. of Implant Dentistry, New York University College of Dentistry, New York, NY 10010. Fax: 212-995-4337; Correo electrónico:firstname.lastname@example.org
ABSTRACTO: PROPÓSITO: El propósito de este estudio fue comparar el contacto del hueso al implante de la superficie pulida con arena de una sola etapa del implante EVL (SERF, Deeines, Francia) con el implante Branemark Nobel BioCare fabricado a máquina de dos etapas en un modelo en perros. MATERIALES Y MÉTODOS: Tres perras sabuesos (beagle) (caninas) de un año fueron adquiridas, examinadas y puestas en cuarentena. En la perra n.° 1, se colocaron tres implantes de prueba en un costado de la mandíbula mientras que cuatro implantes de control se colocaron en el otro costado. En la perra n.° 2, se colocaron dos implantes de prueba alternados con dos implantes de control en el costado izquierdo y derecho (total de 4 pruebas y 4 controles). En la perra n.° 3, se colocaron tres implantes de prueba en un costado y 3 implantes de control en el otro. Después de un período de tres meses de curación, se sacrificaron las perras y se seccionaron las mandíbulas para la preparación histológica. Once implantes, seis de prueba y cinco controles estuvieron disponibles para la evaluación histológica. RESULTADOS: El porcentaje de BIC (contacto de hueso a implante) de los implantes de prueba variaron de 24,9% a un 61,6% con un promedio de 42,7%. El porcentaje de BIC para los implantes de control varió desde 22,1% a 42,6%, con un promedio de 27,4%. CONCLUSIÓN: El grado de contacto del hueso al implante de los implantes EVL fue como promedio mayor que el de la superficie maquinada del implante Branemark. Sin embargo, debido a la cantidad limitada de implantes colocados en este estudio piloto, los resultados deberán ser interpretados de manera cautelosa.
PALABRAS CLAVES: oseointegración, contacto del hueso al implante, pulido con arena, maquinado/torneado
AUTORES: Stuart Froum, DDS*, Dennis Tarnow DDS, PC**, Ziad Jalbout DDS***, Jean-Pierre Brun DCD****, Robert Fromental, DCD*****. *Diretor de Pesquisa Clínica, Departamento de Odontologia de Implante Ashman, Faculdade de Odontologia da Universidade de Nova York, Nova York, Nova York. **Professor e Presidente, Departamento de Odontologia de Implante Ashman, Faculdade de Odontologia da Universidade de Nova York, Nova York, Nova York. ***Profissional Graduado, Departamento de Odontologia de Implante Ashman, Faculdade de Odontologia da Universidade de Nova York, Nova York, Nova York. ****Clínica particular especializada em odontologia de implantes e periodontia, Grenoble, França. *****Clínica particular especializada em odontologia de implantes e periodontia, Lyon, França. Correspondências devem ser enviadas a: Stuart Froum DDS, 345 E 24th Street, 8th floor, clinic 8w, Dept of Implant Dentistry, New York University College of Dentistry, Nova York, NY 10010. Fax: 212 995-4337; Email:email@example.com
SINOPSE:OBJETIVO: o propósito deste estudo foi a comparação da área de contato entre o osso e o implante EVL com superfície jateada com areia em uma fase (SERF, Decines, França), com o contato do implante Branemark Nobel BioCare “rodado” em duas fases (usinado) em um sistema de modelo canino.
MATERIAIS E MÉTODOS: três cadelas da raça Beagle de um ano de idade foram adquiridas, examinadas e colocadas em quarentena. No cachorro no 1, foram colocados três implantes de teste em um lado da mandíbula enquanto quatro implantes de controle foram colocados no outro lado. No cachorro no 2, dois implantes de teste foram colocados alternando com os dois implantes de controle no lado esquerdo e direito (total: 4 de teste e 4 de controle). No cachorro no 3, foram colocados 3 implantes de teste em um lado e 3 implantes de controle no outro. Após um período de três meses de cicatrização, os cachorros foram sacrificados e as mandíbulas foram cortadas em seções para a preparação histológica. Encontraram-se disponíveis onze implantes, sendo seis de teste e cinco de controle, para a avaliação histológica. RESULTADOS: o percentual de contato entre o osso e o implante (BIC, ou bone-to-implant contact) para os implantes de teste variaram de 24,9% a 61,6%, com uma média de 42,7%. O percentual de BIC para os implantes de controle variaram de 22,1% a 42,6%, com uma média de 27,4%. CONCLUSÕES: o grau de contato entre o osso e os implantes EVL foi em média maior que a superfície “rodada” do implante Branemark. Entretanto, devido ao número limitado de implantes colocados em um estudo piloto, deve-se interpretar os resultados com cuidado.
PALAVRAS-CHAVES: osseointegração, contato entre o osso e o implante, jateado com areia, usinado/rodado