Journal of Oral Implantology June 2014 - (Page 229)

EDITORIAL Controlled Early Inflammation and Bone Healing- Potential New Treatments I n dental school, we were taught the scientific principle ''inflammation is necessary for healing''. This principle needs to be updated due to the further characterization of the role inflammation plays in the healing process. Early bone healing occurs via specific cellular signaling events: (i) proinflammatory, (ii) antiinflammatory, (iii) proangiogenic, and (iv) osteogenic.1 Research has increased our understanding of the connection between the immune system and bone healing.2-6 The significance of controlling the immediate inflammatory response for successful bone formation has been confirmed.7 When an osteotomy is performed, multiple proinflammatory cytokines (1st signaling event) are stimulated, such as interleukin (IL)-1a, IL-1b, IL-6, and tumor necrosis factor alpha (TNF-a). Einhorn et al.8,9 identified this early inflammatory cytokine expression profile in 2002 and 2003; however, the down-regulation or modulation of cytokine expression was not considered until more recently. Controlling cytokine expression (inflammation) can help create the ideal environment for healing and bone formation. If the cytokine expression is not in a proper balance, compromised bone healing is observed. 1; for example, excessive concentrations and time-exposure of TNF-a can lead to delayed bone formation.10 Franchimont et al.11 controlled the level of TNF-a by increasing the release of the anti-inflammatory cytokine IL-10 (2nd signaling event), thus creating a positive environmental impact at the surgical site. IL-6 has been shown to have a bi-phasic pro- or anti-inflammatory concentration-dependent effect on bone healing.12,13 Other events necessary for healing include the migration to, and accumulation of, stem and osteoprogenitor cells at the surgical site. The accumulation and activation of these osteogenic cells (4th signaling event) are dependent upon angiogenesis (3rd signaling event). Proinflammatory cytokines in DOI: 10.1563/AAID-JOI-D-14-Editorial.4003 the surgical site can inhibit stem cell differentiation and therefore bone formation.7 Controlling inflammation is thought to have a positive effect on all signaling events. Modulating the immune response during early bone formation may provide a favorable environment for improved predictability of bone grafting procedures. Schmidt-Bleek et al.1 concluded: ''The modulation of the immune response is a promising approach to improve bone regeneration.'' This greater understanding of the interconnection between the immune system and bone healing may well play a significant role in the future of implant dentistry. As clinicians, our responsibility is to provide efficient and predictable treatments with minimal discomfort; modulating the inflammatory response may be instrumental in meeting these treatment goals. Strategies to control the immune response will undoubtedly be forthcoming and play an important role in our clinical practices. James L. Rutkowski, DMD, PhD Editor-in-Chief REFERENCES 1. Schmidt-Bleek K, Petersen A, Dienelt A, Schwarz C, Duda GN. Initiation and early control of tissue regeneration - bone healing as a model system for tissue regeneration. Expert Opin Biol Ther. 2014;14:247-259. 2. Takayanagi H. Osteoimmunology: shared mechanisms and crosstalk between the immune and bone systems. Nat Rev Immunol. 2007;7:292-304. 3. Lorenzo J, Choi Y, Horowitz M, Takayanagi H, eds. Osteoimmunology. 1st ed. London: Elsevier; 2011. 4. Lorenzo J, Horowitz M, Choi Y. Osteoimmunology: interactions of the bone and immune system. Endocr Rev. 2008; 29:403-440. 5. Walsh MC, Kim N, Kadono Y, et al. Osteoimmunology: interplay between the immune system and bone metabolism. Annu Rev Immunol. 2006;24:33-63. 6. Nakashima T, Takayanagi H. Osteoimmunology: crosstalk between the immune and bone systems. J Clin Immunol. 2009;29: 555-567. Journal of Oral Implantology 229

Table of Contents for the Digital Edition of Journal of Oral Implantology June 2014

Controlled Early Inflammation and Bone Healing—Potential New Treatments
Zygomatic Implants: The Impact of Zygoma Bone Support on Biomechanics
A Comparative Study on Microgap of Premade Abutments and Abutments Cast in Base Metal Alloys
Topical Simvastatin Improves the Pro-Angiogenic and Pro-Osteogenic Properties of Bioglass Putty in the Rat Calvaria Critical-Size Model
Assessment of the Correlation Between Insertion Torque and Resonance Frequency Analysis of Implants Placed in Bone Tissue of Different Densities
Benefits of Rehabilitation With Implants in Masticatory Function: Is Patient Perception of Change in Accordance With the Real Improvement?
A Method for Fabrication of Implant-Supported Fixed Partial Dentures
Safe Sinus Lift: Use of Acrylic Stone Trimmer to Avoid Sinus Lining Perforation
The Effects of Sinus Membrane Pathology on Bone Augmentation and Procedural Outcome Using Minimal Invasive Antral Membrane Balloon Elevation
Cellular Responses to Metal Ions Released From Implants
A Two-Stage Surgical Approach to the Treatment of Severe Peri-Implant Defect: A 30-Month Clinical Follow-Up Report
Eight-Year Follow-Up of a Fixed-Detachable Maxillary Prosthesis Utilizing an Attachment System: Clinical Protocol for Individuals With Skeletal Class III Malocclusions
Active Implant Peri-Apical Lesion: A Case Report Treated Via Guided Bone Regeneration With a 5-year Clinical and Radiographic Follow-up
Flapless Implant Placement: A Case Report
Active Implant Periapical Lesions Leading to Implant Failure: Two Case Reports
A Review of Platelet Derived Growth Factor Playing Pivotal Role in Bone Regeneration
LETTER TO THE EDITOR
REVIEW OF CURRENT LITERATURE

Journal of Oral Implantology June 2014