Great option for replacing lateral incisors with cantilever resin-bonded fixed dental prostheses (Maryland bridge)

Introduction:

• Congenitally missing teeth most common malformation in humans
  
• Maxillary lateral incisors most commonly missing in anterior region, also the most commonly missing bilaterally
  
• Maxillary central incisors most commonly affected by trauma
  
• Main treatment options = autotransplantation, orthodontic space closure, resin-bonded fixed dental prostheses (RBFDP), implants, and conventional fixed dental prostheses
  
• Cantilever resin-bonded fixed dental prostheses (RBFDPs)
  
  • Minimally invasive
    
  • Low in cost
    
  • Reversible
    
  • No risk for pulpal irritation
    
  • No need for anesthesia
    
  • Minimal risk for caries development
    
  • Valid option for younger patients
    

Purpose:

• Determine the long-term success and survival rates of cantilever zirconia ceramic RBFDP replacing incisor (Cantilever “Maryland” bridge)
  

Material & Methods:

• Retrospective clinical evaluations
  
• Inclusion
  
  • 1 or 2 missing incisors
    
  • Abutment teeth were caries-free or minor defects, sound enamel
    
  • Abutment teeth free of periodontitis
    
  • Edentulous space is size of missing tooth
    
  • Appropriate occlusion with at least 0.7mm thickness of retainer wing
    
  • Retention phase of at least 3 months after active orthodontic therapy
    
  • COmmitment to attend annual recalls
    
• Impressions + die stone
  
• CAD/CAM milled pre-sintered zirconia ceramic blocks and manually veneered
  
• Minimal thickness of zirconia wing is 0.7mm, connector 2mm horizontally x 3mm vertically
  
• Protocol of insertion
  
  • Alumina particles abraded
    
  • Ultrasonic cleanse in 99% isopropanol
    
  • Rubber dam isolation
    
  • 37% phosphoric acid etch 30 secs
    
  • Adhesive system (Panavia 21TC or Multilink automix)
    
• 59 patients = 1 cantilever RBFDP
  
• 21 patients = 2 cantilever RBFDP
  
• 7 patients = bilateral cantilever RBFDP splinted at midline for maintain orthodontic diastema closure
  
• 3 Groups
  
  • G1 = Congenitally missing 59.6%
    
  • G2 = Traumatic 13.2%
    
  • G3 = Other reasons (Periodontitis, caries, orthodontic treatments) 27.2%
    

Results:

• Mean observations 92.2 months
  
• 6 restorations rebonded, no further complications
  
• With complications, success rate 92.0% after 10yrs
  
  • Despite debonding, no statistically significant difference among all 3 groups
    
• Loss of restoration as failure, survival rate 98.2% after 10 years
  

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