Mandibular Free End Saddle Research Articles

Denture Clasp Injury of the Oral Mucosa.

Purpose: Clasp-penetrating oral injury caused by removable partial dentures is basically a minor injury but can also cause complications such as continuous bleeding. No systematic investigations of clasp injury have been undertaken. The aims of this study were to reveal the characteristics of clasp injury and estimate variables associated with clasp injury of the oral mucosa. Methods: This retrospective study used clasp injury as the outcome variable, with primary predictor variables of demographic characteristics, medical history, local characteristics, and denture design, including the site of the affected clasp. Denture type was examined according to the classification of Kennedy. Collected data were statistically analyzed using the χ2 test or Fisher's exact test and the level of significance adopted was 5%. Results: This report consists of 73 cases (36 men and 37 women), of which 31 cases had precise denture information. Among them, clasp injuries were more common with Class I (51.6%) and Class II (32.3%) dentures (p < .001). Premolar (64.5%) and canine clasps (32.3%) were significantly more frequently involved (p < .001). Conclusion: Clasp injury of the oral mucosa was significantly more common on the tongue, and mandibular free-end saddle dentures with premolar or canine clasps were the most notable risk factor for clasp-penetrating injury of the oral mucosa.

ACCURACY OF GUIDED IMPLANT INSERTION IN MANDIBULAR FREE-END SADDLE AREAS USING STEREOLITHOGRAPHIC SURGICAL STENT

Introduction: The success of implant therapy depends primarily on appropriate treatment planning and properly performed implant placement surgery.Guided implant surgery (template based guided cavity preparation and guided implant insertion) is effective to guide the implant placement.This can be achieved by means of a surgical guide Stent.Stents are designed in conventional methods or stereolithography which allows the fabrication of surgical guides from 3D computer generated models for precise placement of the implants. Objectives: Assess the accuracy of stereolithographic surgical stent to orientate implant insertion in mandibular free-end saddle areas. Materials and methods: A total of 12 implants will be placed in patients having mandibular free end- saddle areas selected from the outpatient section of the department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Alexandria University, after virtual implant planning with implant studio software, the implants will be inserted using stereolithographical design of surgical stent then measuring the deviation between the planned implant position before the surgery and the actual position of placed implant after surgical procedure. Results:Evaluation of the accuracy of placement was done by measuring the overall deviations between virtually planned and surgically placed dental implants.The mean of total angular difference in implant with stereolithographic stent were 10.9 ± 9.4°.While The Mean of total coronal differences in stereolithographic guided implant were 0.96 mm ± 0.7 mm.The Mean of total apical differences in stereolithographic guided implant were 1.8 ± 1.3 mm Conclusions: The stereolithographic surgical template was sufficiently accurate in transferring the planned implant position to the surgical field relative to the implant angulation and point of entrance.

Radiographic Evaluation of Two Different Designs for Treatment of Mandibular Bilateral Free End Saddle with Osseo-integrated Implants

Purpose: Thegoal of this study was to evaluate radiographically two different designs for mandibular freeend saddle with osseointegrated implants.Materials and Method: Ten lower Kennedy class I partially edentulous patients were selected to receiveimplant at the second molar area, then patients were divided into 2 groups according to the implantsuperstructures either (extra-coronal attachment or bar attachment). Patients of both groups receiveremovable partial denture of the same design. Patients were followed up for 0, 3, 6 and 9 months clinically.Results: Showed statistical difference between the 2 designs.Conclusion: It could be concluded that Tooth-implant supported partial denture may be reasonable andsimple solution for Kennedy class I partial denture.

Evaluation of piezotomed alveolar ridge splitting with stereolithographic surgical guide for implant placement (clinical study)

IntroductionNarrow dentoalveolar ridges remain a serious challenge for the successful placement of endosseous implants. Several techniques for this procedure may be considered, such as guided bone regeneration, bone block grafting, and ridge splitting for bone expansion. The ridge split procedure provides a quicker and a more reliable method. Advances in technology, Stereolithography allow fabrication of surgical guide from 3D generated models for precise implant placement. ObjectivesEvaluation of minimally invasive ridge splitting procedure aided with surgical guide. Materials and methodsA clinical study was performed on a total of 7 patients with mandibular free end saddle. The sample was selected conveniently to fulfill a list of inclusion and exclusion criteria. Then the selected participants performed ridge splitting with the aid of surgical guide. After ridge splitting, all patients had simultaneous implant placement followed by clinical and radiographical evaluation over a period of 6 months. ResultsMerging the preoperative, immediate and 6 months postoperative CBCT images showed statistically significant values of accuracy and increase in bone width and bone density. ConclusionAlveoalar ridge splitting with the aid of stereolithographic surgical stent is a well acceptable technique for implant placement.

The effectiveness of adhesives on the retention of mandibular free end saddle partial dentures: An in vitro study

ObjectivesExisting in vitro methods for testing denture adhesives do not fully replicate the complex oral geometries and environment; and in vivo methods are qualitative, prone to bias and not easily reproducible. The purpose of this study was to develop a novel, quantitative and more accurate model to test the effect of adhesives on the retentive force of mandibular free end saddle partial dentures. MethodsAn in vitro model was developed based on an anatomically accurate cast of a clinical case. Experimentally, the amount of adhesive was varied (0.2g–1g) and the tensile force required for displacement was measured. Different commercially available adhesives were then tested at the optimum volume using the in vitro model. A 3D finite element model of the denture was used to assess how the forces to induce denture displacement varied according to the position of the force along the saddle length. ResultsThe mass of adhesive was found to significantly alter retention forces, with 0.4–0.7g being the optimum range for this particular scenario. Use of adhesives significantly improved mandibular free end saddle partial denture retention with the worst performing adhesive increasing retention nine-fold whilst the best performing adhesive increased retention twenty three-fold. The finite element model revealed that 77% more force was required to displace the denture by positioning forces towards the mesial end of the saddle compared to the distal end. ConclusionsAn in vitro denture adhesive model was developed, which demonstrated that mass of adhesive plays a significant role in enhancing denture retention and supported the design principle of placing as few teeth as clinically necessary on the distal end of the free end saddles. Clinical significanceLimiting the position of teeth on free end saddles to the mesial and mid portion of the saddle will reduce displacements caused by mastication. The movement of mandibular free end saddle partial dentures can be restricted with the use of denture adhesives. Altering the mass of adhesive used can further improve the retention of mandibular free end saddle partial dentures for patients.

EVALUATION OF PIEZOTOMED ALVEOLAR RIDGE SPLITTING WITH STEREOLITHOGRAPHIC SURGICAL GUIDE FOR IMPLANT PLACEMENT

INTRODUCTION: Narrow dentoalveolar ridges remain a serious challenge for the successful placement of endosseous implants. Several techniques for this procedure may be considered, such as guided bone regeneration, bone block grafting, and ridge splitting for bone expansion. The ridge split procedure provides a quicker and a more reliable method. Advances in technology, Stereolithography allow fabrication of surgical guide from 3D generated models for precise implant placement. OBJECTIVES: Evaluation of minimally invasive ridge splitting procedure aided with surgical guide. MATERIALS AND METHODS: A clinical study was performed on a total of 7 patients with mandibular free end saddle. The sample was selected conveniently to fulfill a list of inclusion and exclusion criteria. Then the selected participants performed ridge splitting with the aid of surgical guide. After ridge splitting, all patients had simultaneous implant placement followed by clinical and radiographical evaluation over a period of 6 months. RESULTS: Merging the preoperative, immediate and 6 months postoperative CBCT images showed statistically significant values of accuracy and increase in bone width. CONCLUSIONS: Alveoalar ridge splitting with the aid of stereolithographic surgical stent is a well acceptable technique for implant placement.

The effect of some components on the rigidity of mandibular bilateral free end saddle dentures

One partially dentate person, his remaining teeth being 44, 43, 42, 41, 31, 32 and 33, was simultaneously provided with one maxillary complete denture and three mandibular free end saddle dentures having cobalt chromium alloy skeletons of different design. One denture was constructed with a lingual plate, another with a sublingual and a secondary bar, while on a third denture the major connector consisted of an enlarged secondary bar. On all the dentures occlusal rests were placed on teeth nos 44 and 33. Rosette strain gauges were placed in the midlines of all the major connectors. The gauges were calibrated on the master cast placed in a universal testing machine. The clinical recordings were taken from the gauges during one session under repeated loading conditions. Readings were repeated on one denture after removal of (1) the secondary bar and (2) the secondary bar and the occlusal rests. The recordings were used to calculate (1) the principal maximum and minimum strains and (2) the direction of the strains at the points of the bases beneath the centre of the gauges. The results show that studies of relevant functional deformation patterns of dentures can only be made in clinical experiments. Furthermore, they show that the base with an enlarged secondary bar exhibits more deformation than the other two types of base. Removal of the secondary bar did not significantly increase the deformation of the denture also equipped with a sublingual bar, neither did the removal of the occlusal rests. Both these changes, however, caused changes of the deformation patterns.

An Evaluation of the Occlusal Table Pattern in Bilateral Mandibular Free-end Saddle Type of Partial Denture in Relation to its Excursion during Mastication

An Evaluation of the Occlusal Table Pattern in Bilateral Mandibular Free-end Saddle Type of Partial Denture in Relation to its Excursion during Mastication

An analysis of stress distribution in the free-end saddles on the mandibular model.

This experiment was designed to investigate and evaluate the characteristic behavior of mandibular free-end saddle removable partial denture using various retainers. The abutment tooth displacement and saddle movement were measured while a known vertical force was applied on the saddle. Fifteen different types of free-end saddle dentures were tested, using four various types of prefabricated attachments. Strain-measuring devices were used to measure the extent of abutment tooth displacement and saddle movement. The findings were as follows: 1) The force transmitted to the abutment tooth and the residual ridge were affected by (a) the selection of direct retainers, (b) splinting of abutment teeth, and use of indirect retainers, and (c) the variation in size and shape of the occlusal table on the saddle. 2) The influences by direct retainers a) With use of a resilient joint, the stress was heavily loaded on the residual ridge directly under the direction of force. b) With the joint incorporating the vertical rock-preventing device, a heavy proportion of lateral force was transmitted to the abutment tooth. 3) Both the lateral stress on the abutment tooth and movement of the saddle were reduced more effectively by use of indirect retainers than by splinting of abutment teeth. 4) By reduction of the occlusal area in bucco-lingual dimension, the denture saddle was better stabilized and the lateral stress on the abutment tooth was reduced effectively.