Kissing molars: report of three cases and new prospective on aetiopathogenetic theories

Kissing molars (KMs) is an extremely rare condition of impacted third molars, pointed in the opposite direction in a single follicular space; it consists exactly in a full impacted of permanent molars which occurs only in the lower jaw. Actually, about less than thirty cases have been reported in scientific literatures. The aetiology and pathogenesis of this pathological double dental inclusion remain unknown; above all events that lead two molars to appear, as KMs remain mysterious. The association to metabolic connective diseases such as mucopolysaccharidosis was emphasized. KMs considered as an isolated event, may be associated to an abnormal position of the tooth-bud from lower permanent molars, or fourth supernumerary tooth (distomolar). Recently, hyperplastic dental follicle (HDF), with a down regulation of matrix metal-proteinases and up regulation of several genes of collagens, has been mentioned in association with KMs. In this paper, after having analyzed three new cases of KMs that have been treated, we report a new hypothesis. This last is based on the failure in the dental follicle's ability to initiate or continue properly resorption of the overlying alveolar bone, by many exogenous factors which may act on eruptive phase that would lead to its rotation with its contents coming out a pathological situation of KMs. The therapy of choice is related to the surgical removal of KMs through a double odontectomy with transalveolar method. Other treatments can be, eventually, orthodontic therapy of the impacted teeth and a radiological follow-up without surgery.

HSP70 expression in dentigerous cyst, odontogenic keratocyst, and ameloblastoma

Heat shock proteins (HSPs) work as molecular chaperones that can assist cells to deal with stressful situations. Members of the HSP70 family can regulate cell growth and transformation and are involved in the maintenance of cellular homeostasis. In view of the distinct clinical behavior of odontogenic lesions, the objective of the present study was to investigate the immunohistochemical expression of HSP70 in these lesions. In this study, 70 formalin-fixed paraffin-embedded tissue blocks of odontogenic lesion-16 unicystic ameloblastomas (UAs), 17 solid ameloblastomas (SAs), 18 odontogenic keratocysts (OKCs), and 19 dentigerous cysts (DCs)-were reviewed by immunohistochemistry for HSP70 staining. In this study, HSP70 immunostaining was evident in all groups of the specimen. Mean percentage of HSP70 staining in SAs (84.2 ± 11.3) and OKCs (83.4 ± 6.8) were significantly higher than UAs (64.4 ± 9.8) and DCs (12.6 ± 10.2) (p = 0.00). But, there was no statistically significant difference between HSP70 expression in SAs and OKCs. The result of this study proposes that high expression rate of HSP70 has a role in the pathogenesis of ameloblastoma and OKC and is one of the reasons for the aggressive behavior of ameloblastoma and high recurrence role of OKC, reinforcing the classification of OKC as an odontogenic tumor.

Relationship between the positions of impacted third molars and the presence of dentigerous cysts

The objective of this study was to assess the association between the histopathological diagnoses of dentigerous cysts and pericoronal follicles and the positions of impacted third molars. The sample comprised 151 cases, diagnosed as dentigerous cysts and pericoronal follicles. Most patients were female (70.9%), white (90.1%), and age 20 years or older (63.6%). Ninety-eight cases (64.9%) were diagnosed as pericoronal follicles and 53 (35.1%) as dentigerous cysts. Teeth that developed dentigerous cysts were predominantly located in the mandible (84.9%), in a mesioangular position (49.1%), and in the 20- to 29-year age group (66.0%). The mandible seems to be the most frequent location of impacted teeth, probably because mandibular tooth eruption is more difficult, as well as dentigerous cysts, probably because the long duration of impaction increases the exposure to inflammatory stimuli and, thus, the potential for formation of dentigerous cysts. The findings also suggest that the incidence of dentigerous cysts tends to increase with age, especially for mandibular teeth in mesioangular positions.

Twist expression in dentigerous cyst, odontogenic keratocyst, and ameloblastoma

Epithelial-mesenchymal transition (EMT) is a process which is associated with a loss of intercellular adhesion, acquired mesenchymal shape, and increased motility by epithelial cells. Twist is one of the key regulators of EMT.In view of the distinct clinical behavior of odontogenic lesions, the objective of the present study was to investigate the immunohistochemical expression of Twist in these lesions. In this study, 70 formalin-fixed, paraffin-embedded tissue blocks of odontogenic lesion consisting of 16 unicystic ameloblastomas (UA), 17 solid ameloblastomas (SA), 18 odontogenic keratocysts (OKC), and 19 dentigerous cysts (DC) were reviewed using immunohistochemistry for Twist staining. In this study, Twist immunostaining was evident in all groups of the specimens except the dentigerous cyst group. Twist expression was seen in 58.8 % (10/17) of SA, 50 % (8/16) of UA, and 44.4 % (8/18) of OKCs. 23.5 % of SA, 18.8 % of UA, and 16.7 % of OKCs showed Twist expression in more than 50 % of cells. Statistical analysis showed that Twist expression levels were significantly higher in ameloblastomas (SA and UA) and OKCs than dentigerous cysts (P = 0.002). There were no significant differences between Twist expression in SAs, UAs, and OKCs (P > 0.05). The results of this study propose that the high expression rate of Twist plays a role in the pathogenesis of ameloblastomas and OKCs and might be one of the reasons for the aggressive behavior of ameloblastomas and high recurrence of OKCs and could reinforce the classification of OKC as an odontogenic tumor.

Oral and maxillofacial lesions in a Thai pediatric population: a retrospective review from two dental schools

OBJECTIVE

To determine the prevalence of oral and maxillofacial lesions in a Thai pediatric population.

MATERIAL AND METHOD

Oral biopsy records from pediatric patients between the ages of 0 and 15 years in the files ofFaculty of Dentistry, Mahidol University, and the files of Faculty of Dentistry, Khon Kaen University were reviewed. The patients were divided into three age groups, including 0 to 5, 6 to 10, and 11 to 15 years. Excluding the diagnosis of normal tissues, the oral and maxillofacial lesions were classified into nine categories.

RESULTS

Of 13,050 biopsied oral and maxillofacial lesions, 1,389 cases (10.6%) came from pediatric patients. The largest number of lesions was odontogenic cysts and tumors, followed by inflammatory and reactive lesions, and salivary gland pathology The top ten most prevalent lesions contributed 73% of all oral biopsies. The most common lesion was dentigerous cyst, followed by mucocele and pyogenic granuloma.

CONCLUSION

The vast majority of oral diseases in children were benign and related to either developmental or tissue reaction, while malignant lesions were found in a very small proportion of all oral biopsies.

Bilateral impacted inverted mesiodens associated with dentigerous cyst

Mesiodens, the most common type of supernumerary tooth, usually results in malocclusion, poor esthetics and cyst formation. The occurrence of a dentigerous cyst around the crown of an unerupted supernumerary tooth is infrequent. We present a case of a dentigerous cyst associated with a nonsyndromic bilateral impacted inverted supernumerary tooth in a 13-year-old boy. A thorough clinical workup, including 3-D reconstruction image and histological examination confirming the features of a dentigerous cyst is presented in this report.

Eruption of impacted permanent teeth after treatment of a dentigerous cyst: a case report

Dentigerous cysts are the most common developmental odontogenic cysts. It is a benign and asymptomatic intraosseous lesion that affects the bones of the maxillofacial complex, interfering with tooth eruption. Although enucleation is the treatment of choice, marsupialization is the better option for large cysts involving unerupted permanent teeth. The purpose of this article is to report the eruption of impacted permanent mandibular right canine and first and second premolars after marsupialization of an infected dentigerous cyst. Two years after marsupialization and orthodontic treatment, the cyst disappeared and the canine and premolars erupted uneventfully.

Immunophenotypic characterization and distribution of dendritic cells in odontogenic cystic lesions

OBJECTIVE

To analyze the expression and distribution patterns of mature dendritic cells (mDCs) and immature DCs (imDCs) in radicular cysts (RCs), dentigerous cysts (DtCs), and keratocystic odontogenic tumors (KCOTs).

MATERIALS AND METHODS

Forty-nine odontogenic cystic lesions (OCLs) (RCs, n = 20; DtCs, n = 15; KCOTs, n = 14) were assessed using the following markers: S100, CD1a and CD207 for imDCs; and CD83 for mDCs.

RESULTS

Almost all cases were S100, CD1a, and CD207 positive, whereas 63% were CD83 positive. RCs presented greater number of immunostained cells, followed by DtCs, and KCOTs. The number of S100+ cells was greater than both CD1a+ and CD207+ cells (P < 0.001), which showed approximately similar amounts, followed by lower number of CD83+ cells (P < 0.001) in each OCL type. Different from S100+ cells, both CD1a+ and CD207+ cells on the epithelium (P < 0.05) and CD83+ cells on the capsule (P < 0.05) were preferentially observed. In RCs, significant correlation was found between the thickness epithelium with S100+ and CD1a+ cells, and between the degree of inflammation with CD83+ cells.

CONCLUSIONS

Dendritic cell populations in OCLs can be phenotypically heterogeneous, and it could represent distinct lineages and/or functional stages. It is suggested that besides DC-mediated immune cell interactions, DC-mediated tissue differentiation and maintenance in OCLs should also be considered.

[Dentigerous cyst in the mixed dentition]

Dentigerous cyst is a developmental odontogenic cyst, which apparently develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown of an unerupted tooth. Management of dentigerous cyst in primary dentition needs special consideration regarding the preservation of the developing permanent tooth buds. A case of dentigerous cyst is reported in primary dentition of a 7-year-old female patient and its management. By extracting the infected primary teeth, opening the cyst and ensuring continuous drainage, it is possible to achieve spontaneous eruption of the involved permanent teeth into the dental arch even if they are badly dislocated. Simultaneous with the eruption of the permanent teeth, ossification of the bony defect can take place. The reparatory process is completed in one to two years, during this time the patient has been given a space-maintainer.

Management of a deeply impacted mandibular third molar and associated large dentigerous cyst to avoid nerve injury and improve periodontal healing: case report

As dentigerous cysts increase in size, the risk of postsurgical complications increases as well. Emphasis is usually placed on the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the large residual bone defect. However, influence on the periodontal status of neighbouring teeth should also be taken into account. In this article, we present an interdisciplinary, safe, minimally invasive approach to treating large dentigerous cysts associated with deeply impacted third molars. A dentigerous cyst is an epithelial-lined pathologic cavity that develops in association with the crown of an unerupted tooth and appears radiographically as a well-circumscribed pericoronal radiolucency. The cyst not only inhibits the eruption of the associated tooth (usually, a mandibular third molar), but can also carry it to unusual positions in the jaw. Dentigerous cysts may enlarge causing extensive bone resorption and even pathologic fracture. The greater the size of the cyst, the higher the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the postoperative bone defect.7,8 Moreover, the removal of large cysts can lead to a severe infrabony defect at the root surface of adjacent teeth, jeopardizing their long-term periodontal health. "Orthodontic extraction" is a combined orthodontic-surgical approach that decreases the risk of neurologic complications and facilitates the surgical extraction of impacted mandibular third molars that are in close contact with the mandibular canal, even when associated with cystic lesions.13 This case report shows that the interdisciplinary approach is also effective in preventing periodontal breakdown on the distal surface of the adjacent second molar.

Large erupting complex odontoma in a dentigerous cyst removed by a piecemeal resection

Odontomas (ODs) are the most frequent odontogenic tumors in Western societies, they are often asymptomatic and discovered during routine radiography The purpose of this report was to describe the case of a 10-year-old child with an odontoma within a dentigerous cyst (DC). The patient presented with a 1-week history of painful swelling involving the right mandible and cheek. An intraoral examination revealed a defect of the oral mucosa behind the permanent mandibular first molar, which resembled an exposed alveolar bone or tooth remnants. Clinical and radiographic evaluation revealed a large erupting OD associated with a dentigerous cyst. The OD was separated into pieces and enucleated together with the dentigerous cyst to preserve the mandible's integrity and because of the patient's age. This is the first report of an erupting OD associated with a DC in a child. Surgical removal might be a challenge when large ODs are encountered.

Dentigerous cyst of the maxilla with impacted tooth displaced into orbital rim and floor

We report a case of dentigerous cyst of the maxilla and maxillary sinus that caused the ectopic displacement of an unerupted tooth into the orbital rim and floor. After an incisional biopsy, marsupialization of the lesion promoted its involution and stimulated osteogenesis. This in turn simplified the surgical enucleation of the specimen and removal of the unerupted tooth without the excessive loss of the bony contours of the maxilla.

A pigmented dentigerous cyst in a patient with multiple dentigerous cysts of the jaws: a case report

AIM

The aim of this article is to report an unusual and interesting case of non-syndromic multiple dentigerous cysts of the maxilla and mandible associated with melanin pigment and melanocytes in the epithelial lining in one of the cysts. In addition, embryologic aspect and origin of melanocytes are briefly discussed.

BACKGROUND

Dentigerous cysts are the second most common odontogenic cysts after radicular cysts. They are usually solitary with multiple cysts reported on occasion in association with syndromes. While melanocytes and melanin-pigment are widely distributed in the skin, the nervous system, certain types of mucosa, uveal tract, and other areas, they are not normally present within bone in mammals.

REPORT

A 37-year-old Iranian male was referred to an oral surgeon by his dentist for evaluation and treatment of multiple cyst-like radiolucent lesions around the crowns of some unerupted permanent teeth in both maxillary and mandibular anterior areas. The biopsy revealed numerous granules of melanin-pigment distributed throughout the epithelial lining of one of these cysts in addition to the characteristic histopathologic features of adentigerous cyst. Histochemical analysis confirmed the pigment was melanin, and many of the cells containing melanin were immunohistochemically positive for s-100 protein.

SUMMARY

Although the specific origin and pathologic significance of the melanocytes described here cannot be explained, it may be of interest for future investigations.

Clinicopathological study of dentigerous cysts in Singapore and Malaysia

This was a retrospective study of dentigerous cysts in people from the Singapore-Malaysian region. The purpose of this study was to present the clinicopathologic features of dentigerous cysts in the Oriental population and to compare these data with those from other reported studies. Biopsy records from 1981 to 1993 of 119 cases of dentigerous cysts from patients in Malaysia and Singapore showed that 36.1% of patients were female and 63.9% patients were male. Among patients with cysts, 70.5% were Chinese, 23.2% were Malays, 2.7% were Indian and 3.6% were other ethnic groups. The mean age of these patients was 30.2 +/- 17.3 years with a peak incidence occurring in the second and third decades. The location of the lesions was almost equal to the maxilla (50.9%) and the mandible (49.1%). There was a marked predilection for the posterior mandible (42.7%) followed by the anterior maxilla (38.2%). Histologically, 90.8% of the cysts were lined by a non-keratinised stratified squamous epithelium. The cyst linings were mainly thin (90.0%) with 38.7% of cases having a mixed thick and thin lining. Mucous metaplasia was observed in 9 (7.6%) cases. Rushton bodies were seen in 3.4% of cases. Cholesterol clefts in the epithelial lining and lumen were found in 16.8% cases while 12.6% of cases exhibited cholesterol clefts in the cyst wall. Other cellular structures within the cyst wall were lymphocytes (66.4%), plasma cells (52.1%), Russell bodies (16.0%) and histiocytes (4.2%). Odontogenic keratocysts were observed in 5.0% of cases. One case of adenomatoid odontogenic tumour was also observed. Epithelial atypia was seen in 9.2% of cases, islands of stratified squamous epithelial cells in 8.4% of cases while one case showed a combination of these two features. In conclusion, some clinical features seen in this study are similar to that for the Caucasian population such as prevalence in male, peak incidence in the second and third decades and the predilection for the posterior mandible and anterior maxilla. Histopathologically, odontogenic keratocyst and adenomatoid odontogenic tumour were observed in dentigerous cysts.

Adenomatoid odontogenic tumour associated with dentigerous cyst - unusual case report

The adenomatoid odontogenic tumor is a relatively uncommon lesion which mainly affects females in their second decade of life, exhibiting predilection for the anterior region of the maxilla. The lesion is usually associated with the crown of an enclosed tooth, most commonly the maxillary canine. In this paper we present a case of adenomatoid odontogenic tumor associated with a dentigerous cyst affecting the left maxillary region in a 13-year-old female. The authors also discuss clinical, radiographic, histopathologic and therapeutic features of the case.

Metastatic breast carcinoma discovered in a dentigerous cyst — a case report

This paper reports a patient with a history of breast cancer, who presented with altered sensation to the right lower lip and chin. An orthopantomogram showed a probable dentigerous cyst associated with an unerupted lower wisdom tooth, which was closely related to the inferior dental canal. The tooth and cyst were enucleated under general anaesthesia. The subsequent histopathology report concluded that the cyst contained metastatic adenocarcinoma from a primary breast tumour.

Oligonucleotide microarray analysis of ameloblastoma compared with dentigerous cyst

BACKGROUND

Ameloblastoma is a benign, but locally invasive tumor known for its high rate of recurrence. However, few comprehensive genetic studies have been conducted about its tumorigenesis. Our aim was to identify possible genes involved in the development and progression of ameloblastoma, using microarray analysis with dentigerous cyst as a control.

METHODS

Total RNA was extracted from two fresh dentigerous cysts and ameloblastoma specimens. Following microarray analysis, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on selected genes.

RESULTS

Seventy-three genes were overexpressed and 49 were underexpressed. These genes were divided into categories according to function. The microarray results for 13 selected genes were verified with semiquantitative RT-PCR.

CONCLUSIONS

We identified important genes related to the development and progression of ameloblastoma through a large-scale gene expression analysis. This study will stimulate further investigations on genes significant for early diagnosis and prognosis of ameloblastoma.

Immunohistochemical analysis of the biological potential of odontogenic keratocysts

BACKGROUND

The aim of this study was to analyse the usefulness of detecting important apoptosis and proliferation markers in assessing the biological potential of odontogenic keratocysts (OKC) and thus selecting the optimal diagnostic algorithm for these lesions.

METHODS

Indirect immunohistochemistry and relevant statistical methods were used for analysis of formalin-fixed and paraffin-embedded samples from 98 patients.

RESULTS

Nevoid basal cell carcinoma syndrome (NBCCS) keratocysts were characterized by higher expression of Bcl-2, p27Kip1 and c-erbB-2 as well as by lower proliferative activity measured by Ki-67 in basal cell epithelium and by a lower inflammatory response in comparison with sporadic keratocysts. Dentigerous, radicular and non-specified odontogenic cysts differed from both NBCCS and sporadic keratocysts in a wide spectrum of apoptosis and/or cell cycle-related protein expressions, higher proliferation in the basal cell layer, and vice versa, lower proliferation in the suprabasal cell layer.

CONCLUSIONS

The NBCCS keratocysts have a different immunophenotype from sporadic keratocysts and both types are distinguishable from dentigerous, radicular and non-specified odontogenic cysts. These findings confirm the separate biological potential of these lesions and the results of the immunohistochemical analysis have diagnostic and prognostic implications.