Fourth Molar Research Articles

Supernumerary fourth molar and dental pathologies in a Chalcolithic individual from the El Mirador Cave site (Sierra de Atapuerca, Burgos, Spain)

We present a middle-aged Chalcolithic male with a supernumerary distomolar in the mandible. The prevalence of supernumerary teeth in present-day populations is low, ranging from 0.1% to 3.4%; most supernumerary teeth are documented in the anterior and molar regions of the maxilla in present populations. However, the prevalence of supernumerary molars in past populations is still unknown. Moreover, a complete pathological study has been done of this individual.Maxilla, mandible and teeth have been analyzed searching for dental pathologies. A cone-beam computed tomography (CBCT) analysis of mandibular and maxillary fragments was performed to check the evidence of hyperdontia. Dental wear and maxillary alveolar bone have been analyzed with environmental scanning electronmicroscope (ESEM) to improve the diagnosis of an abscess and evidence of tooth picking.This individual shows a left distomolar in the mandible without any evidence of other supernumerary teeth. The fourth molar is not associated with any congenital disease. However, this individual suffered severe dental wear and a variety of oral pathologies such as, dental decay, abscesses, pulpitis, periodontal disease, toothpicking marks in an upper molar, arthritis of the temporomandibular joint and malocclusion associated with high masticatory loads. To our knowledge, this individual from El Mirador Cave (Sierra de Atapuerca, Spain) shows the most ancient case of a fourth molar documented. The poor oral health of this individual corresponds to the general dental health of Chalcolithic populations.

Taurodontism, variations in tooth number, and misshapened crowns in Wnt10a null mice and human kindreds.

WNT10A is a signaling molecule involved in tooth development, and WNT10A defects are associated with tooth agenesis. We characterized Wnt10a null mice generated by the knockout mouse project (KOMP) and six families with WNT10A mutations, including a novel p.Arg104Cys defect, in the absence of EDA,EDAR, or EDARADD variations. Wnt10a null mice exhibited supernumerary mandibular fourth molars, and smaller molars with abnormal cusp patterning and root taurodontism. Wnt10a−/− incisors showed distinctive apical–lingual wedge-shaped defects. These findings spurred us to closely examine the dental phenotypes of our WNT10A families. WNT10A heterozygotes exhibited molar root taurodontism and mild tooth agenesis (with incomplete penetrance) in their permanent dentitions. Individuals with two defective WNT10A alleles showed severe tooth agenesis and had fewer cusps on their molars. The misshapened molar crowns and roots were consistent with the Wnt10a null phenotype and were not previously associated with WNT10A defects. The missing teeth contrasted with the presence of supplemental teeth in the Wnt10a null mice and demonstrated mammalian species differences in the roles of Wnt signaling in early tooth development. We conclude that molar crown and root dysmorphologies are caused by WNT10A defects and that the severity of the tooth agenesis correlates with the number of defective WNT10A alleles.

A rare case of retained fourth molar teeth in maxilla and mandible. Case report

Abstract The study presents a case of the rarely occurring totally retained fourth molar teeth simultaneously in maxilla and mandible. The appearance of supernumerary teeth is a relatively uncommon dental anomaly and it is rare for patients to have impacted fourth molars in two quadrant. The aim of this work is to describe the presence of unilateral (right) fourth molars in the maxilla and the mandible in a young female patient aged 24 years. Orthopantomogram revealed impacted lower third molars but also unerupted unilateral (right) upper and lower fourth molars. Before orthodontic treatment, the patient was subsequently admitted for removal of third and fourth impacted upper and lower molars under local anesthesia.

Mandibular bilateral fourth molars - a rare and interesting occurrence.

A 24-year-old healthy male visited our private clinic in Bangalore with chief complaint of pain and discomfort in lower right back teeth region since 4-5 days. On intraoral examination, soft tissues which covered 3/4th of occlusal (distocclusal) surfaces of 48 appeared to be moderately inflamed and the other entire oral tissues appeared to be normal. An IOPA radiograph in relation to 47, 48 was taken and a diagnosis of a partially impacted (soft tissue impaction) third molar with pericoronitis was given. The patient was advised surgical removal of third molar, for which he gave his consent. Third molar extraction was planned and it was successfully done under local anaesthesia, based on IOPA radiograph, but intra operatively, distal to third molar, a globular mass of enamel like glossy appearance was observed, which prompted us to investigate further by orthopantomography (OPG). OPG revealed impacted, bilateral, mandibular fourth molars [Table/Fig-1]. Considering the possible complications, both the distomolars were planned to be surgically removed after obtaining the patient’s consent. The distomolars were of supplemental type, which resembled third molars. After one week, post-operative oral examination revealed uneventful healing. Anna KS called them as “ghost tooth” which had evolved from behind third molars [1]. [Table/Fig-1]: OPG revealing impacted mandibular bilateral 4th molars The prevalence of Supernumerary Teeth (ST) for deciduous teeth varies between 0.3% to 0.8%, whereas for permanent teeth, it ranges between 2 and 3.8%, depending upon the literature source/population [2]. Multiple opinions regarding their aetiology exist. Most authors point to phylogenetic factors (atavism) and state that they result from continued hyper activity of dental lamina, whereas some authors opine that they arise from dichotomy of tooth germ [3]. A careful check for a family history of ST could point to the presence of a genetically determined syndrome. Whether odontomas come under the category of ST, is still a controversy, in most of the literature sources. They are most of the times designated as evolutive odontogenic tumours. Hence, studies involving ST, exclude odontomas, though morphologically they resemble ST. If multiple ST are found, anamnesis can be done to rule out congenital abnormalities/syndromes which may have many other significant features.

Unilateral maxillary distomolar: A case report and review of the literature

Supernumerary teeth are defined as those in addition to the normal series of deciduous or permanent dentition. Supernumerary teeth is more prevalent among males and in the permanent dentition. The exact etiology of supernumerary teeth is unknown, they may occur anywhere in the oral cavity. They may appear as a single tooth or multiple teeth, unilaterally or bilaterally, erupted or impacted, maxilla or both jaws, it may be syndrome associated or it may not, The most common supernumerary teeth is mesiodense, Supernumerary teeth may be classified according to chronology, location (topography), morphology and orientation. A 37year old otherwise healthy woman patient was referred to the department of Oral Medicine of shorish dental teaching hospital, Sulaimani, for routine general dental check up, intraoral examination showed calculus on the lingual surface of the lower anterior teeth, the patient was sent for pantomography, pantomography revealed unilaterally impacted maxillary distomolar by chance, distomolar displayed normal tooth morphology with no any associated pathology. supernumerary impacted fourth molar is a rare phenomenon; the exact etiology is unknown, some of them produce complications, mostly they are chance radiographic finding, the treatment is controversial, and the decision to remove these supernumerary teeth should be based on a risk/benefit analysis similar to that of third molars.

Parotid fistula – an extra-orally draining infected dentigerous cyst associated with a supernumerary fourth molar in ascending ramus

An infected cyst, associated with a supernumerary fourth molar in the ascending ramus of the mandible, presented with parotid swelling, trismus and pain. It was managed as a parotid infection but recurred and a draining pre-auricular sinus developed, which was thought to be a parotid fistula. This was managed by cautery, followed by excision of the fistula, both of which were unsuccessful. Following this, further investigations revealed that the cause of the facial sinus was in fact a cyst associated with a mandibular fourth molar in the posterior ascending ramus. The tooth was extracted, via a pre-auricular extra-oral approach, under general anaesthetic. This case shows how a dental panoramic radiograph can be extremely helpful at ruling out certain pathology. It also demonstrates how the symptoms of an infection arising from a tooth in the ramus may be misdiagnosed as salivary gland pathology.

Kissing molars: An unusual unexpected impaction

Impacted molars have been widely reported. However, kissing molars is a rare finding which refers to impacted molars which have occlusal surfaces contacting each other in a single follicular space and roots pointing in opposite directions as reported in this case. This is the second case of kissing molars involving third and fourth molar and the only case fulfilling the criteria of kissing molars.

Three Cases of Distomolars

The Frequency with which impacted supernumerary teeth are encountered in a clinical setting is relatively high, with the majority of such cases occurrig in the median maxillary region, and very few in the molar region. In the molar region, mandibular distomolars (fourth molars) are very rare. Although a small number of case reports have described impacted supernumerary distomolars, very few have compared third molars and distomolars. Herein, the authors report two cases involving mandibular distomolars and one case a maxillary distomolar. In each of these cases, the third molar and distomolar were extracted and a macroscopic morphological analysis conducted. The results were then compared with those of the latest available literature.

Bilateral maxillary fused second and third molars: a rare occurrence

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.

Occurrence of fourth mandibular molars bilaterally and a supernumerary tooth in premolar region: A rare case

To present a rare case of fourth molar bilaterally and a supernumerary tooth in #35 region in the mandible. Brief review of the literature; presentation of the clinical data of the patient and images of the case. Supernumerary fourth molars are rare anomalies of the maxillofacial complex that are more common in the maxilla than in the mandible. Panoramic radio graphs of a female patient aged 38 years revealed the presence of two impacted bilateral mandibular fourth molars and unilateral supernumerary tooth. The supernumerary teeth had normal tooth morphology with regard to their crowns and roots and were similar to the existing third molars and premolars.

Prevalence and Management of Fourth Molars: A Retrospective Study and Literature Review

To evaluate the prevalence of fourth molars and determine if there are differences in occurrence with respect to gender, race, laterality, and site. The charts and panoramic radiographs of all patients referred for third molar consultation between November 2008 and October 2010 at Misawa, US Air Base, Japan were reviewed and data collected included age, gender, and race. Inclusion criteria were minimum age of 18 years and no history of prior third molar surgery. If fourth molars were present, their number, location, size, and shape were noted. Patients with fourth molars were compared to patients without fourth molars with respect to gender and race. Percentages were calculated for laterality and site of occurrence as well. If differences were observed in these parameters, the χ(2) test was used to evaluate if the observed differences were statistically significant. Four hundred nine patients met the inclusion criteria and their charts and panoramic radiographs were reviewed. Fourth molars were observed in 2.2% of the patients. Their prevalence was slightly higher in males (2.2%) than in females (2.1%). They were notably more common in black patients (6.4%) than in whites (0.9%) (P < .005) and they presented more often in the maxilla (78%) than in the mandible (22%) but this difference was not statistically significant (P < .09). Most patients (55%) with fourth molars had them unilaterally. The maxillary fourth molars were typically peg-shaped and small, while the mandibular ones resembled miniature mandibular third molars. The prevalence of fourth molars in this population is 2%. They appear to be more common in black patients and tend to occur mostly in the maxilla unilaterally. When present, the decision to remove these supernumerary teeth should be based on a risk/benefit analysis similar to that of third molars.

Resorptive Tooth Root Lesions in the Malayan Tapir (Tapirus indicus)

Facial abscessation and osteomyelitis due to dental disease is commonly seen in the Malayan tapir (Tapirus indicus), but little is known about the prevalence or etiology of these lesions. To determine the prevalence of dental ailments, 56 skulls and mandibles of deceased Malayan tapirs were visually and radiographically evaluated. Dental lesions were scored according to severity, and individuals were classified according to their age (juvenile/ young adult/adult) and origin (captive/free ranging). All of the lesions identified were of a resorptive nature. seemingly originating at the cementoenamel junction and burrowing towards the center of the tooth. Overall, 27% of the investigated skulls presented radiolucent dental lesions. The prevalence among captive animals was 52% (13/25), while only 6% (2/31) of the free-ranging tapirs had dental lesions. The second, third, and fourth premolars and first molar were the teeth most commonly affected, and the mandibular teeth were more often involved than the maxillary dentition. This study demonstrates a high prevalence of resorptive dental lesions in captive Malayan tapirs and provides a strong indication that age and captivity are significant risk factors in the development of these lesions. Dental disease, Malayan tapir, radiology, resorptive lesions, Tapirus indicus.

Pseudantechinus mimulus: a little known dasyurid marsupial

Information has been gathered from a small number of specimens currently recognised as Pseudantechinus mimulus, 18 of which are registered in museum collections. The distribution of these specimens has been mapped and a more defined area than Alexandria Station proposed as the locality of collection of the holotype. Dental characteristics of P. mimulus, by which it was distinguished from P. macdonnellensis, have been examined and found to be more variable than previously thought. A difference between the two species was found in the morphology of the upper fourth molar. P. mimulus appears to be a seasonal breeder. Birth of the young probably occurs in August and September. The penis of P. mimulus is superficially similar to that of P. macdonnellensis. Both species have an appendage on the penis, but in P. mimulus the appendage may be shorter than that of its congener.

An odontometric study on the maxillary molars in Australian marsupials. -I. The koala (Phascolarctos cinereus)

Crown dimensions of the maxillary molars were measured in the koala (Phascolarctos cinereus). There were no significant differences in crown diameters between the first and second molars, however the fourth molars were reduced in all crown diameters. The third molar was smaller than the first or second molars in buccolingual crown diameters but there were no significant differences in mesiodistal crown diameters. It is proposed that the similar shapes of the first and second molars are associated with similar types of masticatory activity involving these teeth, The shape of the third molar, which is reduced in size buccolingually, may be linked to the koala's occlusal function which is characterized by a condylar action that leads to differences in movement between opposing anterior and posterior molar teeth during the occlusal stroke. The fourth molar, the smallest of the molar teeth in crown diameter, erupts significantly later than the other molars, and its reduction may be explained by the terminal and distal reduction theories. It is proposed that the pattern of molar morphology in the koala is associated with both masticatory activity linked to its characteristic occlusal function, as well as reflecting the sequence of tooth emergence.

A Case of Impacted Supernumerary Fourth Molar in the Bilateral Mandibular Ramus

The occurrence of multiple supernumerary teeth in individuals without any associated syndrome is rare. In this report, a rare case of a 48-year-old woman who had an impacted supernumerary fourth molar in the bilateral mandibular ramus is described. She presented with a swelling in the left cheek region. Radiographic examination revealed an impacted supernumerary tooth in the left mandibular ramus with pericoronal resorption of the bone, suggesting peripheral inflammation. She also had an impacted supernumerary tooth on the right side. After administering an antibiotic and antiinflammatory drug, tooth extraction was performed under general anesthesia.

Contribuição ao Estudo dos Quartos Molares Relato de Caso

Fourth molars can be defined like supernumerary teeth that occur distally to the last third molars. Although a little register in databases, the fourth molars had been describe for more than one century. The purpose of the study was to help in analysis to the fourth molars, specially mandibulary ones, through a case report and a literature review.

Supernumerary molar teeth: observations in the skulls.

To study the prevalence of supernumerary molar teeth in the skull collection of the Zimbabwe Museum of Human Sciences. Cross sectional anatomical observations on human skulls. Zimbabwe Museum of Human Sciences, Harare, and the Department of Anatomy, University of Zimbabwe, Mount Pleasant, Harare. 153 skulls with intact maxillae and 112 mandibles from the skeletal collections of the Zimbabwe Museum of Human Sciences representing the Black Zimbabwean population. Observations on the presence and location of supernumerary molars in the upper and the lower jaws of the human skulls as well as the diameters of supernumerary molars. Two fourth molars were observed in two upper jaws and their prevalence was 0.76%. One fully erupted fourth molar was observed on the left side of the upper jaw distal to the third molar in the alveolar arch of the female skull aged 40 years. Another impacted fourth molar was observed on the right side of the upper jaw of the female aged less than 25 years and was present on maxillary tuberosity. No fourth molars were observed in lower jaw collections. It appears that the supernumerary molars occur rarely. It would be appropriate to evaluate the prevalence of supernumerary teeth in Zimbabwean population based on clinical and radiological examination rather than observations in the skulls.

Bilateral Distomolars in the Maxilla: Computed Radiographic and Cone-beam CT Findings

Distomolar (also known as the fourth molar) is an abnormality in the number of teeth. This finding is usually present on one side of the maxilla, and is comparatively rare as a bilateral finding. We encountered a case of bilateral maxillary distomolars on pantomography. The image reading reports of pantomography and cone-beam CT were created using the reporting system of our radiology department. As we observed panoramic computed radiography, we identified bilateral impacted third molars in the maxilla, with distomolars adjacent to each. Supernumerary teeth displayed normal tooth morphology with regard to crowns and roots but were slightly smaller than the third molars. On cone-beam CT, distomolars were found behind the third molar on both right and left sides of the maxilla. Distomolars were completely impacted, and parts of the roots were near the maxillary sinus on 3D cone-beam CT images.

Analysis of dental anomalies in the Siberian mole, Talpa altaica (Insectivora, Talpidae)

We re-examined tooth variation in specimens of the Siberian mole, Talpa altaica, from the collection of the Siberian Zoological Museum and discuss the mechanisms of dental evolution. The number of teeth counted in 1789 specimens ranged from 34 to 47, and supernumerary, absent, and connate teeth were observed. The most frequent tooth anomaly was an absent tooth in the premolar region (200 maxillary first premolars and 190 mandibular third premolars), which does not support Fujita and Kirino's terminal reduction hypothesis in the mandible [Fujita T, Kirino T. Ha No Kaibougaku. 21st ed. Tokyo: Kanehara Publishers Inc.; 1976 (in Japanese)]. Supernumerary teeth were found in premolar rows and in the incisor and molar regions. An maxillary fourth molar, positioned distal to the normal third molar, was thought to result from a genetically programmed atavistic event during the natal stages. Connate teeth were observed only in the premolar rows and were thought to have developed with the fusion of two independent tooth germs. Connate premolars appeared to result from an expression of an incomplete division of tooth germ at an early developmental stage or a reunion of independent tooth germs, based on the morphological similarity of the normal and supernumerary premolars. These extraordinarily frequent tooth anomalies of T. altaica are of much interest both in terms of tooth development and classification.

Concrescence of a mandibular third molar and a supernumerary fourth molar: Report of a rare case

Concrescence represents a rare developmental anomaly in which two fully formed teeth are joined along the root surfaces by cementum. Maxillary molars are the teeth most frequently involved, especially a third molar and a supernumerary tooth. Very few cases have been reported about the concrescence of a third molar and a supernumerary tooth. According to our current knowledge, this case report is the first in the literature in which concrescence is observed between a third molar and a supernumerary fourth molar in the mandible.