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 Table of Contents  
ORIGINAL ARTICLE
Year : 2009  |  Volume : 9  |  Issue : 3  |  Page : 148-150

Complete denture fractures: A clinical study


Department of Prosthodontics, Teerthanker Mahaveer Dental College Moradabad, Uttar Pradesh, India

Date of Web Publication14-Oct-2009

Correspondence Address:
Amit V Naik
c/o Dr V P Naik, 3141, Khade Bazar, Belgaum, Karnataka-590 001
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-4052.57084

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  Abstract 

The main purpose of the study was to determine the causes for the fracture of complete dentures of patients reporting to the Department of Prosthodontics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India. Data collected from 200 patients reported for repair of their complete dentures. Data was collected from patients, aged between 30 to 80 years (mean 55 plus/minus 25 years), from both the genders. Investigations were done on factors causing the fracture. After the analysis it was observed that the ratio of fracture of upper to lower denture was 1:3. Most fractures were common among males (55%). The most common reason being accidental dropping of the denture in case of the lower and improper fit and stability of the denture, improper arrangement and occlusion of the teeth for the upper one. Midline fracture was the most common site of fracture (60%). After analysis, the causes for the fracture were divided into material factors and clinical/ technical factors. It was concluded that the after denture delivery, instructions of denture care were required to reduce mishaps, proper principles of denture construction were required for mechanical advantage of the denture - balanced occlusion, removal of interferences, reduction of stress concentration areas, etc has to be followed. The use of high impact acrylics and strengthened acrylic along with methods increasing fracture toughness of the conventional acrylic dentures are to be used.

Keywords: Acrylic, complete denture fracture, prosthodontics


How to cite this article:
Naik AV. Complete denture fractures: A clinical study . J Indian Prosthodont Soc 2009;9:148-50

How to cite this URL:
Naik AV. Complete denture fractures: A clinical study . J Indian Prosthodont Soc [serial online] 2009 [cited 2019 Nov 15];9:148-50. Available from: http://www.j-ips.org/text.asp?2009/9/3/148/57084


  Introduction Top


The life of a complete denture wearer is abruptly paralyzed by the sudden fracture of his/her denture which is of utmost necessity for his/her day to day routine life. As part of the dental education faculty, it is always our goal to make the life of denture-wearers easier and happier by investigating and solving the problems related to complete denture patients. As literature suggests, there are many causes and reasons associated with fractures of complete dentures. This study was undertaken to investigate the causes of denture fracture and device ways of reducing these problems in the future.


  Materials and Methods Top


This study was conducted in the Dept of Prosthodontics, Teerthanker Mahaveer Dental College and Research Center, Moradabad, India. Data was collected for one year from 200 complete denture patients who reported for the repair of their dentures due to fracture of the denture. The data was categorized with the following parameters separately for upper and lower dentures:

  1. Age and gender of the patient
  2. Aage of the denture
  3. Reason for the fracture, according to history, given by the patient and clinical analysis of the clinician.
  4. Site of the fracture


A detailed history of the fracture was taken from the patient and the denture was assessed for retention, stability, occlusal errors,etc by the clinician. The data collected was analyzed using chi square test and the result was considered statistically significant when probability was less than 0.05.


  Results Top


In this study, 200 complete dentures were examined, excluding removable partial dentures and debonded teeth. [Table 1] and [Table 2]

It was observed that the ratio of fracture of upper denture to lower denture was 1:3 [Table 3].

Maximum fracture was seen in the denture age group of two to four years post- delivery followed by zero to two years.

Accidental dropping of the denture while cleaning, insertion and removal (53%) was the most common cause for lower denture fracture followed by poor retention and fit (22%) whereas poor fit was the most significant factor for upper denture fracture (43%) followed by accidental dropping of the denture (25%)

Midline fracture was most common in both the upper and lower dentures (more than 60%).

[TAG:2]Discussion[/TAG:2] In this study, midline fracture was the most common site of fracture (more than 60%). Midline fracture results from cyclic deformation of the base during function. Since lower dentures fractured it was postulated that the less surface area and thinness in the middle part of the denture are responsible for the fracture. Also, patient negligence during insertion, removal and cleaning of the denture are the major causative factors. Accidental dropping of the denture was the prime cause in these cases, the lower being the delicate of the two was fractured in the ratio of 3:1 to the upper. Presence of deep incisal notches, diastema and thin labial flanges for esthetics and comfort factors of the patient act as stress raisers and contribute to midline fracture of the maxillary denture. Poor fit was the prime cause in upper denture fracture, such dentures flex in the mouth during function around the midline and due to repeated small loadings during mastication lead to the fatigue fracture. This study also holds good with the study of Beyli and von Fraunhofer [1] who suggest the poor fit is the main culprit. Mathews and Wain [2] show that tensile stresses are on the palatal aspect of the denture.

The other causes of fracture are poor occlusion (16% in upper, 12% lower). Many of the dentures in the study opposed natural dentition and most of the sets were not balanced occlusally leading to unwanted stresses in the weaker parts of the denture. Heavy occlusal contacts from the natural teeth and over-erupted natural teeth lead to strong forces and caused constant interferences in the masticatory movements. Faulty teeth setting outside the ridge may concentrate stresses on non-stress bearing areas of the denture.

From studies of Beyli and Smith, [3] it is clear that internal defects in the acrylic denture base like voids, porosities, notches, scratches, residual stresses are predominant factors in the fracture of the denture. These areas of stress concentration lead to crack formation and propagation.

Inherent properties of the denture base material also play a very important role in impact strength of the denture. Fractures from accidental droppings can be prevented to a large extent by using high impact resins, metal reinforcement (in the form of plates, wires and fillers) and, glass fibers in the form of woven mat. Reinforcement with glass fibers enhances the mechanical strength characteristics of denture bases such as the transverse strength, ultimate tensile strength, and impact strength. The technical work of fabricating acrylic dentures using modern techniques which reduce voids and porosities releasing residual stress is a must.

Material breakdown with age and water sorption will reduce the fatigue resistance of the material. Hence selection of the material for denture requires more emphasis.

The study showed that maximum denture fractures are in the group of two to four years post-delivery followed by zero to two years. According to Hargreaves, [4] physical properties of acrylic do not deteriorate with age, but the clinical function may induce stress which after a period of usage may bring deterioration of the material and hasten fracture.


  Conclusion Top


From this study, the following conclusions can be drawn:

  • Proper patient education and motivation of patients using dentures to reduce accidental mishaps.
  • Following definite prosthodontic principles in denture construction - analyzing proper fit and retention of the denture. Eliminating occlusal interferences and establishing balanced occlusion
  • Using high impact polymers, metal reinforcements, glass fibers
  • Using processing techniques which reduce chances of voids and porosities.
  • Maintaining proper thickness in flanges and incisal notch areas to prevent stress concentration.
Inducing methods of research for manufacture of high strength material which can reduce the denture fractures.[19]

 
  References Top

1.
Beyli MS, Von Fraunhofer JA. An analysis of causes of fracture of acrylic resin dentures. J Prosthet Dent 1981;46:238-41.  Back to cited text no. 1
[PUBMED]  [FULLTEXT]  
2.
Matthews E, Wain EA. Stresses in denture bases. Br Dent J 1965;100:167-71.  Back to cited text no. 2
    
3.
Smith DC. The acrylic denture: Mechanical evaluation mid-line fracture. Br Dent J 1961;110:257-67.   Back to cited text no. 3
    
4.
Hargreaves AS. The prevalence of fractured dentures. Br Dent J 1969;126:451-5.   Back to cited text no. 4
[PUBMED]  [FULLTEXT]  
5.
Jagger DC, Harrison A, Jandt KD. The reinforcement of dentures. J Oral Rehabil 1999;26:185-94.   Back to cited text no. 5
[PUBMED]  [FULLTEXT]  
6.
Darbar UR, Huggett R, Harrison A. Denture fracture: A survey. Br Dent J 1994;176:342-5.   Back to cited text no. 6
[PUBMED]  [FULLTEXT]  
7.
Wiskott HW, Nicholls JI, Belser UC. Stress fatigue: Basic principles and prosthodontic implications. Int J Prosthodont 1995;8:105-16.   Back to cited text no. 7
[PUBMED]  [FULLTEXT]  
8.
Jagger DC, Harrison A. The fractured denture-solving the problem. J Primary Dent Care 1998;5:159-62.   Back to cited text no. 8
    
9.
Kydd WL. Complete base deformation with varied occlusal tooth form. J Prosthet Dent 1956;6:714-8.   Back to cited text no. 9
    
10.
Lambrecht JR, Kydd WL. A functional stress analysis of the maxillary complete denture base. J Prosthet Dent 1962;12:865-72.   Back to cited text no. 10
    
11.
Rees JS, Huggett R, Harrison A. Finite element analysis of the stress concentrating effect of fraenal notches in complete dentures. Int J Prosthodont 1990;3:238-40.   Back to cited text no. 11
[PUBMED]  [FULLTEXT]  
12.
Yunus N, Harrison A, Huggett R. Effect of microwave irradiation on the flexural strength and residual monomer levels on an acrylic repair material. J Oral Rehabil 1994;21:641-8.   Back to cited text no. 12
[PUBMED]  [FULLTEXT]  
13.
Uzun G, Hersek N, Tincer T. Effect of five woven fiber reinforcements on the impact and transverse strength of a denture base resin. J Prosthet Dent 1999;81:616-20.   Back to cited text no. 13
    
14.
Vallittu PK. Comparison of the in vitro fatigue resistance of an acrylic resin removable partial denture reinforced with continuous glass fibers or metal wires. J Prosthodont 1996;5:115-21.   Back to cited text no. 14
[PUBMED]  [FULLTEXT]  
15.
Vallittu PK, Lassila VP, Lappalainen R. Transverse strength and fatigue of denture acrylic-glass fiber composite. Dent Mater 1994;10:116-21.   Back to cited text no. 15
[PUBMED]  [FULLTEXT]  
16.
Kim SH, Watts DC. The effect of reinforcement with woven E-glass fibers on the impact strength of complete dentures fabricated with high-impact acrylic resin. J Prosthet Dent 2004;91:274-80.   Back to cited text no. 16
[PUBMED]  [FULLTEXT]  
17.
Polyzois GA, Andreopoulos AG. Acrylic resin denture repair with adhesive resin and metal wires: Effects on strength parameters J Prosthet Dent 1996;75:381-7.  Back to cited text no. 17
    
18.
Barpal D, Curts DA, Finzen F, Perry J, Gansky SA. Failure load of acrylic resin denture teeth bonded to high impact acrylic resins J Prosthet Dent 1990;80:666-671  Back to cited text no. 18
    
19.
Jameson WS. Fabrication and use of a metal reinforcing frame in a fracture prone mandibular complete denture. J Prosthet Dent 2000;83:476-9.  Back to cited text no. 19
[PUBMED]  [FULLTEXT]  



 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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Abstract
Introduction
Materials and Me...
Results
Discussion
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