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PubMed2002

Root surface area of the mandibular cuspid and bicuspids.

BACKGROUND: The purpose of this study was to determine the total root surface area of extracted teeth by computerized image analysis and the amount of remaining attachment area assuming various amounts of bone loss due to periodontal disease. METHODS: One hundred fifty extracted mandibular teeth were evaluated, and measured from cusp tip to the cemento-enamel junction (CEJ), CEJ to root apex, and cusp tip to root apex. The fulcrum point of the tooth was also measured, along with the total root surface area of attachment and total surface area of attachment remaining following simulation of attachment loss in 2 mm increments. Measurements were made on 80 teeth on one proximal surface and either the buccal or lingual surface and multiplied by a factor of 2. Measurements on 70 teeth were made on all 4 root surfaces to predict the accuracy of measuring only 2 surfaces to determine root surface area. Images of the tooth surfaces were obtained by video camera and converted to computer image with measurement of the surface areas. RESULTS: The total root surface area for the mandibular cuspids and first and second bicuspids was 275.88 mm2, 251.45 mm2, and 271.81 mm2, respectively. The 2-sided and 4-sided measurements for the mandibular first bicuspid were 252.55 mm2 and 247.02 mm2, respectively (P>0.05). CONCLUSIONS: This study found the total root surface area to be greater than that in most previous studies. Increasing attachment loss is related to decreasing root surface area; however, this relationship is not directly proportional. No statistical difference was found between measuring 4 surfaces versus only 2 surfaces.

Alveolar Bone Loss↗
PubMed1990

Differential diagnosis between cyst and tumor. Dentigerous cyst and ameloblastoma containing teeth.

A study was conducted on 21 cases of ameloblastoma (a type of tumor containing an embedded tooth) and 87 cases of dentigerous cyst. The former cases were selected from among those which had been diagnosed histopathologically. Using radiographs of these lesions, the following parameters were measured: 1) the distance between the cement-enamel junction of the embedded tooth and its attachment to the cystic wall; 2) the area of the radiolucent image (similar to the area with a cystic appearance). From measurements of the former parameter, it appeared that the embedded tooth extends more toward the root apex in ameloblastoma than in dentigerous cyst, whereas the latter parameter indicated that the radiolucent area varies in size slightly in ameloblastoma, but tends to be smaller in dentigerous cyst. Moreover, with regard to clustering between ameloblastoma and dentigerous cyst, no definite tendency was detected on distance, whereas only ameloblastoma without dentigerous cyst was seen above 20 cm2 of area.

Adolescent↗
PubMed2004

[Postobturation pain associated with endodontic treatment].

Postobturation pain of different origin after endodontic treatment was studied in 100 patients after treatment of 151 teeth with filling of 264 channels. 34.4% patients complained of pain. The incidence and intensity of pain were scored. Postobturation pain clearly depended on the number of treatment sessions, number of channels filled in one tooth, and excessive filling "beyond the apex". The method of "crown down" preparation using completely rotating profile instruments and GT rotary files proved to be most effective as regards prevention of postoperative pain.

Adult↗
PubMed1996

Early tooth movement pattern after application of a controlled continuous orthodontic force. A human experimental model.

This clinical study was designed to investigate early orthodontic movement of human premolars subjected to a controlled, continuous, horizontally directed force. The maxillary right, first or second premolar in 56 children, 18 boys and 38 girls (mean age 13.8 years), was moved buccally with a fixed orthodontic appliance with a frontal bite-block disengaging the occlusion. The contralateral premolar served as control. A weekly controlled and reactivated force of 50 cN (approximately 50 gm) was applied. The force declined on average about 24% per week. The patient material was subgrouped to comprise eight patients in each of seven groups, for which the experimental periods varied from 1 to 7 weeks. Tooth displacement was studied on dental casts, with a coordinate measuring machine (Validator 100, TESA SA, Renens, Switzerland), which made it possible to measure the displacement in three dimensions. The movement pattern of the test teeth was found to be a combination of horizontal and vertical displacements, including tipping. The horizontal movement of the tooth crown was on average 0.8 mm during the first week and 3.7 mm after 7 weeks. The vertical movements were intrusive in 45% and extrusive in 55% of the teeth. In some tipping movements, the crown was "intruded" at the same time as the apex was "extruded." The individual variations in tooth displacements were considerable. The clinical experimental model used permits detailed study of orthodontic tooth movement under controlled force conditions, as well as detailed histologic analysis of related root resorption.

Adolescent↗
PubMed2004

In vitro evaluation of the accuracy of three electronic apex locators.

The accuracy of three electronic apex locators (EALs) (Justy II, Root ZX, and Neosono Ultima EZ) is evaluated, together with the concordance of the measurements obtained by two different operators. Twenty single-root human teeth were used, sectioning the crown to gain access to the root canal. A first operator (A) determined the reference (or control) length (corresponding to the actual length) for each tooth, after which all teeth were measured individually and independently by the other two operators (B and C). The results obtained with each EAL and by each operator were in turn compared with the corresponding control length. The statistical analysis of the results showed EAL reliability in detecting the apex to vary from 80% to 85% and 85% to 90% (depending on the operator) for the Justy II and Neosono systems, respectively, whereas reliability was found to be 85% for the Root ZX device. These results, combined with a high interobserver concordance, suggest electronic root canal measurement to be an objective and acceptably reproducible technique.

Chi-Square Distribution↗
PubMedDate not supplied

Replantation of avulsed primary anterior teeth: treatment and limitations.

In addition to the successful replantation of avulsed permanent teeth, the replantation of primary anterior teeth may also be indicated. The decision is based on age and stage of tooth development, development of dentition, storage of the avulsed tooth and the way it is transported to the treatment site, the appropriate in vitro treatment of the tooth before reinsertion, and the willingness of the child to cooperate. A method involving retrograde filling of the primary tooth root with calcium hydroxide after resecting the root apex has proved successful. Other commercially available root filling materials and pins are not indicated. Calcium hydroxide allows the tooth to heal in place without reaction and prevents the development of apical periodontitis. As regards any surgical intervention, the attending dentist in this case has to weigh the benefits against the risks.

Age Factors↗
PubMed2026

Vertical distribution of accessory canals in different tooth types: A systematic review and meta-analysis.

OBJECTIVE: To systematically analyze the vertical distribution of accessory canals and propose potential root-end resection levels in different tooth types. DATA: Proportional distribution of accessory canals (PD-AC) in 1 mm intervals, cumulative proportions within 2 mm and 3 mm (CP-AC0-2 and CP-AC0-3), mean distance from accessory foramen to root apex or main foramen (MD-AF), and prevalence of accessory canals in 2D cross-sections (PR-AC-2D). SOURCES: A systematic search of electronic databases was conducted through December 25, 2025. The review was registered in PROSPERO (CRD420251107855). STUDY SELECTION: Two reviewers independently performed study selection, data extraction, and risk of bias assessment using the AQUA tool. Nineteen studies were included for qualitative synthesis, of which eleven provided sufficient data for meta-analysis. A random-effects model was used, and subgroup analyses were stratified by tooth type, accessory canal type, and country. Within 0-1 mm, 1-2 mm, 2-3 mm, and 3-4 mm from the apex, 41.5%, 34.3%, 9.9%, and 4.4% of accessory canals were located, respectively. Molars had significantly higher proportions than anterior teeth both within 2 mm (90.0% vs. 72.4%) and 3 mm (96.9% vs. 87.5%). Of apical ramifications, 86.4% were within 2 mm. The pooled MD-AF was 1.472 mm. PR-AC-2D decreased from 29.3% at 1 mm to 1.3% at 5 mm. All studies presented moderate to high risk of bias. CONCLUSIONS: A 2 mm root-end resection level may be sufficient for molars, whereas anterior teeth may require a higher level. Further randomized controlled trials are needed. CLINICAL SIGNIFICANCE: A 2 mm resection may adequately expose or remove most accessory canals in molars, potentially preserving more root length while maintaining treatment efficacy. In anterior teeth, a traditional 3 mm resection remains advisable until further evidence becomes available.

Humans↗
PubMed1993

In vivo measurement accuracy in vital and necrotic canals with the Endex apex locator.

Currently apex locators are being used to determine working length. This study was undertaken to see what is actually being measured and if the pulp status, i.e. vital or necrotic, makes a difference in the determination. In this in vivo study, 33 teeth, both vital and necrotic, were measured by the Endex apex locator and then radiographed. After the length determination, the file was cemented to place, the tooth extracted, and then shaved back until the file and the apex were exposed. The position of the file was measured in relation to the apical foramen. Results indicate that all measurements were within a narrow range (-0.86 mm to 0.50 mm). There was no statistical difference in measurements between vital and necrotic canals.

Dental Pulp Cavity↗
PubMed2006

Microstructure of pharyngeal tooth enameloid in the parrotfish Scarus rivulatus (Pisces: Scaridae).

The microstructure of parrotfish pharyngeal teeth was examined using scanning electron microscopy to infer possible mechanical properties of the dentition with respect to their function. Parrotfish tooth enameloid is formed from fluorapatite crystals grouped into bundles. In the upper and lower pharyngeal jaw, the majority of the crystal bundles are orientated either perpendicularly or vertically to the enameloid surface. The only exception is in the trailing apical enameloid in which the majority of bundles are orientated perpendicularly or horizontally to the trailing surface. A distinct transition occurs through the middle of the apex between the leading and trailing enameloid in teeth of the lower pharyngeal jaw. This transition appears less distinct in the teeth of the upper pharyngeal jaw. Enameloid microstructure indicates that shear forces predominate at the apex of the teeth. In the remainder of the enameloid, the microstructure indicates that wear is predominant, and the shear forces are of less importance.

Animals↗
PubMedDate not supplied

Soft tissue healing around implants placed immediately after tooth extraction without incision: a clinical report.

PURPOSE: The purposes of the present study were to evaluate implants placed immediately after tooth extraction without incision or primary flap closure and to observe the peri-implant soft tissue healing. MATERIALS AND METHODS: Fifteen patients (9 men and 6 women) aged 31 to 54 years were included in this study. Each patient had a tooth that required extraction, and each had at least 4 mm of bone beyond the root apex. Teeth with multiple roots were excluded from this study. After tooth extraction, the implants were immediately placed without incision or flap elevation. Implant sites showing bone fenestrations, bone dehiscences, or peri-implant bone defects exceeding 2 mm were excluded from this study. In these cases, a standard guided bone regeneration procedure with a surgical flap elevation was used. The second-stage surgical procedure was performed 6 months after the first procedure. The following clinical parameters were evaluated at the time of implant placement and at second-stage surgery: levels of mesial and distal papillae, width of keratinized mucosa, position of mucogingival junction relating to the surrounding tissues, and peri-implant radiolucency and marginal bone loss, which were evaluated radiographically. RESULTS: The postsurgical healing period was uneventful for all patients. Soft tissue closure over the implant sites was achieved in 1 to 3 weeks after surgery at all sites. At second-stage surgery, no peri-implant bone defects were observed or detected by probing around all the experimental implants. The soft tissue anatomy was considered clinically acceptable in all patients. DISCUSSION AND CONCLUSION: Successful osseointegration and complete bone healing were observed for all patients. The soft tissue healing and morphology were satisfactory; additional mucogingival surgery was not required before definitive prosthetic rehabilitation.

Adult↗
PubMed1999

Radiographic evaluation of alveolar bone height in HIV-positive patients.

BACKGROUND: This prospective case-control study was performed to assess alveolar bone height in HIV-positive and HIV-negative patients. METHODS: Twenty-three HIV-positive patients, 16 men and 7 women, aged 24 to 40 years (mean age: 33 years), consecutively referred to the Dental Clinic, University of Ferrara, for clinical and radiographic assessment of oral conditions, were included in the study (test group). All patients had undergone laboratory evaluation to assess HIV-infection status and were classified according to CDC diagnostic criteria. Nineteen patients were intravenous drug abusers. Thirty-four HIV-negative subjects were matched for demographic characteristics and smoking status as a control group. Radiographic evaluation was based on panoramic radiography and bone measurements were limited to premolars and molars. Alveolar bone height was measured mesially and distally to each tooth and determined as the distance from the apex of the root to a point where the lamina dura became continuous with the compact bone of the interdental septum. Alveolar bone height was recorded as well as the ratio between alveolar bone height and tooth length. RESULTS: The results indicated a tendency for a difference in alveolar bone height between groups, lower in the test group compared to controls. However, this difference only reached statistical significance on a tooth-specific basis. CONCLUSIONS: In conclusion, the results show a greater trend for alveolar bone loss of posterior teeth in HIV-positive patients compared to HIV-negative patients.

Adult↗
PubMed2005

Detection of lingual root resorptions in the intraoral radiographs. An experimental study.

An experimental study was undertaken in an attempt 1) to describe the possibilities to detect lingual root resorptions of upper incisors in intraoral radiographs and 2) to determine the amount of reduction that is necessary in order to detect resorptions in the radiograph. The upper right central incisor was extracted from a dry skull. In a standardized way, the root was repeatedly reduced by grinding on the lingual side at an angle of 16 degrees measured from apex to the long axis of the tooth. After each reduction the tooth was replaced in the dry skull and radiographed in a standardized manner. The radiographs were placed in two different charts and at random within each chart. On two different occasions three groups of observers, 5 orthodontists, 5 pedodontists and 5 radiologists were asked to register any detected "root resorptions" on the right first and second incisors. The first chart included radiographs with a reduction of 0-3 mm and the second chart 0-6 mm. The orthodontists and pedodontists were not very consistent in their observations and false positive registrations were very frequent. The radiologists were more accurate in their observations and detected resorptions when the reduction incorporated the apex of the root at a 3 mm level. Thus, intraoral radiographs seems to be a very blunt instrument for detecting lingual root resorptions.

Humans↗
PubMed2004

[Effects of post material on stress distribution in dentine].

OBJECTIVE: To investigate stress distribution of different material restored post-cores in dentine and provide a theoretical guidance for clinical use. METHODS: A three-dimensional finite element model of maxillary central incisor restored with post-core and PFM crown was constructed by SCT scan technology. Based on this model, stress distribution in dentine was analyzed before and after post-core restorations with 6 different materials, including cast Ni-Cr alloy, cast titanium alloy, cast gold alloy, glass fiber reinforced composite, polythene fiber reinforced composite, and common composite resin. RESULTS: When the tooth was restored with cast Ni-Cr alloy post and PFM crown, the maximum tensile stress and Von Mises stress in dentin at post apex increased 152% and 162% respectively, compared with a tooth restored only with PFM crown. If polythene fiber reinforced composite was used as post material, the stress distribution did not significantly change. When the other materials were used for the post, the stress distribution changed greatly. The elastic modulus of post-core materials affected the stress distribution pattern in dentine. CONCLUSION: The materials with elastic modulus similar to that of dentin, such as polythene fiber reinforced composite, may be suitable for post restoration.

Chromium Alloys↗
PubMed1991

Radiographic and electronic diagnostic systems.

Radiography forms the basis for determining the length of tooth in endodontic therapy. Radiographs can be manipulated by digital image processing, which can improve their diagnostic quality as well as enable the images to be stored electronically. Electronic apex locators, when used in conjunction with radiographs and electronic imaging systems, become useful adjuncts in endodontic treatment. They provide the clinician with the ability to accurately determine the length of tooth, thus making apex locators an important component in endodontic therapy.

Dental Pulp Cavity↗
PubMed1992

Apicectomy: localization and isolation of the radicular apex.

Apicectomy is a surgical root approach achieved to the preservation of the tooth any time this is possible. To effect a good procedure of primary importance is an anatomic knowledge because all depends on the right localization of the root apex. A radiography must be done before starting any surgical approach in order to have more acquaintance as possible about the exact location, form and correlations with the nearby anatomic parts. The second step after location of apex is its isolation by different procedures. Afterwards the retrograde filling in amalgam is effected. The use of this kind of filling makes the isolation of the surgical field extremely important in order to have a full success, if the isolation is not perfect then all the procedure will not be valid.

Apicoectomy↗
PubMed2004

Resolution of persistent periapical infection by endodontic surgery.

AIM: To examine the surfaces of a root tip removed during surgical endodontic treatment for the presence of microorganisms. SUMMARY: The present clinical case illustrates an endodontic retreatment of a maxillary premolar tooth with a fistula and periapical reaction. The case was under treatment for 1 year, during which an intracanal medicament was replaced several times. As the lesion did not decrease and exudate was persistent through the fistula and root canal, root end resection with root end filling was performed. Microbiological samples were collected from the fistula, where Propionibacterium acnes, a species associated with endodontic failures, was detected by appropriate anaerobic technique. The resected root apex was observed by scanning electron microscopy (SEM), which revealed cocci and fungal forms surrounding one of the foramina. After 12 months, the periapical lesion had reduced.

Adult↗
PubMed1989

A three-dimensional evaluation of the effects of functional occlusal forces on the morphology of dental and periodontal tissues of the rat incisor.

We examined the effect of function on tooth and periodontal ligament (PDL) morphology in 40 lower incisors of adult female rats. Ten teeth were exposed to occlusal hyperfunction for three months, ten to hypofunction for three weeks, ten to hypofunction for three months, while ten teeth in normal occlusion served as control. Transverse ground sections were cut at various levels perpendicular to the tooth long axis, and their distances from the apex were calculated. The outlines of the tissues were traced and fed into a computer. We plotted the measurements according to their location and fitted them by second-order polynomials. We calculated tissue volume for the proximal 18 mm of bone-embedded tooth. Hyperfunction affected tooth shape, in that it became more rounded. The volumes of the dental tissues remained unchanged, while width and volume of the cementum-bordering PDL increased. Hypofunction did not alter tooth shape, but influenced its size: After three weeks, tooth circumference decreased, and after three months, it expanded. Dentin width was reduced, with concomitant increase of pulp size. The amount of enamel diminished initially, but after three months returned to normal values. The PDL bordering enamel expanded proportionally to the duration of hypofunction. The changes in socket size reflected the total dimensional variations in the tooth and its PDL. The results demonstrate that the shape and size of growing teeth and their periodontium are influenced by functional occlusal forces.

Alveolar Process↗