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Titanium extracts enhance epithelial cell growth
Oral Abstract SessionI: Maxillofacial Reconstruction Kaban et al. (1) in which a mandibular defect heals in the presence of demineralized bone powder (DBP) but does not close spontaneously. We previously reported (2) that 45 Gy @‘Coin fifteen 3 Gy fractions inhibits the healing of DBP filled bony defects when surgery is performed 2 or 4 weeks after completion of irradiation (XRT). In the present study we wished to determine the level of a single dose of 6oCo XRT that inhibits DBPinduced bone formation. Previous studies suggested that there is a difference in the response of tissues to irradiation dependent on pre or post operative administration and the interval between surgery and irradiation. Therefore, rather than arbitrarily choosing a single timepoint or sequence of irradiation and surgery, we decided to study two groups: 1. Surgery then XRT 1,3,7 or 14 days later; 2. XRT then surgery 1,3,7,14,21 or 28 days later. We did not include the later timepoints (21, 28 days) in the former group because DBP-induced bone formation is already almost complete by 21 days. At least 4 experimental and 2 control rats were included at each timepoint. The rats were sacrificed 6 weeks after surgery and the defects evaluated clinically, histologically and densitometrically for bony healing. Statistical analysis was performed using SAS ANOVA and paired Students T tests. A dose of 20 Gy 6oCo was insufficient to inhibit osteoinduction by DBP in our model system. We repeated the study using a single dose of 30 Gy ‘?Zo. At this level of XRT there was inhibition of bone induction by DBP, but the rats became debilitated. A single 25 Gy “OCoexposure was sufficient to inhibit bone formation in the mandibles, yet be well tolerated by the rats. The XRT significantly (P < .05) decreased the DBP-induced bone fill, bone mineral content (BMC) and bone mineral density (BMD) of the mandibles. The bone fill, BMC and BMD of the DBP filled defects in the irradiated mandibles were not significantly different at the various timepoints. However, the lowest percentage bone fill was observed in those in which surgery was followed by XRT 1 day later and those with XRT then surgery 14 days later. Thus we have developed a reproducible rat model in which a single dose of 25 Gy “OCo XRT significantly inhibits bone formation in a DBP filled defect. We have also developed methodology for noninvasive quantitation of bone formation using microdensitometry. We are continuing our work with the rat mandible irradiation model, and are currently developing two and three dose schedules that are comparable in effect to the single dose of irradiation. References Kaban et al.: J Dent Res 60:1356,1981 Lorente, rionot? J Dent Res 66:170,1987 Supported by AAOMS 08195 68
Henny Fellowship and NIDR Grant DE
Titanium ExtractbEnhanceEpitheliul Cell Growth John H. Campbell, DDS, Orofacial Medicine Div., Head and Neck Center, Sisters of Charity Hospital, 2121 Main St, Buffalo, NY 14214 (Edsberg, L.) Metals in the form of wires, bone plates, or transmucosal implants are commonly used in reconstruction of congenital or acquired facial anomalies. One clinical problem often encountered with transmucosal implants is a hyperplastic tissue response adjacent to the implant. This investigation was undertaken to assess in vitro growth effects of stainless steel and titanium on human mesenchymal and epithelial cells to elucidate the etiology of these clinical findings. CCL-135, a human fibroblast-like lung cell culture, was acquired from the American Type Culture Collection (ATCC, Rockville, Maryland) as representative of mesenchymal cells. These cells were grown in Minimal Essential Medium (MEM) supplemented with 10% fetal bovine serum (FBS), 1% L-glutamine, and 2X concentration of Penicillin-Streptomycin-Neomycin. Human foreskin epithelial cells (HFEC) were isolated in our laboratories by digestion in dispase and trypsin and grown in Keratinocyte Serum Free Medium (K-SFM) without additives. These cells were used as representative of normal epithelium. All cell culture reagents were purchased from GIBCO, Grand Island, New York. Extraction dilution assays’ were performed by seeding cells in triplicate on six well culture dishes at a concentration of 2.5 x 105 cells/well and allowed to attach overnight. Anodized titanium or stainless steel bone plates (Synthes Maxillofacial, Paoli, Pa.) were steam sterilized and extracted in FBS (for CCG135) or K-SFM (for HFEC) at 37°C for 24 hours, and the cells were then treated with growth medium containing 5%, 0.5%, 0.05%, or 0% (control) extract for an additional 24 hours. After harvest by trypsin digestion, cells were counted in an automated cell counter. All experiments were performed in duplicate, and counts were analyzed by ANOVA to determine statistical significance. Our data revealed no growth effect of either titanium or stainless steel extracts on fibroblast-like cells, but a statistically significant growth enhancing effect of titanium extracts on normal human keratinocytes was evident. Stainless steel extracts did not exhibit this effect. While these findings do not suggest a mechanism, many metals are known to corrode, cross cell membranes, and alter cellular nutrient pathways when in contact with biological fluids.* We conclude that substances solubilized from titanium implants may contribute to increased epithelial cell growth. AAOMS
.
1991
OralAbstractSessionI: MaxillofacialReconstruction References Northrup, S.J.:Mammalian cellculture models, in van Recum, A. (ed): Handbook of Biomaterials Evaluation. New York, NY, Macmillaa, t986, pp 220-222 Lemons, J.E.: Corrosion and biodegradation. Ibid., p 111
Table 2. Pathologic Diagnosis
n
Squamous cell carcinoma Adenoid cystic carcinoma Ewing’s sarcoma Total
15 2 1 18
Supported by NYS Science and Technology Foundation
major myocutaneousand trapezius flaps have greater massesof tissueavailableand shouldbe considered. Marrdibutar ReconstnrctionWh A0 Platesin Thesepatientshad no secondarybonegraftingdue to -edMalignant Tumors the extensivesoft tissueresection,recurrenceof tumor, Philip J. Smith, DDS, Ring FaisalSpecialistHospital or the patient’s refusal to have further surgery. No and ResearchCentre,PO Box 3354,Riyadh 11211, patient hasexperiencedplate fractureto date although Kingdom of SaudiArabia (Douglass,J.B., Al-AIi, T.E.) this hasbeenreportedby others.Three patientshaveno A retrospective review of patients with advanced evidenceof diseaseto date, six patientshad recurrence malignanttumors,that underwentmandibularresection of the primary tumor with two havingmetastaticlesions and reconstructionusingA0 plates,at the Ring Faisal to the lung. There havebeen five deathsin this group Specialist Hospital and Research Centre was per- and three of the other patientswere lost in the followformed.The reconstructionof mandibulardefectsfollow- up. At the present time, we do not feel that bone ing resection of the mandible allows the patient to reconstruction in these patients is indicated unless adequatesoft tissuecoverageand hyperbaricoxygenis resumemastication,speech,andoral hygiene. Eighteen patients with malignancythat required a available.Due to the low long term survival,secondary mandibular resection with plate reconstruction from bone grafting should be consideredin only carefuhy 1983through 1989were reviewed.Patients agesat the selectedpatients. The use of mandibular reconstructionplates in patime of surgeryrangedfrom 17 to 90 years(x 53),with tients with advancedtumors is indicated.The flaps used an evensexdistribution. The resectionswere of 3 types to insulate the plates must have adequatemuscle and (Table 1). The majority of pathologic diagnoseswere tissue mass. squamouscell carcinoma(Table 2). All patientswith the diagnosisof squamouscell carcinomawere either stage three or stagefour. The long term survivalrate for these References patients is guarded. Radiotherapy was administered Castillo, M.H., et al: Effects of Radiotherapy on Mandibular post-operativelyto 14 of the patients. The Ewing’s Reconstruction Plates. State University of New York at Buffalo and sarcomapatient receivedchemotherapyand radiother- Rosewell Park Memorial Institute apypre-operativelywith no post-operativeradiotherapy. Klotch, D.W., Prein, J: Mandibular reconstruction using A0 plates. Nine patients were successfullyreconstructed.Nine Veterans Administration Hospital, Tampa, FL plateswere removedfor the followingreasons:threedue to infection, three due to extrusionseither intra or extra orally, and threewere removedbecauseof tumor recur- MicrovascuharRecorwtrudon of the rence. The possibility that post-surgicalradiotherapy oromandibular CompositeDefect may havean influenceon the viability of the tissuesin Akinobu Hattori, DDS, Dept. of OMS, Nara Medical the areaof the plate hasbeeninvestigated,and there is University,840Shijo-choNara-Kashihara634,Japan no evidenceto date that radiotherapycontributes to (Horiuchi, R., Kamibayashi,T., Sugimura,M.) plate loss. Two of the patientswith extrusionof the plates had Reconstructionof the oromandibularcompositedestemocleidomastoidflaps and one had a sternothyroid fect is one of the most challengingproceduresin oral flap. These flaps may not have enoughtissuemass to and maxillofacial surgery.The adventof microvascular insulate the plates against tissue contraction and the transferssuchasan osteocutaneous groin flap hasmade forces of mastication. Deltapectoral flaps, pectoralis significantadvancesin oromandibularcompositereconstruction. Table 1. This report presentsour experienceof ten patients, Surgical Resections n from 14 to 63 years of age, who have undergone oromandibularcompositereconstructionswith vascularHemi-mandrbulectomies 11 Partial mandibular resection 7 izedcompositetissuetransplantationssinceJuly 1987. Angle to angle resection 1 In seven patients who were immediately reconTotal 18 structedafter ablativesurgeryfor oral cancers,mandibMOMS
.
1991
69
Henny Fellowship and NIDR Grant DE
Titanium ExtractbEnhanceEpitheliul Cell Growth John H. Campbell, DDS, Orofacial Medicine Div., Head and Neck Center, Sisters of Charity Hospital, 2121 Main St, Buffalo, NY 14214 (Edsberg, L.) Metals in the form of wires, bone plates, or transmucosal implants are commonly used in reconstruction of congenital or acquired facial anomalies. One clinical problem often encountered with transmucosal implants is a hyperplastic tissue response adjacent to the implant. This investigation was undertaken to assess in vitro growth effects of stainless steel and titanium on human mesenchymal and epithelial cells to elucidate the etiology of these clinical findings. CCL-135, a human fibroblast-like lung cell culture, was acquired from the American Type Culture Collection (ATCC, Rockville, Maryland) as representative of mesenchymal cells. These cells were grown in Minimal Essential Medium (MEM) supplemented with 10% fetal bovine serum (FBS), 1% L-glutamine, and 2X concentration of Penicillin-Streptomycin-Neomycin. Human foreskin epithelial cells (HFEC) were isolated in our laboratories by digestion in dispase and trypsin and grown in Keratinocyte Serum Free Medium (K-SFM) without additives. These cells were used as representative of normal epithelium. All cell culture reagents were purchased from GIBCO, Grand Island, New York. Extraction dilution assays’ were performed by seeding cells in triplicate on six well culture dishes at a concentration of 2.5 x 105 cells/well and allowed to attach overnight. Anodized titanium or stainless steel bone plates (Synthes Maxillofacial, Paoli, Pa.) were steam sterilized and extracted in FBS (for CCG135) or K-SFM (for HFEC) at 37°C for 24 hours, and the cells were then treated with growth medium containing 5%, 0.5%, 0.05%, or 0% (control) extract for an additional 24 hours. After harvest by trypsin digestion, cells were counted in an automated cell counter. All experiments were performed in duplicate, and counts were analyzed by ANOVA to determine statistical significance. Our data revealed no growth effect of either titanium or stainless steel extracts on fibroblast-like cells, but a statistically significant growth enhancing effect of titanium extracts on normal human keratinocytes was evident. Stainless steel extracts did not exhibit this effect. While these findings do not suggest a mechanism, many metals are known to corrode, cross cell membranes, and alter cellular nutrient pathways when in contact with biological fluids.* We conclude that substances solubilized from titanium implants may contribute to increased epithelial cell growth. AAOMS
.
1991
OralAbstractSessionI: MaxillofacialReconstruction References Northrup, S.J.:Mammalian cellculture models, in van Recum, A. (ed): Handbook of Biomaterials Evaluation. New York, NY, Macmillaa, t986, pp 220-222 Lemons, J.E.: Corrosion and biodegradation. Ibid., p 111
Table 2. Pathologic Diagnosis
n
Squamous cell carcinoma Adenoid cystic carcinoma Ewing’s sarcoma Total
15 2 1 18
Supported by NYS Science and Technology Foundation
major myocutaneousand trapezius flaps have greater massesof tissueavailableand shouldbe considered. Marrdibutar ReconstnrctionWh A0 Platesin Thesepatientshad no secondarybonegraftingdue to -edMalignant Tumors the extensivesoft tissueresection,recurrenceof tumor, Philip J. Smith, DDS, Ring FaisalSpecialistHospital or the patient’s refusal to have further surgery. No and ResearchCentre,PO Box 3354,Riyadh 11211, patient hasexperiencedplate fractureto date although Kingdom of SaudiArabia (Douglass,J.B., Al-AIi, T.E.) this hasbeenreportedby others.Three patientshaveno A retrospective review of patients with advanced evidenceof diseaseto date, six patientshad recurrence malignanttumors,that underwentmandibularresection of the primary tumor with two havingmetastaticlesions and reconstructionusingA0 plates,at the Ring Faisal to the lung. There havebeen five deathsin this group Specialist Hospital and Research Centre was per- and three of the other patientswere lost in the followformed.The reconstructionof mandibulardefectsfollow- up. At the present time, we do not feel that bone ing resection of the mandible allows the patient to reconstruction in these patients is indicated unless adequatesoft tissuecoverageand hyperbaricoxygenis resumemastication,speech,andoral hygiene. Eighteen patients with malignancythat required a available.Due to the low long term survival,secondary mandibular resection with plate reconstruction from bone grafting should be consideredin only carefuhy 1983through 1989were reviewed.Patients agesat the selectedpatients. The use of mandibular reconstructionplates in patime of surgeryrangedfrom 17 to 90 years(x 53),with tients with advancedtumors is indicated.The flaps used an evensexdistribution. The resectionswere of 3 types to insulate the plates must have adequatemuscle and (Table 1). The majority of pathologic diagnoseswere tissue mass. squamouscell carcinoma(Table 2). All patientswith the diagnosisof squamouscell carcinomawere either stage three or stagefour. The long term survivalrate for these References patients is guarded. Radiotherapy was administered Castillo, M.H., et al: Effects of Radiotherapy on Mandibular post-operativelyto 14 of the patients. The Ewing’s Reconstruction Plates. State University of New York at Buffalo and sarcomapatient receivedchemotherapyand radiother- Rosewell Park Memorial Institute apypre-operativelywith no post-operativeradiotherapy. Klotch, D.W., Prein, J: Mandibular reconstruction using A0 plates. Nine patients were successfullyreconstructed.Nine Veterans Administration Hospital, Tampa, FL plateswere removedfor the followingreasons:threedue to infection, three due to extrusionseither intra or extra orally, and threewere removedbecauseof tumor recur- MicrovascuharRecorwtrudon of the rence. The possibility that post-surgicalradiotherapy oromandibular CompositeDefect may havean influenceon the viability of the tissuesin Akinobu Hattori, DDS, Dept. of OMS, Nara Medical the areaof the plate hasbeeninvestigated,and there is University,840Shijo-choNara-Kashihara634,Japan no evidenceto date that radiotherapycontributes to (Horiuchi, R., Kamibayashi,T., Sugimura,M.) plate loss. Two of the patientswith extrusionof the plates had Reconstructionof the oromandibularcompositedestemocleidomastoidflaps and one had a sternothyroid fect is one of the most challengingproceduresin oral flap. These flaps may not have enoughtissuemass to and maxillofacial surgery.The adventof microvascular insulate the plates against tissue contraction and the transferssuchasan osteocutaneous groin flap hasmade forces of mastication. Deltapectoral flaps, pectoralis significantadvancesin oromandibularcompositereconstruction. Table 1. This report presentsour experienceof ten patients, Surgical Resections n from 14 to 63 years of age, who have undergone oromandibularcompositereconstructionswith vascularHemi-mandrbulectomies 11 Partial mandibular resection 7 izedcompositetissuetransplantationssinceJuly 1987. Angle to angle resection 1 In seven patients who were immediately reconTotal 18 structedafter ablativesurgeryfor oral cancers,mandibMOMS
.
1991
69