Bone Augmentation with Bioactive Glass in Three Cases of Dental Implant Placement Antonietta M. Gatti, Leopoldo A. Simonetti, Emanuela Monari, Stefano Guidi, David Greenspan To cite this version: Antonietta M. Gatti, Leopoldo A. Simonetti, Emanuela Monari, Stefano Guidi, David Greenspan. Bone Augmentation with Bioactive Glass in Three Cases of Dental Implant Placement. Journal of Biomaterials Applications, 2006, 20 (4), pp.325-339. ￿10.1177/0885328206054534￿. ￿hal-00570766￿ HAL Id: hal-00570766 https://hal.archives-ouvertes.fr/hal-00570766 Submitted on 1 Mar 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Bone Augmentation with Bioactive Glass in Three Cases of Dental Implant Placement ANTONIETTAM.GATTI,* LEOPOLDOA.SIMONETTI,EMANUELAMONARI, STEFANO GUIDI AND DAVID GREENSPAN TheNationalInstituteof Physics of Matter Laboratory of Biomaterials, Department of Neurosciences University of Modena andReggio Emilia Via delPozzo71, 41100 Modena – Italy ABSTRACT: This study reports the clinical use of a bioactive bone graft material, PerioGlas(cid:1), in the treatment of dental extraction sites before dental implantplacement,toeffectboneregenerationandtogiveearlyfixationtothe implant. PerioGlas(cid:1), granules, ranging from 90 to 710mm, are implanted after tooth extractioninthreepatients;after6monthsbonebiopsieswereperformedinthe siteoftheglassimplantationandobservedunderElectronScanningMicroscopy. All the granules showed a biodegradation involving precipitation of calcium phosphate that worked as a scaffold for osteoblasts colonization. All cases examined showed the bioactivity of PerioGlas(cid:1) granules resulting in new bone formationandbiodegradationoftheglass.Afteratwo-yearclinicalfollow-upall theimplants were successfully loadedand appeared stable. KEY WORDS: bioactive materials, implants, dentistry, bonedefects. INTRODUCTION The use of dental implants to restore function in partially/ completely edentulous patients has been highly successful in recent years [1,2]. With the development and improvement in dental *Authortowhomcorrespondenceshouldbeaddressed.E-mail:[email protected] JOURNALOFBIOMATERIALSAPPLICATIONS Volume20—April2006 325 0885-3282/06/040325–15$10.00/0 DOI:10.1177/0885328206054534 (cid:2)2006SAGEPublications 326 A.M.GATTIETAL. implanttechnology,theclinicianhasmoretoolstohandlecomplexcases ofosseousdefectsusingbonegraftmaterialstoaugmentthesiteswhere the volume of bone would otherwise prohibit the implant placement. There are various materials available for correcting dento-alveolar ridge deformities and augmenting other types of osseous defects. These materials include autogenous bone, demineralized freeze-dried bone allograft (DFDBA), xenografts, alloplasts, and various resorbable and non-resorbable membranes. Autogenousboneisstillconsideredthegoldstandardinbonegrafting procedures [3–5], notwithstanding its limited availability and the need for a second surgery. The results can be variable, depending on the quality/quantity of the bone used, the preparation of the bone, and the method of placement into the surgical site. Although there have been reports showing poor results with DFDBA when implanted into extraction sites [4,6], it is widely used for bone grafting. Xenografts have also been a popular choice and are said to stimulate bone formation and to be resorbable as well. Recent reports have shown that these materials remain in the implant site for years before resorbing. The persistence of the material in the site over extended time periods could lead to stress concentration and ultimate bone failure [7–9]. In addition, the presence of proteins of bovine origin in certain xenograft materials, especially in Europe, is still being investigated in relation to the problem of the transmissible spongiform encephalopathy, a disease affecting cattle, but likely transmissible to humans [10]. A number of alloplastic materials have been developed to overcome many of the problems described here. These materials include calcium phosphates, calcium sulfates, and bioactive glasses [11–15]. In general, these materials are said to be osteoconductive, and may or may not be resorbable. Different types of bioactive glass have been used clinically to regenerate bone loss as a result of periodontal disease for over 10 years. The bioactivity of these glasses was also verified for physical parameters, like surface morphology and granule size, and not only their chemical composition. As an example, we quote the work of Ducheyne [16], who synthetized a glass called Biogran(cid:1) that has the samechemicalcompositionofPerioGlas(cid:1),anddiffersinthegranulesize range, 300–500mm instead of 90–710mm, and it is claimed to have a higher biocompatibility. There has been a number of clinical studies that have demonstrated consistent results in treating intrabony defects [17]. One study showed that the clinicalresults ofonetype ofbioactiveglass were equivalentto DFDBAintreatingtwoandthreewalldefects[18].Morerecentstudies BoneAugmentationwithBioactive Glass 327 have shown that whenusedto regeneratebonein fresh extraction sites or to augment the maxillary sinus, these materials fully resorb over a 6-to-13-month time period [19,20]. The materials have been said to be osteostimulative [21] in that they enhance the bone regeneration of the defect site. The purpose of this study is to histologically and ultrastructurally evaluate three cases of bone augmentation procedures performed in the mandible, using bioactive glass with a subsequent dental implant placement and to report the resorbability of the bioactive glass and the bone regeneration in the implantation site. MATERIALS AND METHODS The cases included in this study and reported in Table 1 are all mandibular teeth that were diagnosed with advanced periodontal disease in need of extraction. All the patients were treated with the following medications: (1) Amoxicillin (1g bid, for 1 day before tooth extraction and continued for 6 days), (2) Metasone retard (1mg/day for 5 days) and (3) NSAID on demand bid. Probing depth was measured beforetoothextractionineachcase.Theimplantsiteswerepreparedby drilling at a speed not exceeding 40rpm and assuring torque at 32N, without irrigation. This facilitated the harvesting of autogenous bone required to be mixed with bioactive glass (PerioGlas(cid:1), Novabone, USA) (composition: 45% (in weight per cent) SiO , 24.5% CaO, 24.5% Na O, 2 2 4% P O ; size: 90–710mm) and for a better control of implant 2 5 alignment. Radiographs were obtained at various times including baseline, immediate post-operative and at 6, 12, 18 (data not shown) and 24 months. At each follow-up, routine hygiene was performed. With prior consent from the patients, biopsies were taken during the six-month follow-up visit. Case 1 – The patient presented with a periodontal abscess of an endodonticallyinvolvedmolarwith3(cid:1) furcationlesionhavingaprobing depth of 7mm, necessitating extraction (Figure 1(a)). The patient was prescribed prophylactic antibiotics for 1 week before extraction of 4.6 Table 1. List ofthecases. Case Gender Age GGhealth Smoker BOP(%) FMPS(%) 1 M 40 Good Yes <20 <20 2 M 60 Good No <20 <20 3 F 42 Good No >20 >20 GGHealth–Goodgeneralhealth;BOP–Bleedingonprobing;FMPS–Fullmouthplaquescore. 328 A.M.GATTIETAL. Figure1. (a)X-rayimageofagrade3furcationinvolvementinthelowerrightfirstmolar (seearrow);(b)implantsiteandsocketfilledwiththebioglassgranulesaftertheimplant procedure(seearrows);and(c)fixtureandhealingabutment6monthsaftertheimplant. Arrowsshowthebiopsysites. (lowerrightfirstmolar).Afullthicknessflapwasraisedwithoutvertical releasing incisions, without compromising the flap vascularization and the tooth was extracted, taking care to preserve the bone structure. The socket was then thoroughly cleaned and the implant (Osseotite(cid:1) Standard, 3i Implant Innovation, USA) placed in the interradicular bone. The implant length was chosen to ensure primary stability in the bone. The remaining socket of the extraction site, around the implant, was filled with a mixture of PerioGlas(cid:1) and autogenous bone. The autogenous bone had been harvested from the drilling process during the preparation of the implant site. No additional sites were used to harvest bone (Figure 1(b)). A healing abutment was placed on the implant and the implant was covered for 6 months. At the time of placement of the abutment (6 months from surgery) a biopsy was performed distal to the abutment (Figure 1(c)). An additional small biopsy was taken from the soft tissue around the collar of the implant. The healing abutment was replaced on the implant and the final restoration was made 2 weeks after the biopsy. The abutment was tightened at 32N with a dynamometric tool controlled by endo-oral radiography (Trophy RGVui Digital Radiography System, Trophy Radiology, France) using Rinn technique and personal bite blocks to ensure consistent alignment. Case 2 – The patient presented with a high mobility of the cantilever bridge due to root fracture of 3.5 (lower left second premolar) (Figure 2(a)). The bridge was then removed and the tooth extracted and subsequently its socket was filled with a mixture of PerioGlas(cid:1) andautogenousbone(Figure2(b)and(c))tomaintainpropervolumeof bone for the esthetics of the final prosthesis. An implant could not be placed in the socket because of the lack of buccal bone, as an implant withdimensionsof4mmdiameterand10mmlengthwouldcompromise the implant primary stability in the alveolar bone. A length more than 10mmcouldpenetratethemandibularnervecanal,causingparesthesia. BoneAugmentationwithBioactive Glass 329 Figure 2. (a) X-ray image of wide bone resorption due to root fracture (see arrow); (b)arrowshowsthebonesocketbeforebioactiveglassimplantation;and(c)bonesocket filledwithPerioGlas(cid:1) granulesplusautogenousbone(seearrows). Figure3. PanoramicX-ray.Arrowsindicatethe4.7areabeforeoperation. Full thickness flap with vertical mesial release incision was performed for a two-stage implant technique distally positioned to the graft- filled socket (Osseotite(cid:1) Standard, 3i Implant Innovation, USA). The periosteum was released before suturing. At 6 months, a biopsy was taken from the filled socket and the implants were loaded. UCLA abutments (3i Implant Innovation, USA) were placed and tightened at 32N using a dynamometric tool controlled by endo-oral radiography (TrophyRGVuiDigitalRadiographySystem,TrophyRadiology,France) using Rinn technique and personal bite blocks. Case3–Thepatientpresentedwithanadvancedperiodontallesionas a result of poor oral hygiene and exhibited bleeding on probing (BOP) and full mouth plaque score (FMPS) >20%, and a probing depth of about 12mm (Figure 3). 330 A.M.GATTIETAL. In this case, 4.7 (lower right second molar) was extracted and the socket was filled with a mixture of PerioGlas(cid:1) and the patient’s blood. The graft site was then covered with a PLA membrane (Atrisorb(cid:1), Atrix Laboratories, USA) for better protection and the mesiovestib- ular periodontal pocket of 4.8 (lower right third molar) was also grafted as it presented a 7-mm probing depth. The periosteum was dissected to release the flap and to achieve a better primary healing of the wound. A biopsy was taken after 6 months and two implants (Osseotite(cid:1) Standard, 3i Implant Innovation, USA) were placed with a one-step technique keeping mounting devices in place for a better healing of the soft tissues. The implantswere loaded after 6 months and intraoral radiographs (Trophy RGVui Digital Radiography System, Trophy Radiology, France) and orthopantomographs (Cranex Tome CEPH, Soredex, Finland) were taken during the two-year follow-up visit. The biopsies were fixed in 4% paraformaldehyde and dehydrated in ethanol. After embedding in polymethylmethacrylate, the samples were sectioned with a diamond saw (Accutom, by Struers, Denmark) into a 200-mmthickanda20-mmthickslice,respectivelyforscanningelectron microscopy (SEM) (QUANTA-ESEM by FEI, The Netherlands) and for histological observation (Standard 25, Zeiss, Germany). The thin non- decalcified sections were stained with Stevenel’s blue/Van Gieson’s picrofuchsin or hematoxylin–eosin, suitable to show calcium deposition and bone morphology. The 200-mm thick sections were first micro- radiographed and then polished and prepared for SEM observations that were performed both in secondary emitted and backscattered mode (BSE). Elemental analyses and X-ray dot maps were carried out with an energy dispersive system (EDS, by EDAX, USA) to detect the topographic distribution of the elements in the PerioGlas(cid:1) granules after implantation. RESULTS ThehistologicalandSEManalysesofthebiopsyofCase1takenfrom the soft tissue around the implant collar show minimal inflammatory reaction; the cellular reaction around the particles is characterized by normal connective tissue with little infiltrate, demonstrating the compatibilityofbioactiveglassparticlesincontactwiththesofttissues. The outer layer of the particles shows signs of infiltration and hematoxylin–eosin staining indicates the presence of a calcium-rich layer. The degradation also affects the particle core where cell colonization is observed (Figure 4). BoneAugmentationwithBioactive Glass 331 Figure4. Histologic hematoxylin–eosinstainedsectionofthe biopsyin thebonedefect (10(cid:2)).Glassgranulesarestillvisibleafter6monthsfromimplantation(seearrows). Figure5. Scanningelectronmicrographofthetotalbonebiopsy.Glassgranules(whiter) arestillvisibleinbone(seearrows). At low magnification under the SEM (Figure 5), the biopsy shows bone and granules that are not yet completely resorbed. They appear whiter since they are electronically denser than bone. The grey level contrast in the image clearly delineates older bone (lighter grey) from newly formed bone. Intheapicalpartofthebiopsy,widezonesofmineralizationareseen, probably due to autogenous bone pieces that were mixed with PerioGlas(cid:1) during implantation and due to a more intimate contact with the bone walls. Trabecular bone was seen to have grown directly onto the surface of the glass particles away from the bone walls. Some granules appear to have an empty core indicating a resorption of the particles. In addition, new bone can be seen growing within the 332 A.M.GATTIETAL. Figure6. (a)SEM–BSEimageofadegradedglassgranule(whiterarea)surroundedby newbone.Insidetheparticlethereisapouchwherenewboneisforming.Thecrackscross theouterlayer.Thearrowindicatestheinterfaceoftheglassgranule–newgrownbone. (b)EDSspectrumofthe X-rayanalysesin theouter layershowingmainlythe presence ofcalciumandphosphorus.(c)X-raydotmapsforcalcium(Ca),carbon(C),silicon(Si),and phosphorus(P)indicatethetotalglasstransformationinacalciumphosphate. excavated pouch of the bioactive glass particle in the SEM image (Figure 6(a)). The appearance of the material adjacent to the newly formed bone is similar to precipitated calcium phosphate (Figure 6(b)). After 6 months of implantation, the glass underwent a physical- chemical transformation and a significant part had already been transformed into calcium phosphate, as shown by the X-ray dot maps for silicon, calcium, and phosphorus (Figure 6(c)). BoneAugmentationwithBioactive Glass 333 The bioglass bioactivity mechanism was already described by many authors [22,23] and it could be divided into different steps: (a) ionic diffusiveprocessesfromtheglass,(b)itstransformationintoahydrated gel, (c) contradiffusion from the extracellular matrix toward the glass surface, and finally (d) precipitation of calcium phosphate in the glass. Radiographic images of the implant site after 6 (Figure 1(c)) and 24months(Figure7)showgoodmaintenanceofthe bonecollar around implant. HistologicalobservationofthebiopsyofCase2showssignificantbone growth among the bioactive glass particles, which appear degraded: some are intimately connected to the newly formed bone while others are still surrounded by noninflammatory connective tissue. Figure 8 is an undecalcified histologic image (Van Gieson’s picrofuchsin) of Figure7. X-rayimagesofCase1implantsiteafter24-monthfollow-up. Figure 8. Histological view of a picrofuchsin-stained section. (10(cid:2)) No sign of adverse tissuereactionsarevisible.