A lower molar presented with extensive caries extending subcrestally, structural compromise, and undermined cusps. The tooth required microscope-guided caries removal, endodontic therapy, deep margin elevation (DME), and cuspal coverage to restore structural biomechanics and long-term function.

Retention was achieved through adhesive dentistry, avoiding unnecessary crown preparations and preserving sound tooth structure.

2. Pre-Operative Analysis

Key findings

Gross caries undermining both proximal and occlusal surfaces
Subcrestal deep margin with loss of supragingival enamel
Inflamed pulp → symptomatic irreversible pulpitis / necrosis
Existing restoration failure
Healthy adjacent periodontal support

Goal:

Restore the tooth with a biomimetic approach, rebuilding each structural layer while ensuring long-term load resistance and predictable adhesion.

3. Clinical Workflow

A. Isolation & Caries Removal

Absolute isolation using a rubber dam and clamps
Removal of infected dentin under microscope magnification
Peripheral seal created by preserving sound enamel at the cavosurface
Structural assessment confirmed the need for cuspal reinforcement

Clinical importance:

Isolation ensures predictable hybrid layer formation and prevents contamination—critical for adhesive success.

B. Endodontic Therapy

Performed under high magnification for accuracy:

Protocol

Glide path established
Canals shaped with NiTi rotary instrumentation
Irrigation: NaOCl + EDTA protocol
Canals dried and obturated with bioceramic sealer + GP single cone
(chosen for its bioactivity, dimensional stability, and superior sealing)

Why bioactive sealer?

Stimulates hydroxyapatite formation
Produces chemical bonding to dentin
Reduces microleakage at the sealer–dentin interface

Coronal Seal

Immediate bulk-fill flowable dentin replacement to block microleakage
This step is strongly supported in the literature for long-term success

C. Deep Margin Elevation (Two-Step DME)

The cervical margin was subcrestal, making isolation and adhesive bonding impossible without DME.

Step 1 – Cervical Sealing

Flowable resin composite placed as gingival seat
Adapted with transparent matrices for tight cervical adaptation
Objective: seal the dentin and block fluids from the sulcus

Step 2 – Final Elevation

Layer of packable composite built to bring the margin supra-gingival
Margin finished to crisp enamel to enable predictable bonding for final restoration

Why DME?

Preserves the tooth
Avoids crown lengthening surgery
Maintains periodontal biology
Creates a clean, accessible, bondable margin

This technique is well validated for MOD, deep proximal, and subgingival lesions.

D. Cuspal Coverage Restoration

Given the structural loss, cuspal reinforcement was mandatory.

Composite Onlay-Style Build-Up

Adhesive: Universal adhesive with selective enamel etching
Dentin replacement: High-strength composite
Enamel layer: Esthetic nano-hybrid composite with anatomical layering
Functional morphology sculpted under microscope

Why composite cuspal coverage?

Superior stress distribution
Biomimetic modulus of elasticity close to dentin
Tooth preservation vs. full crown prep
Less chair time and lower biological cost

E. Post-Operative Evaluation

Clinical outcomes

✔ Excellent marginal integrity

✔ Healthy gingival response

✔ Proper occlusal contacts and harmony

✔ Smooth transition from tooth to composite

✔ Anatomical fissures and functional cusps maintained

✔ Radiographs confirm complete obturation and dense coronal seal

Patient feedback

Comfortable
Excellent function
Natural appearance

4. Final Summary for Zerodont

Extreme caries + subcrestal margin + endodontic therapy = predictable long-term success through biomimetic adhesive dentistry.

Two-step DME converted an impossible margin into a perfect bonding field.

Cuspal coverage restored biomechanics and load-bearing function.

A tooth that was otherwise headed for extraction was saved conservatively.

5. References (Peer-Reviewed)

These support DME, bioceramic sealers, composite cuspal coverage, and adhesive dentistry.

Deep Margin Elevation & Adhesive Protocols

Dietschi D, Spreafico R. Deep margin elevation: principles and clinical guidelines. International Journal of Esthetic Dentistry. 2015;10(3):334–357.
Schlichting LH et al. Marginal integrity of deep margin elevation vs crown lengthening. J Esthet Restor Dent. 2019;31(4):366–373.

Cuspal Coverage & Biomimetic Restorations

Rocca GT, Krejci I. Bonded indirect restorations for severely compromised posterior teeth. Journal of Adhesive Dentistry. 2015;17:146–154.
França FMG et al. Impact of cuspal coverage on endodontically treated teeth restored with composite. Operative Dentistry. 2018;43(3):219–228.

Endodontics & Bioceramic Sealers

Zhang W, Li Z, Peng B. Assessment of bioceramic sealer sealing ability. Journal of Endodontics. 2009;35(5): 620–623.
Torabinejad M, Parirokh M. Mineral trioxide aggregate and bioactive sealers in endodontics. Journal of Endodontics. 2010;36(1):16–27.

Coronal Seal Importance

Ray HA, Trope M. Periapical status related to quality of coronal restoration and RCT. Endodontic Journal. 1995;21(7): 26–30.
Saunders WP, Saunders EM. Key role of coronal seal in preventing reinfection. Journal of Endodontics. 1990;16(9): 445–449.

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Hamza dental center

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