2025 Open Apex II

Concept of the Open Apex

  • Open Apex – found in developing roots of immature teeth
  • Normal in the absence of pulp or periradicular disease
  • If pulp necrosis occurs before root formation is complete: dentin formation ceases and root growth is arrested
  • Open apex represents a key challenge for achieving a reliable apical seal with conventional obturation unless barrier formation is achieved

Definitions and Key Concepts

  • Apexification (Root-End Closure)
    • Also called Apexification
    • Defined as the process of creating an environment within the root canal and periapical tissues after pulpal death that allows a calcific barrier to form across the open apex
  • Apexogenesis (Vital P pulp Therapy)
    • Vital pulp therapy aimed at continued physiological root development in teeth with immature roots
  • Regenerative Endodontics (Regendo)
    • Regenerative procedures aiming to restore pulpal tissue and continued root development
  • Root Canal Therapy (RCT)
    • Conventional treatment for necrotic or irreversibly inflamed pulpal tissue in teeth with closed apex

Indications and Contraindications for Root-End Closure and Vital Pulp Therapy

  • Indications for Root-End Closure / Apexification
    • Restorable immature tooth with pulp necrosis
    • Irreversible Pulpitis with Necrotic Pulp
  • Contraindications for Root-End Closure (Apexification) in general
    • All vertical root fractures and most horizontal root fractures
    • Replacement resorption (ankylosis)
    • Very short roots
    • Marginal periodontal breakdown
    • Vital pulps (in context of apexification; these cases may be directed toward Vital Pulp Therapy instead)
  • Vital Pulp Therapy indications include Apexogenesis, Pulp Capping, and Pulpotomy when the tooth is a candidate for continued root development

Apexification with Calcium Hydroxide (Ca(OH)₂)

  • Three general phases
    • Access
    • Instrumentation
    • Placement of Ca(OH)₂ intracanal dressing and periodic replacement
  • Dressing frequency
    • Every 3−6extmonths3-6 ext{ months} until an apical bone barrier has developed
  • Definition emphasis
    • Induction of apical calcific barrier (bone) in immature teeth with incomplete root formation when the pulp is necrotic (non-vital)
  • Process description
    • Thorough chemomechanical debridement of the root canal space
    • Placement of Ca(OH)₂ paste as an intracanal dressing

Apexification with Calcium Hydroxide: Treatment Evaluation & Prognosis

  • Treatment evaluation schedule
    • First recall: 4−6extweeks4-6 ext{ weeks}; radiographic evaluation; indications for tooth re-entry
    • Then recall in 3−6extmonths3-6 ext{ months} thereafter
    • If apex is still open, replace Ca(OH)₂ and re-enter after another 3−6extmonths3-6 ext{ months}
    • If calcific barrier forms, proceed with obturation
  • Long-term follow-up
    • At 1extyear1 ext{ year} follow-up, evaluate radiographically for resolution/bony fill of periapical radiolucency and proceed with obturation
  • Prognosis
    • Generally good success rate
    • Very immature teeth with thin dentin walls are at high risk of root fracture
    • Incidence of root fracture depends on the stage of root development
    • Barrier formation occurs more rapidly when the apical opening diameter is less wide
  • Outcome assessment criteria (for apexification via Ca(OH)₂)
    • Absence of signs or symptoms of pulpal and/or periapical disease
    • Presence of calcific barrier across the apex as demonstrated by radiographs and tactile probing with a file upon re-entry
  • Determinants of failed treatment
    • Primary cause: bacterial contamination
    • Common source: loss of coronal seal or inadequate debridement

Apexification with Mineral Trioxide Aggregate (MTA)

  • Rationale
    • Create an instant apical barrier with a biocompatible material (bioceramics like MTA)
  • Three general phases
    • Access
    • Instrumentation
    • Placement of Ca(OH)₂ for disinfection, followed by placement of MTA across the open apex to create an instant apical barrier
  • apical barrier creation
    • Artificial barrier across open apex in teeth with immature root formation using bioceramics (e.g., MTA)
  • Process steps for MTA apexification
    • Local anesthesia and rubber dam isolation
    • Conventional access with a high-speed burr for canal debridement
    • Place Ca(OH)₂ paste for one week to disinfect the canal system
    • Mix MTA with sterile water and carry into the canal
    • Condense MTA to the apical extent to create a 3−4extmm3-4 ext{ mm} barrier
    • Verify MTA placement radiographically; if unsatisfactory, rinse and repeat
    • Place a moist cotton pellet in the canal to ensure proper MTA setting
  • Clinical practice notes
    • MTA-based apexification tends to shorten treatment time compared to long-term Ca(OH)₂ therapy
  • Clinical examples
    • Demonstrated in cases presented by colleagues (e.g., Drs. Berrios, Brennan) in the course materials

Comparison: Ca(OH)₂ Apexification vs MTA Apical Barrier

  • Clinical outcomes
    • Similar clinical success rates for both approaches
  • Advantages of MTA apexification
    • Reduced treatment time
    • More predictable apical barrier formation

Regenerative Endodontics and Current Trends

  • Current trends (as of 2026)
    • Pulpal tissue engineering
    • Stem cell research
    • Regenerative endodontics
    • Questioning whether apexification will become obsolete with regenerative approaches
  • Paradigm shifts in managing immature teeth with periradicular disease
    • Shifting from apexification to apexogenesis where feasible
  • Key literature pointers
    • Ling-Huey Chueh & George T-J Huang (regenerative approach in immature teeth with periradicular periodontitis or abscess)

Indications & Contraindications: Vital Pulp Therapy vs Apexogenesis / Apexification / Regenerative Endodontics

  • Vital Pulp Therapy indications include Apexogenesis, Pulp Capping, Pulpotomy
  • Apexification indications include Root-end Closure when apex is open and pulp necrosis
  • Regenerative procedures considered when aiming for continued root development in immature teeth with necrotic/pulpally involved tissue
  • Diagnostic considerations influence case selection (see below)

Case Selection Decision Tree for Incompletely Formed Roots

  • Decision pathways (summary from the slide/tree)
    • Irreversible Pulpitis / Necrotic Pulp
    • Closed apex → Root canal therapy
    • Open apex → Vital Pulp Therapy (Pulp Capping or Pulpotomy) or Root-end Closure with Ca(OH)₂ or MTA or Regenerative Endodontics
    • Reversible Pulpitis
    • Vital Pulp Therapy (Pulp Capping or Pulpotomy)
    • Cases with open/apical conditions may consider Regenerative Endodontics or RCT with obturation depending on diagnosis and vitality
  • Emphasis in decision-making
    • Always weigh tooth restorability, microbial control, and potential for continued tooth development

Diagnostic Considerations and Terminology: Pulpal Disease

  • Diagnostic problem
    • The term “irreversible pulpitis” implies an outcome of pulp extirpation; however, modern evidence shows potential for Vital Pulp Therapy in some cases labeled as irreversible pulpitis
  • Evidence base
    • Systematic review (Cushley et al., J Dent 2019) shows similar success rates for Vital Pulp Therapy (VPT) and non-surgical root canal therapy (NSRCT) for certain irreversible pulpitis cases
  • Terminology evolution
    • Some authors suggest using a more generic term “pulpitis” to avoid implying non-viability of treatment
  • Future trends in diagnosis
    • The nomenclature in pulpal and periapical disease is evolving
    • European Society of Endodontology (ESE) S3-level guidelines advocate precise terminology and outcome-focused diagnostics
  • Practical implications
    • An accurate diagnostic terminology and appreciation of core outcomes improve treatment planning and success rates

Case Selection, Outcome, and Follow-Up: What Counts as Success or Failure

  • Criteria for success (apexification with Ca(OH)₂ or MTA)
    • Absence of signs or symptoms of pulpal and/or periapical disease
    • Presence (or radiographic evidence) of a calcific barrier across the apex
    • Confirmed by radiographs and tactile probing on re-entry if needed
  • Criteria for failure
    • Persistent symptoms, persistent radiolucency, lack of barrier formation, or failure of the apical barrier
  • Follow-up considerations
    • Regular recalls to monitor healing, barrier formation, and restoration integrity

Practical Considerations and Clinical Examples

  • Importance of coronal seal integrity
    • Loss of coronal seal is a common source of bacterial contamination leading to treatment failure
  • Coronal restoration and prevention of microleakage
    • Timely and durable coronal restoration following apexification or regenerative treatment is critical
  • Clinician experience and material choice
    • Choice between Ca(OH)₂ and MTA may depend on case specifics, anatomy, patient factors, and desired treatment duration

Current and Emerging Trends: 2024–2026 Outlook

  • Regenerative endodontics as a growing field
    • Emphasis on stem cells, signaling molecules, and scaffolds to support dentin/pulp regeneration
  • Pulpal tissue engineering and stem cell research
    • Potential to re-establish vitality and continued root formation in immature teeth with necrotic pulps
  • The shift away from apexification toward apexogenesis and regenerative approaches when feasible
  • Clinical decision-making remains nuanced
    • Not all cases are candidates for Regenerative Endodontics; proper case selection remains essential

Concluding Thoughts

  • The management of incompletely formed roots requires a nuanced approach balancing biology, mechanics, and patient-specific factors
  • Current trends suggest a move toward vitality-preserving and regenerative strategies, but traditional apexification with Ca(OH)₂ or MTA remains relevant and effective in appropriate cases
  • Ongoing refinement of diagnostic terminology and outcomes will support better, more consistent treatment planning

Appendix: Key Terms and Formulas

  • ext{Ca(OH)}_2
    ightarrow ext{calcium hydroxide}, commonly used as an intracanal medicament for disinfection
  • 3−6extmonths3-6 ext{ months}, recall interval for Ca(OH)₂ apexification dressing
  • 4−6extweeks4-6 ext{ weeks}, initial recall after Ca(OH)₂ placement
  • 3−4extmm3-4 ext{ mm}, thickness of MTA apical barrier
  • 1extyear1 ext{ year}, follow-up interval to assess healing and plan obturation
  • extMTAext{MTA}, mineral trioxide aggregate; a commonly used bioceramic for apical barriers
  • extBioceramicsext{Bioceramics}, biocompatible materials used for regenerative and barrier formation

Sources and Acknowledgments

  • Content adapted from Nadia Chugal’s lecture materials (Endodontics, UCLA) and related updates on apexogenesis, apexification, regenerative endodontics, and current trends in pulpal diagnosis and treatment
  • References cited within the course materials include reviews and guidelines on pulpal and periapical diagnosis and treatment planning