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At least 109 records · Page 6Linked to original sources
PubMed1999

Continued apexogenesis of immature permanent incisors following trauma.

Two cases of trauma to immature teeth are described which differed significantly in their initial severity. However, both subsequently presented with continued apical root formation. In the two cases a histological examination after tooth removal confirmed continued apical development of the traumatised immature teeth distant to their respective coronal portions. These cases highlight the resilience of the root sheath of Hertwig to trauma.

Adolescent↗
PubMed1997

Use of calcium hydroxide for apical barrier formation and healing in non-vital immature permanent teeth: a review.

OBJECTIVE: To review the use of calcium hydroxide for induction of apical barrier formation and healing in immature permanent teeth. INTRODUCTION: Pulp necrosis is a frequent complication of dental trauma in immature permanent teeth. Endodontic treatment of these teeth is often complicated. The walls of the root canals are frequently divergent and the apices immature, making debridement and obturation difficult. The aim of treatment is induction of apical healing which may be defined as apical closure through formation of mineralised tissue and repair of the periapical tissues. Calcium hydroxide is the material of choice for apical barrier formation and healing. RESULTS: The use of calcium hydroxide for apical barrier formation is successful in 74-100% of cases irrespective of the proprietary brand used. The average length of time for apical barrier formation is approximately 5 to 20 months. Control of infection and adequate cleaning of the root canal are very important for apical healing. CONCLUSIONS: While the success rate of apical barrier formation using calcium hydroxide is high, long-term follow-up of these teeth is necessary. Problems such as failure to control infection, recurrence of infection and cervical root fracture may occur. The latter is more frequent in immature luxated teeth with the least root development.

Bacterial Infections↗
PubMed2005

Endodontic treatment for children.

Root canal treatment for children has particular difficulties and considerations. It must be planned in light of the remaining teeth, and the need for balancing or compensating extraction borne in mind. Diagnosis may be difficult, as may prolonged treatment under local anaesthesia and rubber dam. Vital pulpotomy techniques with formocresol and/or calcium hydroxide must be carefully executed in line with the UK National Guidelines. The treatment of the avulsed tooth has been the subject of much research, and practitioners should ensure that they are up-to-date with current treatment modalities.

Child↗
PubMed2005

Weakened anterior roots--intraradicular rehabilitation.

This paper highlights the fact that many anterior teeth requiring restoration are severely weakened having wide, flared canal spaces, and thin dentinal walls that are prone to fracture. Traditionally these teeth have been restored using metal posts and are often unsuccessful because of lack of retention or root fracture. This paper describes how mineral trioxide aggregate (MTA) can be used to form an immediate apical seal rather than waiting months for apexification. Weakened roots can be reinforced using dentine bonding agents and composite resin and if insufficient coronal tooth structure is present a quartz-fibre post can be placed to retain a composite core.

Aluminum Compounds↗
PubMed1999

Dental students' ability for three-dimensional perception of two-dimensional images using natural stereopsis: its impact on radiographic localization.

OBJECTIVES: To investigate the ability of dental students to perceive 2D images in 3D using natural stereopsis and to evaluate whether the use of stereovision influences their interpretation of radiographic depth, with particular reference to intra-oral radiographs of third molars compared with scanograms. METHODS: Seventy-two dental students (37 from sixth semester and 35 from fourth semester) who had all completed a course in the use of the buccal-object rule participated in the study. Lectures in 3D perception were given to the sixth semester students. They were trained in 3D perception using a 'single image colour field' stereogram and classical stereograms of circles. Both semester students diagnosed nine scanograms and nine intra-oral radiographs for: (1) the position of the crown of an impacted third molar in relation to the second molar and (2) root deviations in the bucco-lingual plane. The sixth semester students recorded whether they were able to achieve a 3D image in these cases. RESULTS: Five students could not achieve a depth image from the training stereograms. Fifty-six per cent agreed on which two objects in the circles were nearest to the viewer and which were most distant, whereas 38% agreed on the opposite. Root deviation was a more difficult diagnostic task than crown position, and the sixth semester students made significantly more correct diagnoses than the fourth semester students (P < 0.001). Irrespective of semester, there was no significant difference between number of correct diagnoses of crown alignment in intra-oral radiographs and scanograms (P = 0.57), whereas root deviations were diagnosed significantly more accurately from the intra-oral radiographs (P < 0.001). CONCLUSIONS: Most dental students can be taught to use natural stereovision to achieve a 3D image from two radiographs at different angles. 3D image is achieved equally well from intra-oral radiographs with a free-hand tube shift and scanograms. Those students who achieved a 3D image in a particular case, made more correct diagnoses than those who could not.

Adult↗
PubMed1999

The effect of periapical rarefying osteitis on cortical and cancellous bone. A study comparing conventional radiographs with computed tomography.

OBJECTIVE: To determine whether erosion of the cortical plate is necessary for successful radiographic identification of periapical rarefying osteitis. METHODS: Forty-two periapical osteitic lesions were diagnosed from periapical radiographs of 26 patients who were subsequently examined by cross-sectional computed tomography (CT). The relation of the lesions to the buccal and lingual cortical plates was determined and their size measured. RESULTS: The 42 lesions varied in size from 2 - 10 mm. Thirty one (74%) lesions diagnosed on the periapical radiographs were limited on CT to the cancellous bone with no erosion of the cortical plates. The 11 lesions with cortical erosion were randomly located throughout the jaws. Erosion was due to either the eccentric buccal or lingual location of the tooth apex, large size (>6 mm) of the lesion or narrowness of the jaw. CONCLUSIONS: Periapical lesions can be diagnosed from periapical radiographs while they are limited to the cancellous bone and before they have eroded the cortices.

Adolescent↗
PubMed2000

Comparison of three intra-oral storage phosphor systems using subjective image quality.

OBJECTIVE: To compare the subjective image quality of three intra-oral storage phosphor systems. METHODS: DenOptix (Dentsply/Gendex, Chicago, IL, USA), Digora (Soredex, Helsinki, Finland), and CD-Dent (DigiDent Digital Imaging Technologies, Nesher, Israel) were compared. Two different imaging plates (IPs), BAS300 and HR300 (Fuji Photo Film Co., Tokyo, Japan) were used with the DenOptix system. The specimen was the maxilla and surrounding soft tissues of an adult cadaver. Imaging was at 70 kVp and 8 mA with a focus-detector distance of 38 cm using an optical bench. The exposure times were varied and a panel of five dentists independently evaluated the images produced with each system/IP receptor for seven features; proximal caries, gingival soft tissues, cortical bone, root canal space, root apices, periodontal ligament space and endodontic instrument clarity on a three-interval confidence scale. The best three exposures were chosen according to the highest scores for each system. These images were re-read in random order a total of 10 times. Pair-wise comparisons were made by use of odd's ratio analysis. A 95% confidence interval was applied. RESULTS: Images made with the DenOptix system/BAS IP combination were perceived to have the best overall image quality. The DenOptix/HR IP combination and Digora were rated almost equally in second place. The DigiDent system was ranked inferior. The Digora was considered to be the best for demonstrating gingival soft tissues (P < 0.05) and the DenOptix/HR300 combination the best for clarity of endodontic instruments (P < 0.05). CONCLUSIONS: While the DenOptix/BAS 300 combination was rated highest overall, the ranking of image quality by modality was found to be task-dependent. Digora was rated best for demonstrating gingival soft tissues.

Adult↗
PubMed2001

Detection of simulated internal tooth resorption using conventional radiography and subtraction imaging.

OBJECTIVES: To compare the diagnostic accuracy of conventional radiography with digital subtraction imaging in the detection of simulated internal resorption. METHODS: Simulated resorption cavities were created by the sequential use of progressively larger round burs (ISO size range 006-016) in the labial wall of the coronal or apical thirds of the pulp chamber of the maxillary incisors of two cadavers. Five viewers examined 120 pairs of radiographs, one of each pair being baseline (no lesion) and the other with or without a lesion. The process was then repeated with subtraction images of the pairs of radiographs. Receiver Operating Characteristic (ROC) analysis was used to compare the diagnostic accuracy of the two imaging modalities. RESULTS: Using conventional radiography, the minimum lesion size detectable coronally was in the 'medium' range (ISO size 010 and 012 round burs), but only 'large' lesions (ISO size 014 and 016) could be detected in the apical region. The overall diagnostic accuracy of subtraction imaging was superior to conventional radiography but only significant (P<0.05) for coronal lesions. CONCLUSION: Subtraction radiography may be a useful tool for detecting and monitoring the progress of internal root resorption.

Cadaver↗
PubMed2001

Assessment of root resorption and root shape: periapical vs panoramic films.

A radiographic examination is an essential part of the diagnostic process in orthodontics. However, what radiographs are needed to properly evaluate root shape and position? Most clinicians order panoramic or periapical radiographs in addition to the cephalometric radiograph. The purpose of this study was to find out whether one type of film is more accurate than the other in the pretreatment evaluation of root shape and the posttreatment computation of apical root resorption. Pretreatment and posttreatment panoramic films and full-mouth periapical films from 42 patients who completed fixed orthodontic treatment were assessed for tooth length and root shape. Panoramic films showed significantly greater average apicaL root resorption than periapical films for the 743 teeth surveyed. The greatest differences were found in the lower incisors, the least in the maxillary incisors. Classification of root shape was significantly different between the 2 types of radiographs. Root dilacerations and other abnormal shapes, clearly visible on periapical films, often appeared normal on panoramic films. The findings strongly suggest that root shape is much harder to assess on panoramic films. We conclude that, in cases where the apices are obscured or other factors are present that might suggest higher risk for root resorption or vertical bone loss, periapical films should be ordered. The use of panoramic films to measure pre- and posttreatment root resorption may overestimate the amount of root loss by 20% or more.

Adolescent↗
PubMed2002

Stress distribution produced by correction of the maxillary second molar in buccal crossbite.

The purpose of this study was to evaluate the stress distribution produced in the dentoalveolar system by a maxillary posterior crossbite appliance used for the correction of maxillary second molars in buccal crossbite. A photoelastic model was fabricated using a photoelastic material (PL-3) to simulate alveolar bone and ivory-colored resin teeth. The model was anteriorly and posteriorly observed with a circular polariscope and photographically recorded before and after activation of the maxillary posterior crossbite appliance. An uncontrolled palatal tipping and a rotating force were generated when the traction force was applied on the palatal surface of the maxillary second molar. A controlled tipping and an intrusive force were generated when the traction force was applied on the buccal surface of the maxillary second molar.

Alveolar Process↗
PubMed2004

A comparison of three methods to accurately measure root length.

Measuring the severity of root shortening after orthodontic treatment is a common problem in the dental fields as well as in litigation, legislation, and the ethics arena. The most common method to evaluate root length shortening is by using periapical radiographs. Surprisingly, root elongation after orthodontic treatment in adult patients was reported in the past. The aims of this study were to measure the effects of angular changes between the tooth and the film on the length of the image of a tooth model, to compare three methods to accurately measure root length in different films, and to find the most accurate reference points on the tooth for calculating root lengths. Five amalgam dots were placed on an acrylic model of a maxillary central incisor: ie, most apical, most incisal, mesial CEJ, distal CEJ, and most apical CEJ on the buccal side. The tooth model was placed in a special jig and radiographed at four different film-to-tooth angulations. Root and crown lengths were measured on both the model itself and on a computer monitor displaying the image that resulted from scanning the film into the computer. The results revealed that angular changes between the tooth and the film affect the measured tooth length. The midpoint between the mesial CEJ point and the distal CEJ point (median CEJ) was the best reference point for measuring root length. This was true when the calculations were done with the rule-of-three formula.

Adult↗
PubMed2005

Apical root resorption of maxillary first molars after intrusion with zygomatic skeletal anchorage.

The aim of this study was to evaluate radiographically the apical root resorption of maxillary first molars after their intrusion was done using zygomatic miniplates as skeletal anchorage in open-bite cases. The study group comprised 16 consecutively treated open-bite cases who had received special titanium miniplates in their zygomatic bones for use as anchorage to apply orthodontic intrusive forces to the maxillary posterior region. The control group consisted of 16 patients, who were matched regarding age, sex, and treatment duration but who had undergone fixed orthodontic treatment without intrusion mechanics for molars. Tooth lengths were measured on pretreatment, and posttreatment panoramic radiographs of all patients and mesiobuccal and distobuccal roots of left and right maxillary first molars were measured on-screen using a software program. The difference between the pre- and posttreatment tooth lengths was defined as apical root resorption. Comparison of the differences in root resorption of the two groups using the t-test for independent samples showed a statistically significant difference (P = .004) only for mesial roots on the right side. But because the mean difference in apical root resorption was only 0.5 mm, it was concluded that the apical root resorption of maxillary first molars after intrusion was done using zygomatic skeletal anchorage was not clinically significant.

Adolescent↗
PubMed2005

Root resorption after orthodontic intrusion and extrusion: an intraindividual study.

The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight weeks. Eleven maxillary first premolars from six randomly selected orthodontic patients served as controls. Root resorption was determined using scanning electron microscopy. Quantitative assessment of the percentage of resorbed area of the total root surface was performed on composite micrographs. The severity of root resorption was also assessed by visual scoring of the roots. Root resorption mainly occurred at the apical part of the roots in both experimental groups. A significant difference in root resorption was found between the intruded and the control teeth (P = .006) but not between the extruded and the control teeth. However, the mesial and distal root surfaces showed resorption on 5.78 +/- 3.86% of the root surface of the intruded teeth and 1.28 +/- 1.24% of the root surface of the extruded teeth, and this difference was significant (P = .004). In addition, a large individual variation was found. From this study, it can be concluded that intrusion of teeth causes about four times more root resorption than extrusion. Because the amount of root resorption due to intrusion or extrusion in the same patient is correlated, every clinician should be aware that the extrusion of teeth might also cause root resorption in susceptible patients.

Adolescent↗
PubMed2005

Association between growth stunting with dental development and skeletal maturation stage.

The aim of this study was to determine the influence of growth stunting on the maturation stage of the medium phalanx of the third finger (MP3) and the dental development of the left mandibular canine in 280 high school children (140 stunted and 140 normal controls; equally distributed by sex) between 9.5 and 16.5 years of age, from a representative Peruvian school. Periapical radiographs of the MP3 from the left hand were used to determine the skeletal maturity stage, according to an adaptation of the Hägg and Taranger method. Panoramic radiographs were used to determine the dental maturity stage of the lower left canine, according to Demirjian method. Stunting was determined by relating height and age, according to the World Health Organization recommendations. There was no statistically significant difference in the skeletal maturation stage (P = .134) and the dental development stage (P = .497) according to nutritional status, even when considering different age groups (P > .183). A high correlation (r = 0.85) was found between both maturity indicators regardless of the nutritional status (growth stunted, r = 0.855 and normal controls, r = 0.863) or sex (boys, r = 0.809 and girls, r = 0.892). When skeletal level was considered, correlations values were similar between advanced (r = 0.903) and average (r = 0.895) maturers but lower (r = 0.751) for delayed maturers. Growth stunting was not associated with dental development and skeletal maturity stages in Peruvian school children.

Adolescent↗
PubMed1999

Human teeth with periapical pathosis after overinstrumentation and overfilling of the root canals: a scanning electron microscopic study.

AIM: The aim of this study was to determine whether overinstrumentation followed by immediate overfilling could be a potential risk in the treatment of infected root canals. METHODOLOGY: Thirty-five human teeth with infected root canals were overinstrumented and overfilled approximately 45 min after their extraction. The experimental teeth were enlarged up to size 40 and the overinstrumentation and overfilling were checked with the aid of a magnifying glass. The specimens were fixed in glutaraldehyde plus sodium cacodylate solution and prepared for scanning electron microscope examination. RESULTS: Bacteria were detected on the flute of the files and mostly at the root apices around the main foramen, remaining firmly attached to resorptive lacunae despite the fact that the apices had undergone great changes, including fracture or zipping. A control group consisting of 10 human teeth root canals containing vital pulps were also overinstrumented and overfilled. No bacteria were detected on the flutes of the files, at the apices or on the extruded master cone overfilling these samples. CONCLUSIONS: The high percentage of bacteria adhering to the resorptive lacunae or in the flutes of files used in overinstrumented human teeth with infected root canals carry a potential risk for postoperative pain, clinical discomfort and flare-ups. The hazards observed in these circumstances do not support the one-visit treatment of teeth having acute or chronic periapical abscesses.

Bacteria↗
PubMed2000

A comparison of the relative efficacies of four hand and rotary instrumentation techniques during endodontic retreatment.

AIM: The purpose of this study was to quantify the amount of remaining gutta-percha/scaler on the walls of root canals when two engine-driven instruments (Quantec and ProFile) and two hand instruments (K-file and Hedström file) were used to remove these materials. The amount of apically extruded debris and the time required for treatment were also recorded. METHODOLOGY: One hundred extracted mandibular premolars were prepared using a modified step-back, flare technique and obturated with the lateral condensation technique. After repreparation with the test instruments, the specimens were cut transversally at the cervical, middle and apical thirds with steel discs and the three sections were split longitudinally. The amount of residual debris on the canal walls in each section was examined using a stereomicroscope. RESULTS: In all groups the cervical and middle thirds showed no debris. In the apical third, obturating material was observed in some specimens. No statistically significant difference was found between the two groups for incidence of debris, although the Hedström group showed a greater number of samples with remaining gutta-percha/sealer. When analysing dirty specimens only, there was a statistically significant difference between the four groups (P < 0.01) with the Hedström group having significantly less length of canal wall with remaining obturation material than the Quantec group. There was no significant difference amongst the groups for weight of extruded debris. However, there was a significant difference amongst the groups for mean treatment time with the Hedström file group requiring significantly less time than the Quantec group (P < 0.001); no significant differences were found between the other groups. Six instruments fractured in the Quantec group, four in the ProFile group, two in the Hedström group and two in the K-type group. CONCLUSIONS: The results showed that overall, all instruments may leave filling material inside the root canal. During retreatment there is a risk of instrument breakage, especially rotary instruments.

Analysis of Variance↗
PubMed2000

Detection of a transitional ion concentration zone during electronic measurement of root canal length: a study in vitro.

AIM: The aim of this study was to examine the importance of a transitional ion concentration zone at the apical foramen during electronic root canal length measurement (ERCLM). METHODOLOGY: The model comprised 21 extracted single-rooted human teeth, divided into two experimental groups and one control group, each of seven teeth. The anatomical tooth length was determined from the site of reference on the tooth crown to the canal orifice and was measured using an endodontic file and a vernier caliper. Two aqueous solutions of various NaCl, KCl and CaCl2 concentrations were mixed with agar. The Na+, K+ and Ca++ concentrations corresponded to the average value of each group as determined by atomic spectrophotometry evaluation of the extirpated human pulps. The agar containing cations was injected into the root canals after their preparation to a foramen diameter of 0.70 mm. The control teeth were then completely immersed in agar having the same concentration of cations as the agar inside the canal. In the first experimental group (group 1), the teeth were immersed in agar so that the ion concentration was higher inside the canal; in the second experimental group (group 2), the concentrations were reversed. In all three groups, ERCLM was performed by an EED 11--resistance type device. Length d1 was defined as the length of the root when measured to a value one degree less than the test value. Length d2 was defined as the length of the root inducted by the test value, which corresponded to the resistance of the periapical agar. RESULTS: In group 1 the average d1 length was 0.44 +/- 1.05 shorter than the anatomical foramen (AF), and in group 2, 1.11 +/- 0.43 mm longer than AF. In the control group the d1 length was on average--3.02 +/- 3.72 mm from the AF. The d1 values of all groups were not statistically significantly different from the anatomical length (AL). In all three experimental groups the d2 length was statistically significantly different from the AL (P < 0.05, t-test); group 1 d2 = AL + 6.32 +/- 1.38 mm; group 2 d2 = AL + 6.27 +/- 1.47; control group d2 = AL + 9.15 +/- 1.00 mm. CONCLUSIONS: The results of this study indicated that when the electroconductive medium in the canal had a different ion concentration than the periapex, and the canal orifice had a wide diameter (0.70 mm), the transitional concentration zone influenced the accuracy of measurement during ERCLM with a resistance type device. When ion concentrations inside and outside the canal were identical, in teeth with a wide foramen diameter (0.70 mm or more) the lack of a transitional ion concentration zone meant that the length of the root canal could not be determined by ERCLM.

Agar↗