Fahad Ata Siddiqui1, Abubakar Sheikh2, Syed Ajlal Akhtar3, Saqib Rashid4, Zohaib Khurshid5, Shariq Najeeb6
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Siddiqui F A, Sheikh A, Akhtar S A, Rashid S, Khurshid Z, Najeeb S. Radiographic Evaluation of Dentin Thickness and Pulp SpaceWidth for Different Age Groups. J Pak Dent Assoc. 2012: 01 (02); 99 – 102
To radiographically measure the thickness of dentin and width of pulp space for different age groups.
Non-pathological mandibular 2nd premolars with closed apices of 200 patients were evaluated radiographically using the Digora®radiographic imaging system. The sample was categorized into three groups; 15-29 years, 30-44 years and 45-59 years old. The dentin thickness and pulp space width were measured at different levels and recorded. SPSS version 13.0 was used for statistical analysis. One way ANOVA testing was done to statistically test the results. Level of significancewas kept at p value <0.05.
It was observed that the mean dentin thickness was highest at levelA; 4.45mm+-0.54 in the 15-29 year age group.Whereas, the dentin thickness was highest at level B for the other age groups i.e., 4.59mm +- 0.56mm (30-44 years) and 4.69mm+- 0.39 (45-59 years) respectively.However, the lowestmean dentine thickness of all age groups was found at level E. Moreover, readings at levels B, C and E were statistically significant p<0.05, suggesting continuous dentin deposition with age in all age groups. The results of pulp space analysis revealed that the highestmeanwidth of pulp space for age groups, 15-29 and 30-44was at level B; 1.13mm+-0.43 and 1.03mm+- 0.34 respectively.Whereas, the oldest age group (45-59) had the highest width of pulp space at levelA; 0.84mm+- 0.42. Furthermore, the lowestmeanwidth of pulp space of all the age groupswas seen at level Eand the resultswere statistically significant for all levels p<0.05 suggesting a reduction in pulp spacewidthwith age.
In this study dentin thickness and pulp space width have shown variation with age due to continued dentin depositionwhich can be a factor effecting the success of treatment for different groups, hence agespecific treatment tools should be developed.
entin is porous, fluid-filled mineralized tissue which supports the overlying enamel mechanically . Approximately 70% of mature dentine is made up of inorganic material, 20% organic material and 10% water by weight . In terms of hardness,dentin is slightly harder than bone and softer than enamel which can be appreciated on radiographs as dentin appears more radiolucent than enamel and more radiopaque than pulp . The elastic nature of dentin provides flexibility and prevents fracture of overlying brittle enamel . Cementum covers the dentin in the root of the tooth and the junction of cementum and dentin in humans is less distinct as they intermingle .
There are three different types of dentin; primary, secondary and tertiary dentin . Primary dentin forms until apex closure and tertiary dentin is formed in response to stimuli, such as trauma, attrition, caries or restorative dental procedures . However after the formation of primary dentin, the process of secondary dentin deposition continues throughout life although at a much slower rate comparatively and the greater deposition is on the roof and floor of the chamber Quantitatively, dentin has been analyzed through several different types of studies, a few of which were in relation to age, sex and restorative procedures of various types by employing different methods such as evaluation through radiographs, 3-D imaging, microscopy, histological and biochemical analysis There is lack of such data at the national level for different age groups irrespective of method. Therefore, this study will provide data reflecting the mean thickness of dentin and pulp space width for different age groups. This data would be useful for performing various restorative procedures.
This study was conducted at the Department of Endodontics, Fatima Jinnah Dental College and Hospital,
Karachi. It was a retrospective study and records of past 6 months i.e. Feb-July 2011 were evaluated. Nonprobability purposive sampling was used to select a total of 200 digital radiograph of patients referred to the Department of Endodontics. The sample was categorized into three groups; 15-29 years, 30-44 years and 45-59 years old.Mandibular 2nd premolarswith closed apices of patients aged 15-59 of either gender with no radiographic evidence of carious lesions, periodontal condition, noncarious
tooth loss or periapical pathosis were included in this study. Patients with history of parafunctional habits, trauma or any chronic medical condition were excluded from this study. The radiographs analyzed were taken using the paralleling technique. The digital images were captured by DIGORA® sensor (phosphor plate 2 cm x 3cm) which was placed in the pack of Classic DIGORA® Optime. Using the DIGORA® forWindows 2.7 software, image projection was completed. Dentin thickness and pulp space width were both measured, as discussed further. Dentine thickness along the long axis of tooth was measured at five different levels. Two readings were obtained at the crown level; one at the level of pulp horn
(A) and another at the cervical level (B) (fig a). Three readings were obtained at the root level. The root was divided into coronal (C), middle (D) and apical portion (E); a line was constructed from the external root surface to the external canalwall and readingswere taken fromthe center of each portion (fig b).
Measurements of dentin at all levels were obtained both from the mesial and distal aspects. Furthermore, the pulp space was simply calculated by subtracting the individual readings of dentin thickness of each side i.e. mesial and distal fromthe totalmesio-distalwidth of tooth at every level (A-E). The measurements were done by three different observers and the results were not known to each other. Mean readings of all observers were obtained and recorded in a preformed tabulated proforma and statistically evaluated using SPSS version 13.0. The level of significance was tested by one way ANOVA test.
A total number (N) of 200 radiographs were evaluated. Thenumber of radiographs evaluated in the 15- 29 year age group was 66, whereas the number of radiographs in the 30-44 year age group was 70 and there were 64 radiographs which fell under the 45-59 year age group. Means of dentin thickness and pulp space width both at five different levels were calculated. It was observed that mean dentin thickness in the youngest age group 15-29 was highest at level A;4.45+-0.54 and the lowest at level E;2.62mm+-0.42. However, the mean dentin thickness in age groups 30-44 and 45-59 was highest at level B; 4.59mm+-0.56 and 4.69mm+-0.39 respectively, and the lowest mean dentin thickness for these groupwere at level E; 2.89mm+-0.37 and 2.90mm+- 0.65 respectively.(TableNo 1)
Results of pulp width space measurements revealed, that the highestmeanwidth of pulp space of age group 15- 29 and 30-44 were at level B; 1.13mm+-0.43 and 1.03mm+-0.34 respectively. Whereas the highest mean width of pulp space of age group 45-59 was at level A; 0.84mm+-0.42. However, the lowest mean width of pulp space of all age groupswas observed at level E.The results at every level (A-E), of all age groups were statistically significant p <0.05, suggesting a reduction in pulp space widthwith age. (TableNo 2)
Dentin-pulp complex like all body tissues goes through changes with time. Reduction in the size of pulp chamber due to increased deposition of secondary dentin is the most evident change which have been quoted in a number of studies, the results (table 1 and 2) of which are consistent with this study . The continuous process of dentin deposition with age was observed at all defined levels in this study on the radiographs. However maybe due to variable rates of secondary dentin formation on different sites , the results for dentin thickness measurement in the coronal regionwere not significant for level A; at the level of pulp horn. Literature supports the high rate of secondary dentin formation at the roof and floor of the chamber and the floor of the chamber anatomically coincide with the level of the CEJ (B) (17).
Statistical analysis revealed significant increase in dentin thickness and reduction in the size of pulp chamber with age at this level (p < 0.05). Measurements taken from the radicular portion revealed significant differences for dentine thickness of different age groups at levels D (middle) and E (apical) (p < 0.05); however results obtained from levelC (coronal)were insignificant. These results confirmthe findings of some previous studies. In contrast to dentin thickness, measurements for width of pulp space in coronal and root portion revealed significant results for all age groups at all defined levels i.e.A-E, suggesting a reduction in sizewith increasing age (p < 0.05). The results are similar to findings of other studies carried out in previous years Restorative procedures such as tooth preparation for restorations such as crown and deep class II cavity may render the tooth to risk of pulp exposure and extensive loss of tooth structure . In this study,measurements taken at pointsAand B reveals that in the first age group i.e. 15-29 years, chances of pulp exposure, during procedures requiring removal of tooth structure in the coronal aspect are more compared to the other age groups; 30-44 and 45- 59 respectively, due to the variation in dentin thickness and pulp spacewidth (table 3, 4). In younger patients, pulp chambers are large due to lesser secondary dentin deposition as compared to the older patients and hence care must be taken by the clinician during crown and cavity preparations to avoid pulp exposure. During preparations for crown, hand piece generates heat, which if the dentin thickness is less than 1mm can cause thermal injury to pulp . As depth of cut dentin increases irrespective of any procedure, the pulp becomes prone to chemical, physical and microbial irritants due to increase in permeability of dentin and can lead to adverse effects such as pulp necrosis . The permeability of dentin decreases with time as the physiological process of secondary dentin deposition continues In root canal treatment, access and canal negotiation presents the greatest challenge in course of the procedure for older patients .According to the findings of George G Phillipas in 1961, the highest deposition of secondary dentin is on the floor of the pulp chamber and the results of this study confirms his findings (table 1 and 2) . The amount of dentin at the level of floor of pulp chamber appears to be the main reason for difficulty in locating canals in older patients compared to younger ones relatively . Along with narrowing of the pulp due to secondary dentinewith age, the pulp is replaced by fibrous tissue; a process called pulp fibrosis and presents the clinicianwith challenges in negotiating the canal16 .
Clinicians must deny the “one-fit for all” approach, which would help improve the success rate of procedures and contribute in improving the quality of treatment. Further research is required from treatment point of view to evaluate the outcome of treatment in different age groups with different variables in order to establish agespecific protocols.
The limitations of this study are related to the accuracy and reliability of themethod used as radiographs are two-dimension representation of a three-dimensional tooth structure. However the aim of this study was not mathematical rather reference based and the mean values can be used as a reference point for different levels.
In this study dentin thickness and pulp space width have shown variation with age due to continued dentin deposition which can be a factor effecting the success of treatment for different groups, hence age-specific treatment protocols should be developed
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