Fused teeth were a phenomena of teeth anomalies in shape, which can affect the dental teeth both in primary and permanent dentition. Fused teeth do not only cause problems on crowding of dentition, abnormal occlusion and aesthetic, but also increase risks of dental caries, endodontics diseases, periapical diseases and periodontal diseases. Fusion of deciduous teeth may lead to abnormality of subsequent permanent teeth. Treatment of fused teeth may require multidisciplinary approach in endodontics, periodontics, oral and maxillofacial surgery, prosthodontics and orthodontics. The aim of the present article is to review the etiology, classification, clinical manifestations and treatment of fused teeth in order to provide dental clinicians with a reference of clinical management for fused teeth.
Humans ; Fused Teeth/therapy* ; Anodontia ; Tooth, Deciduous ; Dental Caries/therapy* ; Esthetics, Dental

OBJECTIVES: This study aimed to investigate the clinical characteristics of congenital deciduous teeth absence and its permanent teeth performance type by using panoramic radiographs. METHODS: A total of 15 749 panora-mic radiographs of 3-6-year-old children with deciduous dentition were collected from January 2020 to December 2021. The incidence of congenital deciduous teeth absence was observed, and the abnormality of permanent teeth was recor-ded. SPSS 24.0 software was used for statistical analysis. RESULTS: The incidence of congenital deciduous teeth absence was 2.54% (400/15 749), which was found in 217 girls and 183 boys, and the difference between the genders was statistically significant (P=0.003). The absence of one and two deciduous teeth accounted for 99.75% (399/400) of the subjects. In addition, 92.63% (490/529) of mandibular deciduous lateral incisor was congenitally absent, 44.80% (237/529) of deciduous teeth was absent in the left jaw, and less than 55.20% (292/529) was absent in the right; the difference between them was statistically significant (P=0.017). The absence of 96.41% (510/529) deciduous teeth in the mandibular was significantly more than that of 3.59% (19/529) in the maxillary, and the difference between was statistically significant (P=0.000). Furthermore, 68.00% (272/400) and 32.00% (128/400) of deciduous teeth were absent in unilateral and bilateral, respectively, and the difference was statistically significant (P=0.000). Four types of congenital deciduous teeth absence with permanent teeth were observed as follows: 1) 73.91% (391/529) of permanent teeth was absent; 2) 20.60% (109/529) of permanent teeth was not absent; 3) the number of fused permanent teeth accounted for 4.91% (26/529); 4) the number of supernumerary teeth was 0.57% (3/529). CONCLUSIONS Although the absence of congenital deciduous teeth is less common than that of permanent teeth, it affects deciduous and permanent teeth to some extent. Dentists should pay attention to trace and observe whether abnormalities are present in the permanent teeth and take timely measures to maintain children's oral health.
Male ; Female ; Humans ; Tooth, Deciduous ; Dentition, Permanent ; Tooth, Supernumerary/epidemiology* ; Anodontia/etiology* ; Tooth Abnormalities/complications* ; Fused Teeth/epidemiology*

OBJECTIVES: The upper molars generally have three roots; therefore, different combinations of fusion can occur, increasing the possibility of finding more complex root canal systems. The purpose of this study was to evaluate the prevalence and characterization of fused roots in first and second maxillary molars using cone-beam computed tomography (CBCT) in a Colombian population. MATERIALS AND METHODS: A total of 1274 teeth were evaluated, of which 534 were maxillary first molars and 740 were maxillary second molars. Axial sections were made at the cervical, middle, and apical levels to determine the prevalence of root fusion and the types of fusion. RESULTS: Overall, 43% of the molars (n = 551) presented some type of fused root. Root fusion was present in 23.4% of the maxillary first molars. The most frequent type of fused root was type 3 (distobuccal-palatal; DB-P) (58.9%). Root fusion was observed in 57.6% of the maxillary second molars, and the most prevalent type of fused root was type 6 (cone-shaped) (45.2%). Of the maxillary molars, 12.5% were classified as C-shaped. CONCLUSION: Within the limitations of this study, there was a high prevalence of fused roots in maxillary molars in the Colombian population, mainly in the maxillary second molars. In first molars, the most common type of fused root was type 3 (DB-P) and in second molars, the most common type was type 6 (cone-shaped). Additionally, molars with root fusion presented variation at different levels of the radicular portion, with implications for treatment quality.
Cone-Beam Computed Tomography ; Dental Pulp Cavity ; Fused Teeth ; Molar ; Prevalence ; Tooth

Fusion and gemination are developmental anomalies of teeth that may require endodontic treatment. Fusion may cause various clinical problems related to esthetics, tooth spacing, and other periodontal complications. Additional diagnostic tools are required for the diagnosis and the treatment planning of fused tooth. The present case report describes a case of unilateral fusion of a supernumerary root to an upper permanent central incisor with large periapical lesion in which a conservative approach was used without extraction of supernumerary tooth and obturated with mineral trioxide aggregate to reach a favorable outcome.
Cone-Beam Computed Tomography ; Diagnosis ; Esthetics ; Fused Teeth ; Incisor* ; Miners ; Tooth ; Tooth, Supernumerary

Fusion is an abnormality of tooth development defined as the union of two developing dental germs, resulting in a single large dental structure. This irregular tooth morphology is associated with a high predisposition to dental caries and periodontal diseases. As a result of recurring inflammatory periodontal processes, disorders such as periodontal pocket, pericoronitis, and paradental cysts may develop. A rare mandibular anatomic variation is the retromolar canal, which is very significant for surgical procedures. The fusion of a paramolar and mandibular third molar associated with a paradental cyst co-occurring with the presence of a retromolar canal is rare, and the aim of the present study is to describe the evaluation of this anatomical configuration using cone-beam computed tomography.
Anatomic Variation ; Cone-Beam Computed Tomography* ; Dental Caries ; Fused Teeth ; Molar, Third* ; Odontogenic Cysts ; Pericoronitis ; Periodontal Diseases ; Periodontal Pocket ; Tooth ; Tooth, Supernumerary

Tooth transposition is a disorder in which a permanent tooth develops and erupts in the normal position of another permanent tooth. Fusion and gemination are developmental disturbances presenting as the union of teeth. This article reports the nonsurgical retreatment of a very rare case of fused teeth with transposition. A patient was referred for endodontic treatment of her maxillary left first molar in the position of the first premolar, which was adjacent to it on the distobuccal side. Orthopantomography and periapical radiography showed two crowns sharing the same root, with a root canal treatment and an associated periapical lesion. Tooth fusion with transposition of a maxillary molar and a premolar was diagnosed. Nonsurgical endodontic retreatment was performed. At four yr follow-up, the tooth was asymptomatic and the radiolucency around the apical region had decreased, showing the success of our intervention. The diagnosis and treatment of fused teeth require special attention. The canal system should be carefully explored to obtain a full understanding of the anatomy, allowing it to be fully cleaned and obturated. Thermoplastic techniques were useful in obtaining hermetic obturation. A correct anatomical evaluation improves the set of treatment options under consideration, leading to a higher likelihood of esthetically and functionally successful treatment.
Bicuspid ; Crowns ; Dental Pulp Cavity ; Diagnosis ; Follow-Up Studies ; Fused Teeth* ; Humans ; Molar ; Radiography ; Radiography, Panoramic ; Retreatment* ; Tooth

OBJECTIVEThis study aims to investigate the prevalence and distribution of teeth number and morphology abnormalities in Chinese pediatric patients' permanent teeth at the mixed dentition stage by performing panoramic radiographs analysis.

METHODSA total of 4 347 panoramic radiographs of pediatric patients aged 5 years to 15 years who were admitted to the hospitals from September 2011 to September 2013 were reviewed. The presence of teeth number and morphology abnormalities were recorded as follows: congenitally absent teeth, supernumerary teeth, odontoma, microdontia, fused teeth, dilaceations, and cusp deformity. SPSS 16.0 software was used for statistical analysis.

RESULTSThe prevalence of teeth number and morphology abnormalities in pediatric patients' permanent teeth was 31.79% (1,382/4,347). The prevalence was higher in males. Significant difference between the genders was observed (P < 0.05). Tooth agenesis, the most frequent dental anomaly (15.00%, 652/4,347), was considerably common in females; supernumerary teeth (12.61%, 548/4,347) followed, which was significantly common in males. Both differences were statistically significant (P < 0.05). The levels of prevalence of both microdontia and dilacerations were 4.00% (174/4,347) and 2.16% (94/4,347). The prevalence of cusp deformity, odontoma, and fused teeth were relatively low at 0.74% (32/4,347), 0.51% (22/4,347), and 0.39% (17/4,347), respectively.

CONCLUSIONThe prevalence of teeth number and morphology abnormalities in children's permanent teeth at the mixed dentition stage is apparently high. Tooth agenesis and supernumerary teeth are the most frequent. Panoramic radiograph is an efficient method for the early diagnosis of teeth number and morphology abnormalities. This method can assist pediatric dentists to formulate treatment plans for children at the appropriate time.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Dentists ; Dentition, Mixed ; Dentition, Permanent ; Female ; Fused Teeth ; epidemiology ; Humans ; Male ; Odontoma ; epidemiology ; Patient Care Planning ; Prevalence ; Radiography, Panoramic ; Sex Factors ; Tooth Abnormalities ; diagnostic imaging ; epidemiology ; Tooth, Supernumerary ; diagnostic imaging ; epidemiology

In dentistry, the term 'fusion' is used to describe a developmental disorder of dental hard tissues. In the permanent dentition, fusion of a normal tooth and a supernumerary tooth usually involves the incisors or canines. However, a few cases of fusion involving premolars have also been reported to date. We present a rare case in which fusion of the maxillary left second premolar and a supernumerary tooth in a 13-year-old girl was diagnosed using cone beam computed tomography (CBCT, Alphard-3030, Asahi Roentgen Ind. Co., Ltd.). The tooth was bicuspidized after routine nonsurgical root canal treatment, and the separated teeth underwent appropriate restoration procedures. The second premolar and supernumerary tooth remained asymptomatic without any signs of inflammation after a follow-up period of 9 years. Identification of anatomical anomalies is important for treatment in cases involving fusion with supernumerary tooth, and therefore the microscopic examinations and CBCT are essential for the diagnosis. Fused teeth can be effectively managed by the comprehensive treatment which includes both endodontic and periodontal procedures.
Adolescent ; Bicuspid* ; Cone-Beam Computed Tomography ; Dental Pulp Cavity ; Dentistry ; Dentition, Permanent ; Diagnosis ; Female ; Follow-Up Studies ; Fused Teeth ; Humans ; Incisor ; Inflammation ; Tooth ; Tooth, Supernumerary*

Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.
Dental Pulp Cavity ; Fused Teeth ; Imaging, Three-Dimensional ; Incisor ; Multidetector Computed Tomography ; Tooth ; Tooth Abnormalities ; Tooth, Supernumerary

This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.
Adult ; Cone-Beam Computed Tomography ; methods ; Follow-Up Studies ; Fused Teeth ; diagnostic imaging ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Male ; Maxilla ; Molar ; abnormalities ; Molar, Third ; abnormalities ; Pulpitis ; diagnostic imaging ; Root Canal Therapy ; Tooth Root ; abnormalities ; Tooth, Supernumerary ; diagnostic imaging ; Tooth, Unerupted ; diagnostic imaging