- Main complexity is to achieve natural occlusion
- One arch is natural = some wear and tear, crowns and fillings will be present.
- Sometimes, Natural teeth = maloppsed, tipped
- Probility = not good smooth or uneven occlusion plane seen in fabricated denture
- This will destablize the denture and ride resorption is faster
- Acyrlic teeth = FAST wear and tear
- Porcelain teeth results in the wear of the natural teeth.
- Most preffered teeth = teeth with metal occlusion
- Types
- SCD opposing natural teeth.
- SCD opposinga(pre-existing)complete denture
- SCD opposing a removable partial denture.
- SCD opposing an overdenture.
- PROBLEMS
- A mandibular SCD opposing upper natural teeth is extremely complicated.
- The reduced surface area of the lower ridge results in excessive forces on the ridge resulting in rapid bone resorption.
- The lower SCD is therefore rarely indicated.
- The upper SCD opposing lower natural anterior teeth often results in the combination syndrome sequence 1
- Excessive load on the anterior region of the complete denture
- Ridge resorption in the maxillary anterior region.
- Epulis fissuratum is formed at the maxillary labial sulcus
- Downward movement of posterior plane of occlusion producing excessive resorption of the mandibular posterior region
- Downward tilting of the occlusal plane in the posterior region produces an anterior openbite which leads to supraeruption of the lower anteriors.
- This increases the load on the anterior region of the upper denture producing a vicious cycle
- Combination syndrome type 2
- Ridge resorption in the mandibular edentulous area
- Downward movement of the posterior part of maxillary denture and the formation of flabby tissue
- Supra-eruption of lower anteriors
- Increased load in the anterior maxillary region of the complete denture
- Resorption in the anterior portion of maxillary ridge and the formation of flabby tissue
- The fixed position of lower anterior natural teeth gives us less flexibility for aesthetic placement of upper natural teeth.
- Fracture of the SCD is a common problem, especially if opposed by natural teeth, because of the forces generated by the natural teeth.
- A mandibular SCD opposing upper natural teeth is extremely complicated.
