Crown Lengthening

Table of Contents

1. Definition
2. Objectives
3. Indications
4. Contraindications
5. Preoperative assessment
6. Techniques
7. Surgical procedure
8. Postoperative care
9. Complications
10. Conclusion

1. Definition

• Functional/restorative reasons: to expose subgingival caries, fracture margin, or restoration margin.
• Aesthetic reasons: to correct short-looking teeth, altered passive eruption, gingival asymmetry, or excessive gingival display.

2. Objectives

• Expose adequate tooth structure for restoration.
• Obtain retention and resistance form for a crown.
• Establish an adequate ferrule effect in endodontically treated teeth.
• Permit isolation during restorative treatment.
• Place restoration margins without invading periodontal soft tissues.
• Correct gingival contour and improve smile aesthetics.
• Facilitate plaque control and maintenance of periodontal health.

3. Indications

4. Contraindications

• Tooth with hopeless prognosis or insufficient remaining root length.
• Unfavourable crown-root ratio after surgery.
• Advanced mobility or severe periodontal bone loss.
• Furcation involvement likely to be exposed after osseous resection.
• Inadequate attached or keratinized gingiva.
• Poor plaque control or active periodontal inflammation.
• High caries activity not controlled.
• Aesthetic zone where postoperative recession or long clinical crown would be unacceptable.
• Medical conditions that preclude elective periodontal surgery, unless appropriately controlled.
• Inability of patient to maintain oral hygiene or attend follow-up.

5. Preoperative Assessment

• Assess plaque and gingival inflammation.
• Measure probing depth and gingival margin level.
• Determine width of keratinized tissue.
• Evaluate tooth mobility, furcation, crown-root ratio, and smile line.
• Identify the desired final restorative margin.

• Periapical radiograph to assess:
  • Root length and morphology
  • Alveolar bone height
  • Furcation anatomy
  • Periapical status
  • Crown-root ratio after anticipated bone removal

6. Techniques

7. Surgical Procedure: Apically Positioned Flap with Osseous Resection

1. Phase I therapy
   Complete scaling, plaque-control instruction, and control inflammation before surgery.
2. Local anaesthesia and marking
   Mark the desired new gingival margin after diagnostic assessment.
3. Incision
   Perform internal bevel incision followed by crevicular incision. Remove the gingival collar where necessary.
4. Flap reflection
   Elevate a full-thickness mucoperiosteal flap to expose alveolar bone and root surfaces.
5. Debridement
   Remove granulation tissue and thoroughly debride root surfaces.
6. Osseous resection and recontouring
   • Osteoplasty: reshaping of non-supporting bone.
   • Ostectomy: removal of supporting bone.
     Bone is reduced to create adequate space for soft-tissue attachment and to establish physiologic bony contour.
7. Apical positioning of flap
   Reposition the flap apically at the planned level.
8. Suturing
   Secure the flap with interrupted or sling sutures. A periodontal dressing may be used when indicated.

8. Postoperative Care

• Analgesics as required.
• Chlorhexidine mouth rinse may be prescribed for short-term chemical plaque control.
• Avoid brushing the operated area initially; maintain hygiene elsewhere.
• Soft diet and avoidance of trauma to surgical site.
• Review after approximately 7 to 14 days for suture removal.
• Regular periodontal maintenance and reassessment of tissue healing.
• Definitive restoration should generally be delayed until soft tissues have stabilized, especially in the aesthetic zone. Premature restoration can be affected by coronal rebound of the gingival margin.

9. Complications

• Postoperative pain, swelling, and bleeding.
• Gingival recession and root sensitivity.
• Poor aesthetic outcome due to elongated teeth or asymmetrical gingival margins.
• Loss of interdental papilla or black triangles.
• Furcation exposure.
• Unfavourable crown-root ratio or increased tooth mobility.
• Delayed healing or infection.
• Re-growth or coronal migration of gingiva.
• Violation of supracrestal tissue attachment if insufficient bone is removed, resulting in chronic inflammation, pocketing, recession, or recurrent loss of attachment.

10. Conclusion

Guided Endodontics

Table of Contents

1. Introduction and definition
2. Need for guided endodontics
3. Principles
4. Classification
5. Static guided endodontics
6. Dynamic navigation-guided endodontics
7. Digital workflow
8. Clinical applications
9. Indications
10. Contraindications and limitations
11. Advantages
12. Disadvantages
13. Static versus dynamic guidance
14. Guided endodontic microsurgery
15. Errors, complications, and their prevention
16. Evidence and future directions
17. Conclusion

1. Introduction and Definition

2. Need for Guided Endodontics

• Difficulty in identifying calcified canal orifices.
• Unnecessary removal of coronal and radicular dentine.
• Cervical, lateral, or furcal perforation.
• Instrument separation.
• Missed canals.
• Prolonged chairside time.
• Failure to establish a glide path.
• Weakened tooth structure and increased risk of vertical root fracture.
• Higher dependence on operator experience.

3. Principles of Guided Endodontics

1. Cone-beam computed tomography (CBCT)
   Provides three-dimensional information on root anatomy, canal pathway, calcification, periapical lesion, and surrounding structures.
2. Surface scan
   An intraoral scan or scan of a stone cast records tooth surfaces and soft tissues.
3. Digital superimposition
   CBCT data and surface scan data are merged using planning software.
4. Virtual planning
   The clinician plans the entry point, angulation, diameter, and depth of the drill pathway toward the target canal or surgical site.
5. Guidance during treatment
   This is delivered using:
   • A static, 3D-printed guide, or
   • A dynamic navigation system with optical tracking and real-time feedback.

4. Classification

A. According to method of guidance

1. Static guided endodontics
2. Dynamic navigation-guided endodontics

B. According to clinical application

1. Guided access cavity preparation.
2. Guided location of calcified canals.
3. Guided fibre-post removal.
4. Guided endodontic retreatment.
5. Guided apical surgery or endodontic microsurgery.
6. Guided management of teeth with developmental anomalies.
7. Guided treatment of dens invaginatus, dens evaginatus, and rotated teeth.
8. Guided autotransplantation-related endodontic procedures.

5. Static Guided Endodontics

Definition

Components

• CBCT scan
• Intraoral scan or scanned cast
• Planning software
• Virtual drill pathway
• 3D-printed guide/template
• Metallic sleeve, where used
• Long-shank bur or drill of planned diameter
• Rubber dam isolation and magnification

Principle

Types of Static Guides

1. Conventional external guide
   • Covers occlusal/incisal surfaces of neighbouring teeth.
   • Usually includes a metal sleeve.
2. Sleeveless guide
   • Does not use a metal sleeve.
   • Can improve visibility and permit more conservative access.
3. Intracoronal guide
   • Designed within an existing restoration or coronal structure.
   • Useful where mouth opening or interocclusal space is limited.
4. Microguided endodontics
   • Uses small-diameter drills and refined guides for conservative canal location, particularly in narrow roots such as mandibular incisors.

Static Guided Endodontic Workflow

Step 1: Case selection

Step 2: CBCT examination

• Canal remnant
• Extent of pulp canal obliteration
• Root curvature
• Root thickness
• Periapical pathology
• Relationship to adjacent roots and anatomical structures

Step 3: Surface scanning

Step 4: Image matching

Step 5: Virtual access planning

• Entry point
• Drill diameter
• Access angulation
• Planned depth
• Canal target point
• Safety distance from external root surface

Step 6: Template design and printing

Step 7: Clinical verification

• Check complete seating and stability of guide.
• Confirm correct orientation.
• Ensure rubber dam isolation.
• Verify drill length and stopper position.

Step 8: Guided drilling

Step 9: Canal negotiation

• Confirm canal patency using small hand files.
• Establish glide path.
• Continue cleaning, shaping, disinfection, and obturation by conventional endodontic principles.

6. Dynamic Navigation-Guided Endodontics

Definition

Components

• CBCT data
• Navigation software
• Optical tracking camera
• Patient tracking marker or reference frame
• Handpiece/drill tracking device
• Computer monitor
• Calibration system

Principle

• The patient's CBCT anatomy
• The actual position of the patient
• The position of the handpiece and bur

Workflow

1. Obtain CBCT scan.
2. Upload CBCT data into navigation software.
3. Plan canal access or surgical target virtually.
4. Calibrate the handpiece and drill.
5. Attach tracking marker to patient or dentition.
6. Register patient anatomy with virtual data.
7. Perform drill preparation while monitoring real-time position, angulation, and depth.
8. Confirm canal location and complete conventional endodontic treatment.

Features

• No printed guide is required.
• Path can be modified during the procedure.
• Particularly useful for posterior teeth and limited mouth opening.
• Allows visual control of drill angulation and depth in real time.

7. Clinical Applications

7.1 Calcified and Obliterated Canals

• Trauma
• Age-related dentine deposition
• Caries
• Long-standing irritation
• Restorative procedures
• Orthodontic treatment
• Pulpal inflammation

7.2 Fibre Post Removal

• Root perforation
• Excessive dentine removal
• Loss of remaining coronal structure

7.3 Endodontic Retreatment

• Access obstructed canals.
• Remove restorative materials.
• Bypass difficult coronal obstructions.
• Locate missed canals in selected cases.

7.4 Teeth with Developmental Anomalies

• Dens invaginatus
• Dens evaginatus
• Taurodontism
• Teeth with unusual root morphology
• Malformed teeth
• Rotated or tipped teeth

7.5 Access Through Restorations

• Ceramic crowns
• Full-coverage restorations
• Complex prosthetic restorations
• Calcium silicate materials such as MTA in selected retreatment cases

7.6 Endodontic Microsurgery

• Precise osteotomy
• Root-end localization
• Apicoectomy
• Root-end cavity preparation
• Avoidance of critical structures such as the maxillary sinus, mental foramen, and adjacent roots

8. Indications

9. Contraindications and Limitations

Contraindications

• Tooth with hopeless periodontal or restorative prognosis.
• Vertical root fracture.
• Root with insufficient thickness along planned drill path.
• Severe root curvature when a straight guided path is not possible.
• Inability to obtain stable guide seating.
• Patient unable to open mouth sufficiently for guide and drill placement.
• Inadequate CBCT quality or major artefacts that prevent reliable planning.
• Inability to isolate tooth appropriately.
• Lack of access to suitable digital planning, printing, or navigation system.

Limitations of Static Guidance

• Requires a relatively straight path to target.
• Difficult in severely curved roots.
• Limited usefulness in posterior regions with restricted interocclusal space.
• Requires planning, guide fabrication, and an additional appointment in many situations.
• Cannot be altered once guide is fabricated.
• Accuracy depends on scan quality, image merging, template fit, sleeve tolerance, and correct seating.
• May be difficult in emergency treatment.
• Requires CBCT exposure and increases cost.

Limitations of Dynamic Navigation

• High acquisition and maintenance cost.
• Requires training, hand-eye coordination, and familiarity with monitor-guided work.
• Calibration and registration errors can affect accuracy.
• Operator must look at the screen rather than continuously at the tooth.
• System hardware can be bulky.
• The technique remains operator-dependent.

10. Advantages

General Advantages

• Precise and predictable canal location.
• Conservative removal of tooth structure.
• Lower risk of iatrogenic perforation.
• Greater safety in calcified canal cases.
• Improved treatment confidence in complex anatomy.
• Potential reduction in procedural errors.
• Better preoperative visualization and communication.
• Useful educational tool for postgraduate training.

Advantages of Static Guidance

• Reproducible and relatively easy to follow.
• Less demanding intraoperative hand-eye coordination.
• Can be used effectively by operators with limited experience after appropriate planning.
• Does not require real-time navigation equipment.
• Good stability when template is accurately fabricated and well seated.

Advantages of Dynamic Navigation

• Real-time adjustment of bur direction and depth.
• No need for a printed guide.
• Useful in posterior teeth and limited mouth opening.
• May be used in urgent cases without waiting for guide fabrication.
• Direct visualization of field is retained.
• Can accommodate changes made during treatment.

11. Disadvantages

12. Static versus Dynamic Guided Endodontics

13. Guided Endodontic Microsurgery

Uses

• Localization of root apex.
• Accurate osteotomy.
• Root-end resection.
• Root-end cavity preparation.
• Avoidance of vital anatomical structures.
• Reduced size of osteotomy.
• Management of difficult surgical access.

Basic Workflow

1. CBCT assessment of lesion and root apex.
2. Surface scan and virtual planning.
3. Determination of osteotomy site, depth, and angle.
4. Fabrication of static surgical guide or use of dynamic navigation.
5. Guided osteotomy and root-end resection.
6. Root-end preparation and retrograde filling.
7. Flap repositioning and suturing.

14. Errors and Complications

Possible Errors

• Incorrect CBCT interpretation.
• Poor scan superimposition.
• Inaccurate virtual planning.
• Inadequate guide seating.
• Distortion during guide fabrication.
• Sleeve-bur mismatch.
• Drill deflection.
• Excessive drill length or depth.
• Overheating due to inadequate irrigation.
• Inaccurate dynamic navigation registration.
• Patient movement during dynamic navigation.

Complications

• Root perforation.
• Excessive dentine removal.
• Canal deviation.
• Thermal damage to dentine or periodontal tissues.
• Inability to negotiate the canal even after guided access.
• Crack initiation from large-diameter drills.
• Damage to adjacent tooth structure.
• Failure to locate canal due to complete obliteration.

Prevention

• Use a small field-of-view CBCT of adequate resolution.
• Verify guide fit before drilling.
• Use rubber dam isolation.
• Confirm drill length with a stopper.
• Plan adequate safety margins from root surface.
• Use adequate irrigation and intermittent drilling.
• Use suitable small-diameter drills where possible.
• Confirm canal path with small hand files after guided access.
• Avoid relying on guidance when root anatomy or canal visibility is uncertain.
• Maintain conventional endodontic principles after access preparation.

15. Evidence and Future Directions

• [Systematic Review . Tier 1 . 2025] Kapoor et al. Dynamic Navigation in Endodontics: Scope, Benefits, and Challenges - A Systematic Review. PMID: 40287086.
• [Systematic Review . Tier 1 . 2022] Vasudevan et al. Dynamic Navigation in Guided Endodontics - A Systematic Review. PMID: 35786584.

• Improved CBCT resolution with lower radiation dose.
• Faster and more accurate scan registration.
• Artificial intelligence-assisted canal detection.
• Smaller and more ergonomic navigation systems.
• Better low-cost chairside 3D printing.
• Augmented reality-assisted endodontics.
• More clinical trials comparing guided and conventional treatment.

16. Conclusion

Endodontics Versus Dental Implants: A Comparative Review

Table of Contents

1. Introduction
2. Definitions
3. Therapeutic objectives
4. Fundamental principle: preserve or replace?
5. Factors determining treatment choice
6. Endodontic treatment
7. Dental implant treatment
8. Comparison between endodontics and implants
9. Success, survival, and failure
10. Complications
11. Patient-related factors
12. Tooth-related factors
13. Periodontal and restorative factors
14. Aesthetic considerations
15. Cost and time considerations
16. Clinical decision-making algorithm
17. Situations favouring endodontic treatment
18. Situations favouring extraction and implant placement
19. Role of retreatment and endodontic microsurgery
20. Conclusion

1. Introduction

Preserve a natural tooth whenever it has a predictable restorative, periodontal, and endodontic prognosis. Extract and replace it only when retention is impractical, unpredictable, or harmful.

2. Definitions

Endodontic Treatment

Aim

• Eliminate infection from the root canal system.
• Prevent reinfection.
• Promote healing of periapical tissues.
• Retain the natural tooth in function.

Dental Implant

Aim

• Replace a missing or non-restorable tooth.
• Restore mastication, phonetics, aesthetics, and occlusal stability.
• Preserve function without preparation of adjacent teeth.

3. Therapeutic Objectives

4. Fundamental Principle: Preserve or Replace?

Can the tooth be predictably restored and maintained in health and function over time?

• Adequate periodontal support.
• Sufficient remaining sound tooth structure.
• A favourable crown-root ratio.
• No vertical root fracture.
• A treatable root canal system.
• A restoratively achievable ferrule.
• Adequate biological width or supracrestal tissue attachment after restoration.
• An acceptable long-term prognosis.

5. Factors Determining Treatment Choice

A. Tooth-related factors

• Amount of remaining coronal tooth structure.
• Root length and root morphology.
• Root canal anatomy.
• Presence of canal calcification.
• Root perforation.
• Internal or external resorption.
• Root fracture.
• Furcation involvement.
• Crown-root ratio.
• Possibility of obtaining an adequate ferrule.
• Restorability after caries removal.

B. Periodontal factors

• Attachment level and bone support.
• Mobility.
• Furcation involvement.
• Plaque control.
• Periodontal disease activity.
• Width of keratinized tissue.
• Crown lengthening requirement.
• Prognosis of adjacent teeth.

C. Patient-related factors

• General health and medical history.
• Smoking.
• Diabetes control.
• Oral hygiene and compliance.
• History of periodontitis.
• Parafunction, especially bruxism.
• Aesthetic expectations.
• Time, cost, and ability to attend maintenance visits.

D. Implant-site factors

• Adequate bone volume and quality.
• Need for grafting.
• Relationship to maxillary sinus, inferior alveolar nerve, and adjacent roots.
• Soft-tissue thickness and smile line.
• Interocclusal space.
• Position and condition of adjacent teeth.
• Presence of active periodontal disease.

6. Endodontic Treatment

Indications

• Irreversible pulpitis.
• Pulp necrosis.
• Acute or chronic apical periodontitis.
• Periapical abscess after emergency management.
• Traumatic pulp exposure.
• Tooth requiring post and core with an otherwise favourable prognosis.
• Previously treated tooth requiring nonsurgical retreatment.
• Tooth with a periapical lesion amenable to conventional treatment or apical surgery.

Advantages of Endodontic Treatment

• Retains the natural tooth.
• Preserves periodontal ligament and proprioception.
• Avoids extraction and implant surgery.
• Usually completed in less overall treatment time.
• Often less expensive than extraction, grafting, implant placement, and crown restoration.
• Maintains alveolar bone contours around the existing tooth.
• Avoids surgical risks of implant placement.
• May improve oral-health-related quality of life.

Limitations

• Success depends on adequate disinfection, obturation, and coronal seal.
• Treatment may fail because of missed anatomy, persistent infection, coronal leakage, root fracture, or poor restoration.
• A heavily destroyed tooth may need post, core, crown lengthening, orthodontic extrusion, or crown.
• Retreatment may be complex and costly.
• The tooth may ultimately require extraction if it fractures or remains infected.

7. Dental Implant Treatment

Indications

• Non-restorable caries.
• Vertical root fracture.
• Severe root resorption.
• Inadequate remaining root length.
• Hopeless periodontal prognosis.
• Extensive furcation involvement with poor prognosis.
• Repeated endodontic failure where retreatment or apical surgery is unlikely to succeed.
• Root perforation or fracture that cannot be repaired.
• Unfavourable crown-root ratio after crown lengthening.
• Patient preference after adequate informed discussion.

Advantages of Implants

• Replace a missing tooth without preparing adjacent teeth.
• High long-term survival in properly selected and maintained patients.
• Restore masticatory function and aesthetics.
• Useful where no tooth structure remains to retain.
• Can support crowns, bridges, and overdentures.
• Avoids retaining a tooth with poor long-term prognosis.

Limitations

• Requires extraction and surgical intervention.
• May require bone grafting, sinus lift, or soft-tissue augmentation.
• Osseointegration is not guaranteed.
• Susceptible to peri-implant mucositis and peri-implantitis.
• Usually more costly.
• Often requires a longer treatment course.
• Needs lifelong plaque control and professional maintenance.
• Implant failure can lead to loss of bone and make future replacement difficult.

8. Comparison Between Endodontics and Implants

9. Success, Survival, and Failure

Success versus Survival

Endodontic Success

• No pain or swelling.
• No sinus tract.
• Normal function.
• No progressive periapical radiolucency.
• Evidence of complete or acceptable periapical healing.
• No need for further treatment.

Endodontic Survival

Implant Success

• Osseointegration.
• No mobility.
• Absence of persistent pain or infection.
• Stable peri-implant tissues.
• Acceptable bone levels.
• Functional and aesthetic restoration without major complication.

Implant Survival

10. Complications

Complications of Endodontically Treated Teeth

Biological complications

• Persistent intraradicular infection.
• Missed canal.
• Inadequate cleaning and shaping.
• Inadequate obturation.
• Coronal leakage.
• Persistent apical periodontitis.
• Endodontic-periodontal lesion.
• External inflammatory root resorption.

Structural complications

• Crown fracture.
• Cusp fracture.
• Post dislodgement.
• Core fracture.
• Restoration failure.
• Vertical root fracture.
• Root perforation.
• Loss of ferrule.

Management

• Nonsurgical retreatment.
• Endodontic microsurgery.
• Repair of perforation.
• New coronal restoration.
• Crown lengthening or orthodontic extrusion in selected cases.
• Extraction only when tooth becomes non-restorable or prognosis is hopeless.

Complications of Implants

Biological complications

• Failure of osseointegration.
• Peri-implant mucositis.
• Peri-implantitis.
• Marginal bone loss.
• Soft-tissue recession.
• Implant exposure.
• Infection.

Mechanical complications

• Screw loosening.
• Screw fracture.
• Abutment fracture.
• Crown loosening.
• Ceramic chipping or fracture.
• Implant fracture.
• Occlusal overload.

Surgical complications

• Damage to adjacent teeth.
• Sinus perforation.
• Inferior alveolar nerve injury.
• Haemorrhage.
• Inadequate implant position.
• Graft failure.

11. Patient-Related Factors

Smoking

• Periodontal healing.
• Osseointegration.
• Implant survival.
• Risk of peri-implantitis.
• Endodontic and restorative prognosis indirectly through periodontal effects.

Diabetes

• Wound healing.
• Infection control.
• Osseointegration.
• Periodontal health.

History of Periodontitis

Bisphosphonates and Antiresorptive Drugs

Parafunction

• Fracture of endodontically treated teeth and restorations.
• Implant crown fracture.
• Screw loosening.
• Implant overload and marginal bone loss.

12. Tooth-Related Factors

Remaining Tooth Structure

Ferrule Effect

Root Fracture

Root Length and Crown-Root Ratio

13. Periodontal and Restorative Factors

Factors Supporting Tooth Retention

• Healthy or treatable periodontium.
• Adequate bone support.
• Mild or absent mobility.
• No advanced furcation involvement.
• Adequate attached gingiva.
• Ability to maintain plaque control.
• Ability to restore without violating supracrestal tissue attachment.

Factors Favouring Extraction

• Advanced attachment loss.
• Severe mobility.
• Untreatable furcation involvement.
• Generalized uncontrolled periodontitis.
• Inability to achieve a maintainable restoration.
• Severe root proximity or poor access for hygiene.
• Vertical root fracture.

14. Aesthetic Considerations

• Smile line.
• Gingival biotype.
• Papilla height.
• Tooth position.
• Bone thickness.
• Soft-tissue contour.
• Presence of adjacent teeth.
• Site of tooth loss.

Endodontic Treatment

Implant

• Midfacial recession.
• Loss of papilla.
• Grey shine-through in thin gingiva.
• Asymmetrical gingival margins.
• Difficulty matching the contralateral tooth.
• Soft-tissue and bone deficiency after extraction.

15. Cost and Time Considerations

16. Clinical Decision-Making Algorithm

Step 1: Is the tooth restorable?

• If yes, proceed to periodontal and endodontic assessment.
• If no, extraction and replacement planning are indicated.

Step 2: Is there a vertical root fracture?

• If yes, extraction is usually indicated.
• If no, continue assessment.

Step 3: Is periodontal support adequate?

• If periodontal disease is treatable and tooth support is adequate, retain the tooth where possible.
• If periodontal prognosis is hopeless, extraction may be indicated.

Step 4: Can a durable restoration be achieved?

• Ferrule.
• Crown-root ratio.
• Need for crown lengthening.
• Need for orthodontic extrusion.
• Ability to isolate and restore.
• Functional loading.

Step 5: Is the root canal system treatable?

• Primary endodontic treatment.
• Nonsurgical retreatment.
• Endodontic microsurgery.
• Guided endodontics for calcified canals, where appropriate.

Step 6: If extraction is necessary, is implant placement suitable?

• Bone volume.
• Need for grafting.
• Medical status.
• Smoking.
• Periodontal status.
• Aesthetic demands.
• Oral hygiene.
• Patient preference.

Step 7: Discuss alternatives and obtain informed consent

• Root canal treatment and crown.
• Retreatment.
• Endodontic microsurgery.
• Extraction and implant-supported crown.
• Fixed partial denture.
• Resin-bonded bridge.
• Removable partial denture.
• Extraction without replacement in selected non-strategic teeth.

17. Situations Favouring Endodontic Treatment

1. The tooth is restorable.
2. There is adequate periodontal support.
3. No vertical root fracture is present.
4. An adequate ferrule can be obtained.
5. Root canal anatomy is treatable.
6. Periapical pathology has a good healing prognosis.
7. The patient has high aesthetic risk for implant treatment.
8. The patient is young and skeletal growth is incomplete.
9. There is inadequate implant-site bone without extensive grafting.
10. The patient has uncontrolled systemic disease or high surgical risk.
11. The patient is a heavy smoker or has active periodontal disease.
12. Cost or treatment time makes implants impractical.
13. The tooth is strategically important for maintaining alveolar bone and occlusion.

18. Situations Favouring Extraction and Implant Placement

1. The tooth is non-restorable.
2. There is a confirmed vertical root fracture.
3. Extensive caries extends too far subgingivally for predictable restoration.
4. The root is severely resorbed or perforated beyond repair.
5. Advanced periodontal disease produces a hopeless prognosis.
6. Crown lengthening would result in an unacceptable crown-root ratio or furcation exposure.
7. Repeated endodontic treatment has failed and retreatment or surgery has poor prognosis.
8. Adequate ferrule cannot be achieved.
9. The tooth has severe structural destruction with inadequate remaining root.
10. Implant site anatomy, systemic health, oral hygiene, and patient expectations are favourable.

19. Role of Retreatment and Endodontic Microsurgery

Nonsurgical Retreatment

• Inadequate obturation.
• Missed canal.
• Coronal leakage.
• Persistent intraradicular infection.
• Defective restoration.
• Incomplete previous treatment.

Endodontic Microsurgery

• Orthograde retreatment is impractical.
• A post or crown cannot be removed safely.
• There is persistent apical disease after adequate conventional treatment.
• There is apical obstruction, separated instrument, or inaccessible anatomy.

20. Conclusion

• Restorability.
• Periodontal prognosis.
• Endodontic prognosis.
• Presence or absence of root fracture.
• Ferrule and crown-root ratio.
• Implant-site anatomy.
• Medical and periodontal risk factors.
• Aesthetic demands.
• Cost, time, and patient preferences.

Asepsis in Endodontics and Conservative Dentistry

Table of Contents

1. Definition
2. Objectives
3. Sources of contamination
4. Universal infection-control measures
5. Asepsis in conservative dentistry
6. Asepsis in endodontics
7. Role of rubber dam
8. Sterilization of instruments
9. Conclusion

1. Definition

2. Objectives of Asepsis

• Prevent cross-infection between patients and dental personnel.
• Prevent contamination of the operative field by saliva, blood, aerosol, and dental plaque.
• Prevent entry of microorganisms into cavity preparations and root canals.
• Protect the patient from accidental swallowing or aspiration of instruments.
• Improve the prognosis of restorations and root canal treatment.

3. Sources of Contamination

• Saliva and blood.
• Dental plaque and caries.
• Aerosols generated by handpieces and ultrasonic devices.
• Contaminated instruments, burs, files, and handpieces.
• Dental unit waterlines and suction tubing.
• Unwashed hands, gloves, masks, and contaminated surfaces.
• Leakage around poorly placed rubber dam.
• Contaminated restorative materials or medicaments.

4. Universal Infection-Control Measures

A. Hand hygiene

• Wash hands before and after treatment.
• Use alcohol-based hand rub when hands are not visibly soiled.
• Keep fingernails short and clean.
• Avoid rings, watches, and jewellery during clinical work.

B. Personal protective equipment

• Gloves.
• Surgical mask.
• Protective eyewear or face shield.
• Clinical gown or apron.

C. Instrument processing

• Clean instruments to remove debris.
• Package instruments.
• Sterilize by steam autoclaving.
• Store sterilized packs in a clean, dry area.
• Use sterile instruments for every patient.

D. Surface disinfection

E. Biomedical waste disposal

• Dispose of sharps in puncture-resistant sharps containers.
• Segregate contaminated waste according to local biomedical-waste regulations.
• Never recap needles using two hands.

5. Asepsis in Conservative Dentistry

Measures

1. Preprocedural mouth rinse
   A suitable antimicrobial mouth rinse may reduce oral microbial load and aerosols.
2. Isolation of the operative field
   • Rubber dam is ideal where feasible.
   • Cotton rolls, saliva ejector, retractors, and high-volume suction may be used for simpler procedures.
3. Cleaning of tooth surface
   Remove plaque, calculus, and debris before cavity preparation.
4. Use of sterile or disinfected burs
   Burs must be properly cleaned and sterilized or disposed of if single use.
5. High-volume evacuation
   Reduces aerosol and splatter during cavity preparation.
6. Avoiding contamination during restoration
   Prevent saliva, blood, and gingival crevicular fluid contamination, particularly during adhesive procedures and placement of composite resin, glass ionomer, or sealants.
7. Proper matrix and wedge placement
   A clean, dry field prevents contamination and promotes proper adaptation of restorative material.

6. Asepsis in Endodontics

Steps of Endodontic Asepsis

1. Preoperative measures

• Review medical history.
• Use PPE and standard precautions.
• Perform preprocedural mouth rinse where appropriate.
• Clean the tooth and surrounding area.
• Remove gross caries and defective restorations before entering the pulp chamber whenever possible.

2. Rubber dam isolation

3. Disinfection of operative field

• Disinfect the exposed tooth, clamp, surrounding dam, and operative field with an appropriate disinfectant.
• Sodium hypochlorite is commonly used for this purpose in endodontic practice.
• Prevent contamination from saliva around the clamp or dam.

4. Sterile instruments

• Use sterilized endodontic explorers, excavators, burs, files, reamers, spreaders, pluggers, and clamps.
• Use sterile paper points and absorbent points.
• Use sterile irrigating needles and syringes.
• Avoid touching sterile instruments with contaminated gloves or surfaces.

5. Aseptic root canal preparation

• Establish access without saliva contamination.
• Use irrigants properly and safely.
• Maintain patency and canal cleanliness using sterile instruments.
• Use fresh sterile files as per protocol.
• Avoid placing contaminated instruments back into prepared canals.

6. Intracanal medicaments and temporary restoration

• Place medicaments with sterile instruments.
• Seal the access cavity with a well-adapted temporary restoration.
• A defective temporary seal allows coronal leakage and reinfection.

7. Obturation

• Ensure the canal is dry using sterile paper points.
• Use aseptic obturation materials and instruments.
• Obtain an immediate and adequate coronal seal after obturation.

7. Role of Rubber Dam

Functions

• Isolates the tooth from saliva and oral microorganisms.
• Prevents contamination of root canals during treatment.
• Retracts cheeks, lips, tongue, and gingiva.
• Improves visibility and access.
• Provides a dry field for adhesive restorative procedures.
• Prevents swallowing or aspiration of endodontic files, burs, clamps, and irrigants.
• Protects soft tissues from irrigants such as sodium hypochlorite.
• Reduces aerosol contamination.

8. Sterilization of Endodontic Instruments

9. Conclusion