ABSTRACT
Deep lingual undercut (LU) is commonly encountered in the posterior mandible, and is considered a risk factor in dental implants. In this study we investigated the value of data extracted from OPGs in predicting LU depth. Such predictors might be valuable in reducing the chance of lingual plate perforation (LPP) by recommending CBCTs prior to dental implant insertion when deep LU is anticipated We aimed at assessing the following variables as potential predictors of LU depth: 1) alveolar process height (measured on OPGs), 2) alveolar process width (measured on CBCTs), and 3) the distance from apical region of dental alveoli to superior margin of IAN canal (measured on OPGs). 128 CBCTs and corresponding OPGs of posterior mandibles of 128 patients (70 females, 58 males; age range=18-87 years, mean age=45.8 years, SD=17.0 years) were used. Only dentate sites of lower first (LM1) and second molars (LM2) were considered. Four predictors of LU depth were found, the strongest was the ratio between alveolar process width (which could be assessed clinically) and alveolar process height as measured on OPGs (r=.454 at LM1 site, r=.592 at LM2 site). Predictors derived from OPG measurements might be valuable in anticipating LU depth and might be more valuable when combined with alveolar process width (which might be assessed clinically). We recommend considering the suggested predictors in assessing the need of CBCT prior to immediate dental implant insertion in posterior mandible.
El socavado lingual profundo (SLU) se encuentra comúnmente en la porción posterior de la mandíbula y es considerado un factor de riesgo en los implantes dentales. En este estudio, investigamos el valor de los datos extraídos de los OPG para predecir la profundidad del SLU. Dichos predictores podrían ser valiosos para reducir la posibilidad de perforación de la placa lingual (PPL) recomendando CBCT antes de la inserción del implante dental cuando se anticipa un SLU. El objetivo consistió en evaluar las siguientes variables como posibles predictores de profundidad de SLU: 1) altura del proceso alveolar (medida en OPG), 2) ancho del proceso alveolar (medido en CBCT) y 3) la distancia desde la región apical de los alvéolos dentales al margen superior del canal IAN (medido en OPG). Se utilizaron 128 CBCT y las OPG correspondientes de mandíbulas de 128 pacientes (70 mujeres, 58 hombres; rango de edad = 18-87 años, edad media = 45,8 años, SD = 17,0 años). Sólo se consideraron los sitios dentados de los primeros molares inferiores (LM1) y los segundos molares inferiores (LM2). Se encontraron cuatro predictores de profundidad de SLU, el más fuerte fue la relación entre el ancho del proceso alveolar (que podría evaluarse clínicamente) y la altura del proceso alveolar medida en OPG (r = 0,454 en el sitio LM1, r = 0,592 en el sitio LM2). Los predictores derivados de las mediciones de OPG podrían ser valiosos para anticipar la profundidad de SLU y podrían ser más valiosos cuando se combinan con el ancho del proceso alveolar (que podría evaluarse clínicamente). Recomendamos considerar los factores predictivos sugeridos para evaluar la necesidad de CBCT antes de la inserción inmediata del implante dental en la porción posterior de la mandíbula.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Tongue/diagnostic imaging , Cone-Beam Computed Tomography , Mandible/diagnostic imaging , Tongue/anatomy & histology , Dental Implants , Alveolar Process/anatomy & histology , Alveolar Process/diagnostic imaging , Correlation of Data , Mandible/anatomy & histologyABSTRACT
Labial ridge undercut is more commonly seen in maxilla than mandible in completely edentulous individuals and it possess a great threat to the final estheticoutcome. Construction of a labial flange in conventional manner might compromise the facial support and muscles of facial expression, limit function, and compromise aesthetics for a better prognosis, an unconventional approach is needed for the construction of complete denture. This case report describesan innovative, economical, nonsurgical treatment option for fabrication of complete denture in a patient with a prominent labial undercut to enhance the facial aesthetics of the patient.
ABSTRACT
Introduction: Poor retention, stability and margin gap due to excessive bone lose following surgery is one of the major problems of rehabilitation in orbital defect with adhesive retained orbital prosthesis. Presentation of Case: This clinical report describes a simplified technique for the fabrication of an adhesive retained silicone orbital prosthesis by proper evaluation and using of remaining tissue undercuts to achieve ideal fit and aesthetics in a patient who has severely loss orbital bone after the surgery. Discussion: Aesthetics will be compromised if the proper evaluation of remaining tissue and treatment plan is not done prior prosthetic rehabilitation. To solve this issue sometimes maxillofacial prosthodontist may have to think for implant retained facial prosthesis. This is also sometime not possible due to several factors such as peri-implantitis, hygiene practice and dose of radiation etc. Conclusion: Proper use of remaining anatomical undercuts can be an alternative way to overcome the issue.
ABSTRACT
PURPOSE: The object of this clinical study was to evaluate the short-term outcome of modified resin-bonded fixed partial dentures which utilizes the original tooth undercuts and different path of insertion of components. MATERIALS AND METHODS: 71 units of modified RBFPDs that were used in 21 patients at the Department of Prosthodontics, College of Dentistry, Yonsei University were evaluated. The follow-up period was up to 25 months, the mean being 7 months. Survival rate, mobility, percussion, probing depth, bleeding on probing, plaque index was recorded and radiographs were taken to monitor alveolar bone loss. RESULTS & CONCLUSION: Within the limits of this short term retrospective study, it was concluded that: 1. No mechanical failure such as debonding or fracture of the framework was found during the follow-up period. 2. The periodontal apparatus was stable and no clinical change was observed after prosthetic treatment. 3. No significant marginal bone loss was found in the radiographic evaluation.
Subject(s)
Humans , Dentistry , Denture, Partial, Fixed , Follow-Up Studies , Hemorrhage , Organothiophosphorus Compounds , Percussion , Prosthodontics , Retrospective Studies , Survival Rate , ToothABSTRACT
STATEMENT OF PROBLEM: Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE: The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS: Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS: Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P .05). Group V had the highest mean MPa (N/mm2) (P .05). CONCLUSION: Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P .05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P < .05).
Subject(s)
Bicuspid , Biomechanical Phenomena , Cementation , Collodion , Dental Enamel , Denture, Partial, Fixed , Head , Intention , Molar , Phosphates , Prostheses and Implants , Retention, Psychology , Tooth , Tooth Preparation , Zinc Compounds , Zinc Phosphate CementABSTRACT
PROBLEM: The several studies were reported to the effects of individual tooth tray with the parallel tooth, but not reported to the effect of individual tooth tray with severe undercut in impression making. PURPOSE: The purpose of this study is to examine the effect of individual tooth tray; 1) the accuracy of impression in in terms of distance. 2) reproducibility of pocket. MATERIAL AND METHODS: In this study, a metal model with 3 teeth including tooth prepared 30-degree undercut and gingival crevice of the depth 5mm, width 0.4mm was cast. Impressions of the metal model were taken in 5 times used 4 kinds of impression materials with individual tooth tray and another impression taking were made with conventional method without individual tooth, used same materials, procedure. The stone models were made. Distances between abutments were measured with a Micromeasurescoup-mm. RESULT: The following results were obtained; 1. In the comparison of inter-abutment distance between parallel tooth without individual tooth tray, 4elastomeric materials have not significant difference to the metal model(p>0.05). 2. In the comparisonof inter-abutment distance with undercut tooth without individual tooth tray, 4elastomeric materials have a significant difference to the metal model(p0.05). 4. It is not true that the pressure of impression material with individual tooth tray increased to gingival sulcus. CONCLUSION: By the results, I knew the fact that individual tooth tray was useful impression method on the teeth with severe undercut for the dimensional stability. Also, I could not confirm the fact that individual tooth tray would increase the penetrating pressure into cervice.