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Objectives: Whether gemination or fusion, double teeth are rare worldwide, including Africa based on few published data. New cases from the continent are tallied, and anomalies potentially associated with double teeth are identified. These findings should interest a range of dental researchers. Methods: The presence of double teeth was recorded in 97 modern and premodern North and sub‐Saharan African samples (5631 inds.). They and coexistent anomalies are described relative to published examples. Prevalence was estimated as possible, using a Poisson model for 95% confidence intervals (CI). Results: Three maxillary double teeth were identified: a primary left lateral incisor in a Nubian child (1938–1756 BC), permanent left central incisor in an adult Egyptian (3650–3500 BC), and permanent right central incisor in a modern (19th century) adult from Guinea. Each co‐occurs, respectively, with a talon cusp, peg lateral incisor and, in the latter individual, second premolar crown variation with rotation, and third molar dens evaginatus. Double tooth prevalence is 0.048% (CI 0.001%–0.270%), with regional variation, in premodern, and 0.000% in modern North Africans. It is 0.000% for premodern and 0.048% for modern sub‐Saharan Africans (0.008%–1.714%). Conclusions: The double incisors are comparable to other global examples, indicative of common developmental processes during odontogenesis. Prevalence is lower than published modern rates, to suggest some exceptionality in Africans as reported earlier for other dental variants. Finally, though circumstantial, double teeth and accompanying anomalies may share an etiology. Continuing research overall, and in Africa specifically, will promote an improved understanding of double teeth formation and expression. [ABSTRACT FROM AUTHOR]

This article aims to understand the syntax of three causative constructions in Sason Arabic. It demonstrates that in geminate causatives and 'give' causatives, the causee is introduced in CauseeP, unlike the embedded agent in 'make' causatives, which embed a thematic VoiceP. Despite differing from Voice0$$ {}^0 $$ in several respects, Causee0$$ {}^0 $$, like Voice0$$ {}^0 $$, exhibits an active–passive‐like alternation, which provides independent evidence for an analysis of the passive that treats it as a subtype of the Voice head. The article further distinguishes between geminates and 'give' causatives on the basis of the (in)compatibility of the causee with an applied argument. In geminates, Causee0$$ {}^0 $$ and Appl0$$ {}^0 $$ are bundled, and the same argument bears two θ$$ \theta $$‐roles, whereas in other causative constructions, Causee0$$ {}^0 $$ and Appl0$$ {}^0 $$ remain separate, with each argument bearing a distinct θ$$ \theta $$‐role. [ABSTRACT FROM AUTHOR]

This report illustrates a rare case of a geminated maxillary right second molar tooth using CBCT in a 23-year-old man with severe pain. Nonsurgical endodontic treatment was performed, which gave rise to an asymptomatic tooth at the 12-month follow-up. [ABSTRACT FROM AUTHOR]

During the analysis of a skeletal assemblage from a medieval cemetery in Nubia (c. AD 500–1550), a young adult female with abnormally developed maxillary incisors was discovered. The possible causes of the two dental anomalies found in this individual and their archaeological context are discussed. The remains are from a medieval assemblage from the Fourth Cataract region of Nubia, which forms part of the Nubian collection curated at the British Museum. The left central incisor has a twinned crown with two root canals, and a supernumerary tooth is present on the right side between the central incisor and lateral incisors. Although two different dental anomalies are present, the bilateral expression suggests that the same biological mechanism could be responsible. [ABSTRACT FROM AUTHOR]

This paper reports a case of gemination in a maxillary lateral incisor with two root canals and crown-root dilaceration. A 16-year-old male patient was referred for endodontic treatment of the maxillary left lateral incisor and evaluation of esthetic and functional complaints in the anterior region. The patient reported trauma to the anterior primary teeth. There was no spontaneous pain, but the tooth responded positively to the vertical percussion test and negatively to the pulp vitality test. Clinical examination showed esthetic and functional alterations and normal periodontal tissues. CBCT imaging confirmed the suspicion of gemination and crown-root dilaceration and also revealed the presence of two root canals and periapical bone rarefaction. The root canals were instrumented with Reciproc R40 and 1% NaOCl irrigation and were filled by lateral condensation of gutta-percha and AH Plus sealer. The tooth was definitely restored with composite resin to recover esthetics. Continued follow-up over 6 months has shown absence of pain or clinical alterations as well as radiographic image suggestive of apical repair. [ABSTRACT FROM AUTHOR]

Supernumerary teeth may be defined as any teeth or tooth substance in excess of the usual configuration of 20 deciduous and 32 permanent teeth. Gemination is defined as an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. Geminated supernumerary premolar is a rarity and the possibility of multiple occurrences is even rarer. An exhaustive review of English literature and a PubMed search conducted using the terms “gemination’’ and “multiple geminated supernumerary” revealed no case of multiple geminated supernumerary premolars. We report a case of multiple geminated supernumerary premolars in a 23-year-old male. [ABSTRACT FROM AUTHOR]

Objective: To report a conservative treatment of a rare developmental anomaly.Case Report: A 73-year-old patient with previously initiated therapy and acute apical abscess of a maxillary right central incisor fused with the supernumerary tooth sought treatment. The conservative approach included nonsurgical root canal treatment and composite restoration.Conclusion: This case illustrates the importance of an individual approach when treating anomalous teeth. Priorities in pain and infection management to properly and functionally restore teeth should be unaffected by age. [ABSTRACT FROM AUTHOR]

Sachdeva GS, Malhotra D, Sachdeva LT, Sharma N, Negi A. Endodontic management of mandibular central incisor fused to a supernumerary tooth associated with a talon cusp: a case report. International Endodontic Journal, 45, 590-596, 2012. Abstract Aim To report the successful non-surgical endodontic management of a mandibular central incisor fused to a supernumerary tooth associated with a talon cusp. Summary Fusion and gemination are developmental anomalies of teeth that may require endodontic treatment. In this article, a case of successful endodontic management of a permanent mandibular right central incisor fused to its supernumerary counterpart associated with a talon cusp is reported. The incidence of fusion in mandibular anteriors is rare. A search of the literature failed to reveal any reports on the fusion of a permanent mandibular central incisor with its supernumerary counterpart associated with a talon cusp. Successful non-surgical endodontic management of a case is reported. Key learning points Fused and geminated teeth requiring endodontic treatment present diagnostic and technical challenges., An exact differentiation between fusion and gemination may not be critically important for treatment., The use of an operating microscope for detection of additional root canal orifices in complicated cases is recommended. [ABSTRACT FROM AUTHOR]

Oral Diseases (2011) , 221-231 The aim of this investigation was to study the epidemiology of the isolated soft tissue cleft lip (ICL) population and to evaluate the dental anomalies associated with permanent dentition. The study included 19 children aged 9-13 years presenting ICL selected from 657 cleft lip-affected patients treated during the last 10 years in two craniofacial centers. Only 17 patients could be included for dental anomaly evaluation: Hyperdontia, Hypodontia, Gemination, Talon tooth, Microdontia, and Macrodontia. These were compared with cleft lip and palate (CLP) and cleft lip and alveolus (CLA)-affected populations and with normal populations. The prevalence of ICL was 2.8%. All types of tooth abnormalities were found to be higher and mainly significant for the cleft side of ICL compared with the normal population. On the side opposite the cleft, the prevalence of dental anomalies reduced toward the normal individuals and was not significantly different. The significant differences found between CLP, CLA, and ICL-affected populations were mostly depicted by lateral incisors and second pre-molar hypodontia. Isolated cleft lip is a rare phenomenon among the spectrum of the cleft-affected population. The prevalence of the dental anomalies in ICL maintains the proportional trend according to clefting severity. [ABSTRACT FROM AUTHOR]

Weinstein T, Rosano G, Del Fabbro M, Taschieri S. Endodontic treatment of a geminated maxillary second molar using an endoscope as magnification device. International Endodontic Journal, 43, 443–450, 2010. Aim To describe endodontic treatment for a rare case of gemination. Summary A case of complex endodontic treatment in a geminated tooth is presented. With the assistance of microinstruments and magnification devices, a geminated maxillary second molar was successfully treated. In such a case, ultrasonic tips and the use of an endoscope were essential to detect the peculiar anatomy of the tooth involved. Key learning points • Knowledge of anomalies concerning fused teeth is essential. • Using an endoscope as a magnification device is useful during the inspection of pulp chambers. • Ultrasonic tips are safe and useful to detect canal orifices. [ABSTRACT FROM AUTHOR]

The phytohormone abscisic acid (ABA) regulates plant growth and development as well as stress tolerance. To gain more insights into ABA signalling, a population of chemical-inducible activation-tagged Arabidopsis mutants was screened on the basis of the ABA effect on the inhibition of seed germination. Two novel ABA supersensitive mutants ABA supersensitive during germination1 ( absg1) and absg2 were characterized as alleles of Dicer-like1 ( DCL1) and HEN1, respectively, as microRNA biogenesis genes, and accordingly, these two mutants were renamed dcl1-11 and hen1-16. The dcl1-11 mutant was an ABA hypersensitive mutant for seed germination and root growth. Reverse transcriptase polymerase chain reaction assays revealed that the expression of ABA- and stress-responsive genes was increased in dcl1-11, as compared with the wild type (WT). Furthermore, the germination assay showed that dcl1-11 was also more sensitive to salt and osmotic stress. The hen1-16 mutant also showed supersensitive to ABA during seed germination. Further analysis showed that, among the microRNA biogenesis genes, all the other mutants were not only enhanced in sensitivity to ABA, salt and osmotic stress, but also enhanced the expression of ABA-responsive genes. In addition to the mutants in the microRNA biogenesis, the interruption of the production of crucial components of other small RNA pathways such as dcl2, dcl3 and dcl4 also caused ABA supersensitive during germination. [ABSTRACT FROM AUTHOR]

Aim To present a case with various morphological irregularities requiring root canal treatment and to discuss the problems and options for orthograde root canal treatment. Root canal treatment of a double tooth presenting with an acute alveolar abscess is described. The anatomical variations of this tooth included double tooth, dental invagination, incomplete apical closure, three root canal systems and an internal lacuna . The tooth was treated nonsurgically with orthograde root canal treatment resulting in nearly complete radiographic apical repair after 4 years. Key learning points •Double teeth occur infrequently and may be distinguished from fusion, gemination, concrescence and dental twinning. •Several malformations may be present in a single tooth. •Orthograde root canal treatment may be an adequate treatment option even in teeth with a complex internal anatomy. [ABSTRACT FROM AUTHOR]

Aim Gemination or fusion is a rare occurrence in the mandibular posterior teeth. Endodontic treatment of these teeth needs special care and attention to the bizarre anatomy. The aim of this article is to describe the problems encountered and the strategy in treating such cases. Case report Two cases of complex endodontic treatment of fused/geminated teeth are presented. The first is an 11-year-old girl with an anomalous 'double' first mandibular molar and premolar diagnosed as having necrotic pulp with chronic apical abscess of endodontic origin; the second is a 16-year-old boy with 'double' second and supernumerary mandibular molars, who was diagnosed with irreversible pulpitis. Both cases were treated successfully in multiple appointments. The common features and treatment modalities are discussed. Key learning points • Failure to diagnose fused/geminated teeth leads to misdiagnosis and a treatment plan that could cause permanent damage and tooth loss. • Generally, there is communication between root canal systems of fused/geminated teeth which should be treated as one entity. • Use of magnification is an important aid during treatment. [ABSTRACT FROM AUTHOR]

Aim A geminated maxillary incisor required complex multidisciplinary treatment to preserve health and restore aesthetics. This report describes the coordination of coronal division, root extraction, bone grafting, endodontic treatment and orthodontics in achieving treatment goals. It is the intention of this report to show how a difficult case could be managed by properly coordinated multidisciplinary care. Summary Pulp testing of the geminated central right maxillary incisor gave a normal response. Radiographic investigation indicated a connection of the pulp chambers. Both the mesial and distal root were filled with gutta-percha. The connection between the two root canals was sealed with a flowable dentine-bonded resin. After dividing the crown with a diamond bur, the mesial part of the tooth was removed and the extraction socket was filled with beta-tricalcium phosphate ceramic (Cerasorb[SUPTM]). Radiographs taken immediately after surgery and after 6 months showed no periodontal or periapical lesions. No signs of external resorption were identified. The diastema between the central incisors was closed by orthodontic treatment. Key learning points • Geminated teeth may present aesthetic and functional problems which require multi-disciplinary care. • Careful clinical and radiographic examination is essential to decide on the fate of the coronal and root halves involved. • A proper coordination between endodontic and surgical treatment may result in maintaining one tooth half, even if a midroot connection between the pulp chambers becomes evident. • Orthograde endodontic treatment, hemisection and orthodontics may solve the aesthetic problem of a geminated tooth. [ABSTRACT FROM AUTHOR]

Abstract Aim To describe a rare case of gemination involving a mandibular first premolar. Summary The complex morphology of geminated teeth renders their endodontic and periodontal management difficult. Root canal and periodontal treatments were performed on a geminated mandibular first premolar with three canals. Clinical examination showed two separated crowns with united roots. Radiographically, two distinct pulp chambers with two joined and a third independent canal were seen. Conventional root canal treatment resulted in complete healing of the apical lesion. However, the occurrence of a vertical fracture led to the extraction of the mesial segment. At the follow-up visit, the distal segment was clinically healthy and continued to satisfy functional demands. Key learning points •Failure to diagnose the initial crack along a gemination groove resulted in further propagation and finally complete vertical fracture. •Owing to the abnormal morphology of the crown and the complexity of the root canal system in geminated teeth, treatment protocols require special attention. •For asymptomatic cases without aesthetic or orthodontic problems and without associated pathosis, routine review and careful maintenance are required. [ABSTRACT FROM AUTHOR]

Changes in abscisic acid content during maturation of hybrid larch somatic embryos (Larix × leptoeuropaea), were followed using an enzyme immunoassay (ELISA). In the presence of 60 μM cis-trans (±)-ABA in the maturation medium, the cis-trans (±)-ABA level of the somatic embryos in planta increased during the maturation phase to reach a maximum value at week 5. Concomitantly, an extension of the period of maturation from 3 to 4 and 5 weeks resulted in a significant decrease in both germination and plantlet frequencies. As a consequence, we assume that it was the level of ABA in planta that was responsible for the inhibition. ABA acted in both a stimulatory and an inhibitory manner. If ABA promoted the obtention of high quality somatic embryos in large numbers, it also had a deleterious effect on the subsequent development, i.e. germination and plantlet recovery. The results stressed the importance of both the procedure and duration of maturation. [ABSTRACT FROM AUTHOR]

Fusion and gemination of permanent teeth are deveopmental anomalies of the dental hard tissues which may require endodontic and surgical treatment for functional, orthodontic or aesthetic reasons. Following a review of the dental literature on tooth fusion an gemination, a case of fusion of a maxillary central incisor and a supernumerary tooth and its endodontic and surgical treatment is presented. [ABSTRACT FROM AUTHOR]

Gemination and twinning are two rarely encountered developmental abnormalities. Although the precise etiology remains unknown, genetic predisposition is often suggested in the process. In the present study a maxillary incisor with three crowns of conical shape and three roots which were presumed to be the gemination of the tooth due to trauma, is reported. [ABSTRACT FROM AUTHOR]

In this article we report a case of a mandibular lateral incisor in which 3 separate root canals were located. Clinical and radiographic examinations suggested that fusion had occurred between the mandibular incisor and a supernumerary tooth. The endodontic management of the tooth is described, and repair of an apical periodontitis had occurred after 9 months. [ABSTRACT FROM AUTHOR]

Abstract Nahmias Y, Rampado ME. Root-canal treatment of a trifid crown premolar. International Endodontic Journal , 35 , 390–394, 2002. Aim To describe successful root-canal treatment of a permanent maxillary first premolar with unusual anatomy. Summary A diagnosis of irreversible pulpitis of a geminated first premolar was made. Clinical and radiographic examination revealed a tooth with a trifid crown that joined to give the appearance of a single root at the cementoenamel junction. Root-canal treatment involved three separate access openings and treating four canals, three of which joined to exit through a common foramen. Key learning points • Symptomatic teeth with morphological aberrations can be saved by root-canal treatment. • Careful clinical and radiographic evaluation are essential, as treatment must be modified to address the unusual complexities of the root-canal system(s). [ABSTRACT FROM AUTHOR]