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Major Connector (major + connector)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamics

JOURNAL OF ORAL REHABILITATION, Issue 11 2008
H. ITOH
Summary, Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought-wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co-Cr major connector and heat-cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three-dimensional displacements of the RPDs were measured under a simulated 30-N loading with a displacement transducer type M-3. Significant effects of "direct retainer design" on bucco-palatal displacements and "major connector" on mesio-distal displacements were revealed by 2 × 3 two-way analysis of variance of abutment teeth movements (P < 0·001 and P = 0·002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of "direct retainer design" on corono-apical displacements and "major connector" on mesio-distal displacements (P = 0·001 and P = 0·028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD. [source]

Load transfer characteristics of unilateral distal extension removable partial dentures with polyacetal resin supporting components

AUSTRALIAN DENTAL JOURNAL, Issue 1 2009
T Jiao
Abstract Background:, To photoelastically examine load transfer by unilateral distal extension removable partial dentures with supporting and retentive components made of the lower stiffness polyacetal resins. Methods:, A mandibular photoelastic model, with edentulous space distal to the right second premolar and missing the left first molar, was constructed to determine the load transmission characteristics of a unilateral distal extension base removable partial denture. Individual simulants were used for tooth structure, periodontal ligament, and alveolar bone. Three designs were fabricated: a major connector and clasps made from polyacetal resin, a metal framework as the major connector with polyacetal resin clasp and denture base, and a traditional metal framework I-bar removable partial denture. Simulated posterior bilateral and unilateral occlusal loads were applied to the removable partial dentures. Results:, Under bilateral and left side unilateral loading, the highest stress was observed adjacent to the left side posterior teeth with the polyacetal removable partial denture. The lowest stress was seen with the traditional metal framework. Unilateral loads on the right edentulous region produced similar distributed stress under the denture base with all three designs but a somewhat higher intensity with the polyacetal framework. Conclusions:, The polyacetal resin removable partial denture concentrated the highest stresses to the abutment and the bone. The traditional metal framework I-bar removable partial denture most equitably distributed force. The hybrid design that combined a metal framework and polyacetal clasp and denture base may be a viable alternative when aesthetics are of primary concern. [source]

Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamics

JOURNAL OF ORAL REHABILITATION, Issue 11 2008
H. ITOH
Summary, Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought-wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co-Cr major connector and heat-cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three-dimensional displacements of the RPDs were measured under a simulated 30-N loading with a displacement transducer type M-3. Significant effects of "direct retainer design" on bucco-palatal displacements and "major connector" on mesio-distal displacements were revealed by 2 × 3 two-way analysis of variance of abutment teeth movements (P < 0·001 and P = 0·002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of "direct retainer design" on corono-apical displacements and "major connector" on mesio-distal displacements (P = 0·001 and P = 0·028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD. [source]