Titanium Implants and Surface Properties

Implantlogy Program (Basic Implantology) - Semester 2

• Course taught by Ass.Prof.Dr. Marwa Mohammed Tawfiq
• Associate professor of Oral medicine and periodontology
• Beni-suef university

Periodontal Regeneration

• The reproduction or reconstitution of lost or injured parts of the tooth supporting structures to restore form and function
• The process involves restoring lost tissues during periodontal disease, including structures like alveolar bone, cementum, and periodontal ligament
• It's a complex process with diseased periodontium, cells, scaffolds, and signaling molecules requiring blood supply
• Periodontal repair involves healing by long junctional epithelium without completely restoring architectural function or form.

Regenerative Periodontal Therapy

• Aims to reproduce or reconstitute lost or injured parts of the tooth supporting structures
• This process is critical to restoring the form and function of the lost structures, supporting tissues during periodontal disease
• Regrowth of cementum, alveolar bone and periodontal ligament is part of treating periodontal disease

Reattachment

• The reunion of epithelial and connective tissue with a root surface surgically or mechanically separated
• New attachment may involve epithelial adhesion or connective tissue adaptation or include new cementum
• This typically happens when the attachment has been lost due to disease progression

Classification of Periodontal Pockets

• Gingival sulcus (shallow pocket)
• Free gingiva
• Attached gingiva
• Free gingival groove
• Mucogingival junction
• Alveolar mucosa
• Gingival pocket
• Suprabony periodontal pocket
• Intrabony periodontal pocket
• Classification based on the position of the pocket base relative to the underlying bone
• 3-wall, 2-wall, combination, and 1-wall defects

Types of Periodontal Pockets

• Pockets can involve 1, 2, or more tooth surfaces
• They can be different depths and types on the same tooth surface
• Pockets can be spiral, originating on one tooth surface and twisting around to involve multiple surfaces
• This is most often the case in furcation areas

Horizontal vs. Intrabony Bone Loss

• Horizontal bone loss occurs when the bone loss is parallel to a line drawn from the cementoenamel junction (CEJ) of one tooth to the CEJ of an adjacent tooth
• This is a common pattern of bone loss seen in periodontal disease
• Intrabony pockets are pockets where the base of the pocket lies below the level of the adjacent alveolar bone
• This is indicated by more rapid bone resorption

Healing of Three-Wall Intrabony Defects

• Blood clot fills the defect immediately after surgery
• The clot and surrounding tissues contain growth factors, proteins, and molecules necessary for normal wound healing
• Organization of the clot occurs several days later with increased blood vessels and granulation tissue formation
• Epithelial cells from the wound margins begin to migrate across the clot
• Osteogenic activity appears around the developing capillaries by the 21st day
• The socket is filled with bone by 2 months with continuing calcification
• Bone fill is visible on radiographs by 6 months

Preparation for Regeneration and Attachment

• Three critical areas of treatment for regeneration and attachment:
• Granulation tissue of the defect
• The root surface
• The underlying bone
• Removal of bacterial deposits, calculus, and endotoxins on the cementum surface
• Demineralization of the root surface to expose dentin collagen
• Decortification involving the formation of small holes in the bone

Periodontal Regeneration Procedures

• Grafting procedures
• Guided tissue regeneration (GTR)
• Root conditioning and biomodification
• Biologic mediators for periodontal regeneration (e.g., Emdogain)
• Combination of the above procedures

Grafting Materials

• Osteoinductive: induce bone formation in surrounding soft tissues through growth factors
• Osteoconductive: provide a scaffold for the formation of new bone
• Osteoneutral: serve only as space fillers
• Different types of grafts based on origin (autogenous, allogenic, xenogenic, alloplastic) and substitutes (e.g., bone substitutes)

Selection of Graft Material Criteria

• Osteoinductive potential
• Osteoconductivity
• Accessibility
• Availability
• Safety and biological compatibility
• No risk of disease transmission (e.g., AIDS, viruses)

Guided Tissue Regeneration (GTR)

• Aims to regenerate lost periodontal structures (i.e., cementum, periodontal ligament, and alveolar bone)
• Involves cell and tissue repopulation of periodontal wounds
• Repair involving connective tissue adhesion and long junctional epithelium formation

Barriers in GTR

• Exclusion of epithelial and gingival connective tissue cells from the periodontal defect
• Membranes maintain space between defect and barrier for regenerative cells from periodontal ligament
• Barriers stabilize clots

Indications for GTR

• Intra-bony defects
• Furcations
• Gingival recession
• Alveolar ridge augmentation

Biocompatible Barrier Membranes

• Should be biocompatible to avoid immune response
• Material should act as a barrier to prevent undesirable cell types
• Must create space for tissue ingrowth from the periodontal ligament to the root surface

Technique for GTR

• Surgical initiations : Sulcular incisions
• Removal of all granulation tissue
• Debridement of root surfaces
• Shape membrane to cover defect, extending at least 3mm beyond defect margins
• Fixation with sutures and chlorhexidine gluconate rinse (at least 4 weeks)
• Systemic antibiotics during and after surgery
• Removal of non-resorbable membranes after 4-6 weeks

Causes of GTR Failure

• Surgical technique (improper incision placement, excessive loss of marginal tissue, trauma, etc)
• Post-surgical factors (plaque recolonization, mechanical insult, loss of wound stability, etc)
• Barrier-dependent factors (inadequate barrier adaptation, non-sterile technique, premature barrier exposure, etc)

Contraindications for GTR

• Class II furcations
• Horizontal bone loss
• Patient's health, compliance, and tooth mobility
• Any medication or conditions that might hinder proper healing

Types of Barrier Membranes

• Non-absorbable: Last longer but require a second procedure for removal
• Bio-absorbable: Avoids second surgery, but absorption can take weeks to months

Root Surface Conditioning Materials

• Tetracycline
• Citric acid

Biological Mediators for Periodontal Regeneration

• Growth and differentiation factors (e.g., PDGF, IGF, FGF)
• Mediators of bone metabolism (e.g., BMPs)
• Attachment factors (e.g., fibronectin)
• Extracellular matrix proteins (e.g., enamel matrix proteins)

Bone Regeneration in Implant Dentistry

• Dental implants are widely used for missing teeth restoration
• The need to regenerate alveolar bone in certain situations for implant success
• Bone regeneration procedures can improve stability, predictability, and long-term success of implant treatments

Factors Affecting GBR outcomes

• Patient-related: Compliance, history of periodontitis, smoking
• Biomaterials-related: Barrier/graft properties, clinical handling, resorption pattern, bioactivity
• Surgery-related: Healing protocol, surgical complications
• Implant-related: Implant surface
• Prosthetic-related: Loading protocol, abutment characteristics

Principles of GTR

• Aiming at regeneration of lost periodontal structures (cementum, PDL, and alveolar bone)
• Selective repopulation of periodontal wounds

The Biology of Bone Regeneration

• Cell recruitment: recruitment of osteoprogenitor cells for the start of the process
• Matrix deposition: blood clot provides a scaffolding for the growth of cells through the wound area
• Signaling pathways: signaling pathways, such as BMP and VEGF, regulate the differentiation of osteoprogenitor cells

The Impact of Surgery-Related Factors

• Submerged vs Non-submerged healing protocols
• Surgical complications: soft tissue dehiscence, membrane exposure, infections, leading to decreased quality and stability

Molecular Mechanisms of Bone Formation

• Hydrophilic and moderately rough surfaces promote early bone formation and favorable immune response
• Complex signaling pathways regulate cell proliferation, osteogenesis (bone formation) and angiogenesis to achieve bone regeneration

The Impact of Biomaterials

• Importance of barrier membranes (and bone grafts / substitutes)
• Properties of various materials: Their impact on bone regeneration, space maintenance, and stability of the procedure

The Impact of Prosthetic Factors

• Implant loading timing (immediate, early, conventional)
• Abutment characteristics: Design and properties influence peri-implant tissue stability and maintenance of regenerated bone

Patient-Related Factors

• Periodontitis history, systemic conditions (diabetes, osteoporosis), smoking

History of Periodontitis, Compliance, and Oral Hygiene

• Thorough assessment of oral conditions required
• Development of an individual oral healthcare plan
• Coaching patients on proper oral hygiene
• Professional plaque removal

Systemic Conditions and Smoking

• Underlying medical conditions can negatively affect bone and soft tissue healing during regeneration
• Smoking is detrimental to wound healing, increasing the risk of complications and implant failure

Diabetes Mellitus

• Diabetes is linked to complications (bone disease/osteopathy) during implant placement, potentially affecting peri-implant bone formation and mineralization
• This may also lead to negative impacts on bone regeneration quality.

Considerations in Osteoporosis

• Osteoporosis affects bone quality in the jaw and may correlate with reduced bone density/increased cortical porosity
• Patients with osteoporosis are at higher risk for complications during implant procedures, so the clinician should extend healing time
• A diagnosis of osteopenia or osteoporosis may not prevent implant placement today

Risks of Peri-Implantitis

• Prevalence of peri-implantitis (inflammation around implants) may vary based on initial implant location
• It is important to monitor peri-implant diseases for both pristine and regenerated sites

Future Directions in Bone Regeneration

• Tissue engineering approaches integrating cells, biomaterials, and signaling pathways can revolutionize treatment methods
• Personalized approaches will utilize proteomics and transcriptomics to create customized treatments, improving outcomes,

Considerations for GBR Success

• Space maintenance is crucial
• Bioactivity, stability, and appropriate grafting materials play a role in GBR outcomes
• Clinical success requires monitoring
• A variety of strategies support ideal stability in GBR outcomes

References

• Includes listed authors, publication titles, and publication years. (Note: these need to be filled using the supplied references)

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