RPD Solutions For Lingually Inclined Lower Teeth

Jonathan Hughes, our CDT, recently completed a challenging case for a patient he treated at Clover House Dental Practice.

The patient presented with lingually inclined lower four, five and six on the right-hand side of the arch and a lingually inclined lower left four on the opposite side. This tooth inclination created a challenging insertion path. A gap between the soft tissue and the denture in the area of the inclined teeth would be impossible to avoid with a chrome sublingual/lingual bar or conventional acrylic denture.

Jonathan discussed two options with the patient.

Option one: The provision of a DuraCetal framework—a pure, highly crystalline acetal copolymer resin and a lightweight alternative to metal frameworks. DuraCetal frameworks are digitally designed on 3 Shape and milled in-house from Myerson Milling Discs. They are available in various Vita shades: A1, A2, A3, A3.5, B1, C1 and, G2—allowing for naturally aesthetic clasps. The advantage of DuraCetal frames over Ultaire AKP, our other metal-free option, is that they possess a high tensile strength, allowing them to flex over undercuts and spring back into position without breaking or losing shape—perfect for a case like this.

Option two: A cobalt chrome dental bar—a chrome without a lingual or sublingual bar; the major connector is effectively one continuous clasp on the lingual aspect of the remaining natural teeth. The design also keeps the gingival margins uncovered, encouraging good oral health, but only possible if there are no gaps between the anterior natural teeth as aesthetically metal showing between teeth wouldn’t be accepted by the patient.

Ultimately, the patient opted for a dental bar Chrome RPD.

A cad image of the chrome designed, ready to be laser sintered.

A dental bar must be robust enough without being too bulky to help patient tolerance—this can be challenging! Luckily the patients remaining lower canines and lower right two were long enough to allow for a broad connector, meaning we could keep the metal thin and flat to the clinical crowns. We added rest seats to the lower left four and the lower right four and six to provide additional tooth support. For retention, we added a ring clasp to the lower right six, with the final third of the clasp arm engaging the mesial lingual undercut of the tooth. We also added gingivally-approaching clasps to each of the first premolars for extra stability.

The patient was satisfied with the try-in, and we proceeded to fit.

The finished denture needed minimal adjustments at the fit appointment, and the patient was pleased with the result.