Periodontium Regeneration and Development

Study Notes

Connective Tissue and Periodontal Cells

Connective tissue, PDL, bone, and cementum are derived from undifferentiated connective tissue cells.
These cells develop into fibroblasts, osteoblasts, and cementoblasts.

Regeneration of the Periodontium

Regeneration is a continuous physiologic process under normal conditions.
New cells and tissues are formed to replace mature and dead cells.
This process is termed "wear and tear repair".

Regeneration during Destructive Periodontal Disease

Gingival and periodontal diseases are chronic inflammatory conditions that involve healing processes.
Bacteria and bacterial products prevent healing from proceeding to completion.
When bacterial plaque is removed, the inherent regenerative capacity of tissues is established.

Repair and Healing

Repair is the restoration of the continuity of the diseased marginal gingiva.
It involves the reestablishment of a normal gingival sulcus at the same level as the base of a preexisting pocket.
This process is called "healing by scar".
Bone loss is arrested with mobilization of epithelial and connective tissue cells into the damaged area.

New Attachment and Reattachment

New attachment is the embedding of new PDL fibers into new cementum and attachment of epithelium to a tooth surface.
Reattachment is not the correct term, as new fibers are formed and attach to new cementum.
Reattachment refers to repair in areas of the root not previously exposed to pockets.

Animal Studies

Animal studies can be used to evaluate periodontal regeneration and new attachment.
This method involves extraction of the examined tooth with its periodontium after successful treatment.

Reconstructive Surgical Techniques

Reconstructive techniques can be subdivided into three major therapeutic approaches:
- Non-bone graft-associated
- Graft-associated
- Biologic mediator-associated
Clinicians often combine these approaches in clinical practice.

Non-Graft-Associated Reconstructive Procedures

These procedures aim to achieve new attachment or periodontal bone regeneration.
GTR (Guided Tissue Regeneration) is the main procedure used in clinical practice.
Laser-assisted new attachment procedure (LANAP) may also result in new attachment and regeneration.

Guided Tissue Regeneration (GTR)

GTR is used to prevent epithelial migration along the cemental wall of the pocket.
It maintains space for clot stabilization.
GTR involves placing barriers (membranes) to cover the bone and periodontal ligament, excluding the epithelium and gingival connective tissue.

Principles of Non-Graft New Attachment

Complete removal of all irritants with or without exposure of the area with a flap.
Occlusal adjustment may be indicated if there is trauma from occlusion.
The possible outcomes of therapy depend on which cells populate the area first:
- Epithelial cells: long junctional epithelium
- Gingival connective tissue cells: fibers parallel to the tooth surface and remodeling of the alveolar bone
- Bone cells: root resorption and ankylosis
- Periodontal ligament cells: new formation of cementum and PDL (new attachment)

Evaluation of New Attachment and Bone Regeneration

Clinical methods: comparison of pre and post treatment records of pocket probing, attachment level, gingival indices, and alveolar bone level.
Radiographic methods: standardized technique is needed for reproducible positioning of the film and the tube.
Surgical re-entry: evaluation can be performed by taking repeated impressions.
Histologic methods: type of attachment can be determined only by histologic analysis of tissue blocks obtained from the healed area.

Description

This quiz covers the development and regeneration of periodontal tissues, including connective tissue, PDL, bone, and cementum. It also explores the regeneration process under normal conditions and during destructive periodontal disease.