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PubMedDate not supplied

[The periodontal reaction to root canal obturation with different filling materials].

Periodontal reactions and the apexification process in the teeth with open apex of the root in response to different filling materials and the relationship between these processes and the quality of filling of the root channels were studied in experiments. Zinc-eugenol paste, intradont, itradont-D and intradont with lysozyme were used to fill the root channels in puppies aged 6-7 months. Filling of the root channel up to the apex was found to be the optimal variant, preventing the development of necrosis and promoting periodontal tissue regeneration.

Animals↗

PubMed1998

Root resorptions in upper first premolars after application of continuous intrusive forces. Intra-individual study.

A scanning electron microscopy study of possible root resorptions and their localization after application of continuous forces of different magnitudes was conducted. Twelve upper first premolars, indicated for extraction, were previously intruded with constant forces. The teeth were divided into 3 groups: 1. non-moved control teeth, 2. continuous force application of 50 cN for 4 weeks, 3. continuous force application of 100 cN for 4 weeks. Specially designed NiTi-SE-stainless steel springs were utilized to exert the actual forces. After experimental tooth movement, the extracted teeth were dehydrated, metal-coated and examined by scanning electron microscopy. The intruded teeth showed resorptive areas consisting of lacunae (concavities) in the mineralized root surface. The teeth moved with 50 cN showed in the apical third several, in the medial third few, and in the cervical third no resorptive areas. In the case of the teeth moved with 100 cN, we observed resorptive areas in most of the apical third--including the apex contour-, several in the medial third, and none in the cervical third. In the control group no resorptions were observed. Thus, our results suggest that intrusion of human teeth with continuous forces induces root resorption, depending on the magnitude of force applied.

Adolescent↗

PubMed1992

A computed tomographic study of the distances between the maxillary sinus floor and the apices of the maxillary posterior teeth.

The mean distance between the apices of the maxillary posterior teeth and the floor of the maxillary sinus was measured from computed tomographic display data from 12 autopsy specimens and 38 human subjects. The distance from these apices to the adjacent lateral bony surfaces was also measured. The apex of the mesiobuccal root of the maxillary second molar was closest to the sinus floor (mean 1.97 mm) but farthest from the buccal bony surface (mean 4.45 mm). The apex of the buccal root of the maxillary first premolar was closest to the adjacent lateral bony surface (mean 1.63 mm) but farthest from the floor of the sinus (mean 7.05 mm).

Bicuspid↗

PubMed1981

Sexual dimorphism in the development, emergence, and agenesis of the mandibular third molar.

Bilateral agenesis was encountered in about 9% of the cases, with no significant sexual difference. The right and left mandibular third molars had the same pattern of development and emergence. The slight advance of girls over boys at the crown-completion stage was similar to previous observations on other mandibular teeth, particularly the second molar. The root development course of the third molar was faster in males than in females; this sexual dimorphism was much greater for retarded cases than for advanced cases. At the apex closure, the difference between median ages of males and females was 1.5 yr. Alveolar emergence tended to occur at a lower developmental stage in advanced cases compared with retarded cases.

Adolescent↗

PubMed2002

Short-term evaluation of intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin.

The purpose of this study was to evaluate intentional replantation of vertically fractured roots reconstructed with dentin-bonded resin. Twenty vertically fractured teeth were extracted intentionally and reconstructed with 4-META/MMA-TBB dentin-bonded resin. After reconstruction, the teeth were replanted into the original sockets. The replanted teeth were evaluated by clinical criteria and radiographic examination. The observation periods ranged between 4 and 45 months. Longevity was calculated by the Kaplan-Meier method, and factors that had significant influence on the longevity were analyzed with the Log rank test at a 95% level of confidence. From this short-term observation, 14 of 20 cases were functioned in the oral environment. Of these 14 cases, 6 could be considered truly successful and 8 cases needed further observation. The other six cases were total failures and were extracted. The longevity was calculated as 83.3% at 12 months and 36.3% at 24 months. Teeth with thin roots or with longitudinal fractures extending over 2/3 of the root from the cervical portion toward the apex showed significantly lower longevity. It was concluded that this method had the potential to preserve vertically fractured teeth.

Acrylic Resins↗

PubMed1997

[Veterinary dentistry (15). Apex resection in the horse].

Periapical disorders in horses can be treated by resection of the apex. The indications, contraindications, diagnosis, treatment and complications of the intervention are discussed. Four case reports of horses in which apicoectomy with retrograde endodontic treatment was performed are reviewed.

Animals↗

PubMed1990

[Changes with time in incomplete root and periodontal tissues of young dog teeth with torque loading applied].

We investigated, using labeling techniques (tetracycline, calcein) and routine histopathological methods (H. E. and Azan stainings), the histological changes with passage of time in incomplete root and the periodontium of young dog teeth with torque loading applied. The maxillary left first, second and third incisor teeth were used as anchorage teeth, and the maxillary right second incisor was loaded with either 3 degrees or 9 degrees torque. The orthodontic forces of these are 20-30 g and 80-90 g, respectively. Some temporal disturbances (such as mild, moderate, or severe bendings of labial and palatal apexes) were observed in certain regions of the apex of the incomplete root. However, with subsequent development of the root, the disturbances were repaired and pulp of the teeth was normally formed. Furthermore, although periodontium was also temporarily disturbed, it developed normally with the passage of time.

Alveolar Bone Loss↗

PubMed1984

[Rare case of hypertaurodontism].

The author observed a rare case of hypertaurodontism on a right lower molar n degree 2, with an apex like a lion's paw, a very low root trifurcation, but a normal ratio between the coronary and the radicular lengths. This anomaly may be due to an absence of any sub-coronary horizontal invagination in the Hertwig sheath, which would be hereditarily transmitted.

Adult↗

PubMed1993

Morphometric variables of developing primary mandibular second molars.

Morphometric variables of second primary molar crowns from birth to completion were examined and measured. An image analysing technique comprising a photographic camera, a monitor, a computer with appropriate software and a digital caliper was used. Strong correlations were found between the 'external' aspect of the crown (mesiobuccal cusp height, mesiodistal and buccolingual dimensions and perimeter), and between all the 'occlusal' measurements of the crown, i.e. all the intercusp distances. However, poor correlations were found between the external and internal measurements of the crown such as the mesiobuccal cusp height and mesiobuccal-mesiolingual cusp-tip distance. It was also found that the mesiobuccal cusp serves as the apex of two triangles, the one formed by mesial cusps, and one formed by the distal cusps. The cusps on the mesial portion of the crown (ML, DB) are on a similar radius from the MB cusp, and the cusps on the distal portion are on a similar radius from the MB cusp. The small sample is a limitation but the results suggest a separate and independent pattern and rate of development of the external and the occlusal morphological variables of the tooth crown. Further research is needed on larger samples.

Humans↗

PubMed2006

Mandibular fracture 2 weeks after third molar extraction.

This case report describes mandibular fracture after the surgical extraction of fully erupted lower third molar of a 53-year-old healthy male patient. The fracture occurred 15 days after the extraction while chewing. The fracture line extended from the apex of the mesiobuccal root socket to the inferior border of the mandible. Follow-up of the patient was agreed as the patient was not willing to carry on further treatment. Bony union was observed radiologically 3 months later.

Fracture Healing↗

PubMed2004

[An analysis of angles related to gingival cone and marginal gingiva in natural dentition].

PURPOSE: There are no reports on numerical investigation of suitable shapes of restoration. This study examines the relationship between gingival cone and marginal gingiva in natural dentition, and discusses the standard angles for giving a suitable shape at the gingival cone of restoration. METHODS: Twenty dental casts of healthy subjects with normal dentition were examined. The angles between gingival cone and marginal gingiva (CG angle), and the angles between gingival cone and the long axis of the tooth crown (CA angle) were measured. RESULTS: The mean CG angles of each site were measured between 96.7 degrees (palatal surface of the upper first molar) and 123.9 degrees (labial surface of the lower central incisor). Within the same kind of teeth, lower significant differences were observed among upper and lower, or buccal and lingual surfaces. The CG angles of anterior teeth were 9.5 to 19.2 degrees larger than those of posterior teeth. The CA angles of anterior teeth were negative, and the apex of gingival cone of anterior teeth was directed toward the incisal edge. Conversely, the CA angles of posterior teeth were positive, and the apex was directed toward the root apex. Significant negative correlation was found between CA angle and CG angle (p<0.001). CONCLUSIONS: These results suggested that the relationship between gingival cone and marginal gingiva is fairly constant throughout their angles, and that the cervical shape could affect the shape of marginal gingiva.

English Abstract↗

PubMed2006

Hypsodontia in Castor canadensis: an anatomical and histological study.

OBJECTIVES: The aim of this original study is to describe the dental morphology and anatomy of Castor canadensis and to compare results with existing data in the literature relating to this mammal. This will give us a better knowledge of its very distinctive dental system, representative of rodent typology. MATERIAL AND METHODS: The authors used an osteological sample that is rarely found in Europe. A series of horizontal histological sections of the labial and jugal dental organs were prepared at different coronal and radicular levels for study under the optic microscope. Coloration was applied for tissue differentiation. RESULTS: Observation of the histological sections reveals an enlargement of the space reserved for the pulp tissue which increases from the crown towards the widely open apex of the incisors. These characteristics are not found in the jugal teeth which, although they also have an open apex, present a different configuration. CONCLUSION: The dental organs of Rodents in general and Castorides in particular are subject to a constant eruptive force throughout their lifetime. This permanent dental growth occurs as the dental system undergoes intense abrasion, especially the incisors.

Animals↗

PubMed1993

Physiologic drift of the mandibular dentition following first premolar extractions.

A retrospective study of two groups of patients was conducted to evaluate the physiologic drift, or "driftodontics", of the mandibular teeth following the extraction of four first premolars. Group 1 included 32 patients who underwent early extraction in the mixed dentition stage at a mean age of 10.4 years; they were followed for approximately 2.5 years postextraction. Group 2 included 20 patients whose premolars were extracted after the permanent dentition had fully erupted. Their mean age at the time of extraction was 14.2 years, followed by a 0.8 year observation period. Except for the extractions, no other mandibular therapy was rendered. The results show no differences in rates of molar movements between groups. The molar apex moved mesially approximately 0.6 mm/yr; the molar cusp moved mesially approximately 1.2 mm/yr. In contrast, there were marked group differences in movements of the mandibular incisors and canines; rates of change were significantly greater in Group 2 than in Group 1. The canines drifted laterally and distally into the extraction sites while the incisors became more upright over basal bone and less crowded. Incisor irregularity decreased 1.3 mm/yr in Group 1 and 5.5 mm/yr in Group 2. The group differences in amounts of tooth movement were accounted for by changes in incisor crowding.

Adolescent↗

PubMed1976

Clinical evaluation of a root canal cement that contains paraformaldehyde.

The effectiveness of a Formalin-containing root canal cement in endodontic treatment is evaluated. A total of 76 teeth from 73 patients was used in a series of root canal treatments in which it was impossible to fill the canal to the apex; results of treatment were compared with the results in teeth with conventionally filled canals. The evaluation of the results shows Formalin-containing cements to have a useful place in endodontic therapy.

Adolescent↗

PubMed2004

Accuracy of supported root ratio estimation from projected length and area using digital radiographs.

BACKGROUND: The purpose of this study was to evaluate the accuracy of supported single-root surface ratio estimated from the length and projected area of the tooth, using digital dental radiographs. METHODS: Eight extracted, single-root teeth were three-dimensionally digitized using a contact technique for surface area measurement. The data were then processed using engineering application software and length, projection area, and true surface area of the root at a designated length were obtained. Based on these three measurements, the accuracy of the supported surface area ratio measurement at different lengths of the root was evaluated. RESULTS: The largest mean errors from linear and area estimation were 9.58% and -1.16%, respectively. The 95% confidence intervals were all positive, indicating that linear measurements overestimated supported ratio. T tests showed that linear estimations resulted in significant differences in all eight teeth and area estimations in five teeth. When analyzing the supported ratio of the alveolar bone receding from the cemento-enamel junction (CEJ) toward the apex of the root at each mm, linear estimation showed significant differences down to 8 mm, while area estimation showed significant differences only up to 2 mm. CONCLUSIONS: The results of this study indicate that a reliable estimate of the ratio of root surface area supported by alveolar bone cannot be determined from linear or area data. However, when the marginal bone destruction exceeds 2 mm from the CEJ, area estimation does not show a significant difference in the supported region. As demonstrated in this study, root surface ratio estimation function could be an advantage of digital dental x-ray systems in which projected root area is readily observed.

Alveolar Process↗

PubMed1990

Root canal system of the maxillary central incisor.

To better assess the efficacy of mechanical preparation of root canals, transparent specimens of 510 extracted maxillary central incisors were investigated for thickness and curvature of the root canal, condition of any accessory canals, and location of the apical foramen. Over 60% of the specimens showed accessory canals that are impossible to clean mechanically. Most lateral branches were small, 80% were the size of a #10 reamer or less, and only 3% were thicker than a #40 reamer. Apical foramina located away from the apex were observed in 45% of the teeth, although nearly 80% of all foramina were within approximately 0.5 mm of the apex, and 95% were within approximately 1.0 mm. Data on the thickness and curvature of the main canal showed that normally it is adequately prepared when reached with a #60 reamer to the apical constriction and supplemented by flare preparation.

Dental Pulp Cavity↗

PubMed1990

Apexification: review of the literature.

Five methods for the treatment of teeth with an incompletely formed apex (open apex) and a necrotic pulp are discussed. The methods discussed include the use of (1) a customized cone (blunt-end, rolled cone); (2) a short-fill technique; (3) periapical surgery (with or without a retrograde seal); (4) apexification (apical closure induction); and (5) one-visit apexification. The apexification techniques, which use various formulations of calcium hydroxide to induce closure, are stressed. Based on the review of the literature and clinical experience of the authors, it was concluded that successful treatment of an immature pulpless tooth can partly result from the antibacterial and calcification-inducing action of calcium hydroxide.

Calcium Hydroxide↗

PubMed2004

The radix entomolaris in mandibular first molars: an endodontic challenge.

AIM: To present cases of mandibular first molars with an additional distolingual root (radix entomolaris, RE) and to survey the literature on the incidence of this anatomical feature. SUMMARY: A major anatomical variant of the two-rooted mandibular first molar is a tooth with an additional distolingual and third root: the RE. The prevalence of these three-rooted mandibular first molars appears to be less than 3% in African populations, not to exceed 4.2% in Caucasians, to be less than 5% in Eurasian and Asian populations, and to be higher than 5% (even up to 40%) in populations with Mongolian traits. A total of 18 cases (12 root filled and six extracted mandibular first molars) with an RE were collected during the years 2000-2003 in patients of Caucasian origin. As far as the access was concerned, entering the root canal in the RE required a modification of the opening in a distolingual direction resulting in a trapezoidal opening cavity. None of the orifices was located midway between the mesial and distal root component. Based on the anatomy of the extracted samples and the bending of ISO 10 files after scouting of the root canal in the RE, three types of curvature were detected: (I) straight or no curvature (two cases); (II) coronal third curved and straight continuation to the apex (five cases); and (III) curvature in the coronal third and buccal curvature from the middle third or apical third of the root (11 cases). KEY LEARNING POINTS: Clinicians should be aware of this unusual root morphology in mandibular first molars in Caucasian people. Radiographs exposed at two different horizontal angles are needed to identify this additional root. The access cavity must be modified in a distolingual direction in order to visualize and treat the RE, this results in a trapezoidal access cavity.

Adult↗