The tori of the mouth and ear: A review

Mandibular torus thickness associated with age: Postmortem computed tomographic analysis

Age estimation is an essential step in identifying human corpses. Several mandibular landmarks have been highlighted as skeletal sites for age estimation since aging causes morphological changes. Reports suggest that mandibular torus size may be associated with aging; however, thorough investigation has not been performed owing to the difficulty in measuring it. Therefore, this study aimed to determine the association between age and mandibular torus thickness using postmortem computed tomography data from Japanese corpses. This study included 2,792 corpses with mean (standard deviation) age of 58.0 (22.4) years (range, 0-101 years) and 67.6 % males. Further, 2,662 (95.3 %), 14 (0.5 %), 59 (2.1 %), and 57 (2.0 %) corpses were in the permanent, mixed, primary, and predental dentition periods, respectively. Multivariable analysis was performed to quantify the impact of age on mandibular torus thickness, adjusting for sex, height, weight, and occlusal contact status. The model also included an interaction term between age and occlusal status because of the potential effect modification by occlusion. Results of the multivariable regression analysis showed that mandibular torus thickness increased with age (the regression coefficients (95 % confidence interval) were 0.6 (0.2-1.0), 0.7 (0.3-1.0), 1.0 (0.6-1.4), 1.3 (0.9-1.7), 1.3 (0.8-1.8), and 1.1 (0.4-1.7) for age groups 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years, respectively), especially in males with occlusal contact. A significant association between mandibular torus thickness and age, modified by occlusal status and sex, was identified. Therefore, data regarding the thickness of the mandibular torus and occlusal status may be useful for age estimation in human corpses.

Craniofacial Osteomas: From Diagnosis to Therapy

An osteoma is a benign bone lesion with no clear pathogenesis, almost exclusive to the craniofacial area. Osteomas show very slow continuous growth, even in adulthood, unlike other bony lesions. Since these lesions are frequently asymptomatic, the diagnosis is usually made by plain radiography or by a computed tomography (CT) scan performed for other reasons. Rarely, the extensive growth could determine aesthetic or functional problems that vary according to different locations. Radiographically, osteomas appear as radiopaque lesions similar to bone cortex, and may determine bone expansion. Cone beam CT is the optimal imaging modality for assessing the relationship between osteomas and adjacent structures, and for surgical planning. The differential diagnosis includes several inflammatory and tumoral pathologies, but the typical craniofacial location may aid in the diagnosis. Due to the benign nature of osteomas, surgical treatment is limited to symptomatic lesions. Radical surgical resection is the gold standard therapy; it is based on a minimally invasive surgical approach with the aim of achieving an optimal cosmetic result. Reconstructive surgery for an osteoma is quite infrequent and reserved for patients with large central osteomas, such as big mandibular or maxillary lesions. In this regard, computer-assisted surgery guarantees better outcomes, providing the possibility of preoperative simulation of demolitive and reconstructive surgery.

Practical Approach to Radiopaque Jaw Lesions

Radiopaque lesions of the jaw are myriad in type and occasionally protean in appearance. In turn, the radiologic analysis of these lesions requires a systematic approach and a broad consideration of clinical and imaging characteristics to enable reliable radiologic diagnosis. Initially categorizing lesions by attenuation pattern provides a practical framework for organizing radiopaque jaw lesions that also reflects important tissue characteristics. Specifically, the appearance of radiopaque lesions can be described as (a) densely sclerotic, (b) ground glass, or (c) mixed lytic-sclerotic, with each category representing a distinct although occasionally overlapping differential diagnosis. After characterizing attenuation pattern, the appreciation of other radiologic features, such as margin characteristics or relationship to teeth, as well as clinical features including demographics and symptoms, can aid in further narrowing the differential diagnosis and lend confidence to clinical decision making. The authors review the potential causes of a radiopaque jaw lesion, including pertinent clinical and radiologic features, and outline a simplified approach to its radiologic diagnosis, with a focus on cross-sectional CT. An invited commentary by Buch is available online. ^©RSNA, 2021.

Early recurrence of mandibular torus following surgical resection: A case report

INTRODUCTION AND IMPORTANCE

Tori are benign bony outgrowths that occur in different locations along the mandible and maxilla. Their origin is still uncertain; however, various hypotheses have been put forward, including male gender or mechanical overload. Recurrence of a torus after surgical resection is rarely described, and even less rapidly after a procedure.

CASE PRESENTATION

We present here the case of a 52-year-old patient who presented voluminous mandibular tori on the lingual side. The tori recurred very rapidly after the first resection surgery and with the same initial volume. Pathological examinations confirmed the histological type. The identified risk factors were excessive fish consumption, occlusal overload factors, and male gender. The patient then underwent a second surgery associated with a mouth guard in order to treat bruxism. There was no recurrence after one year of follow-up.

CLINICAL DISCUSSION

This case report highlights the fact that there is still a lack of understanding of the risk factors associated with torus. However, several studies have been able to understand certain genetic or dietary mechanisms in the genesis of these exostoses.

CONCLUSION

This case emphasizes the importance of mechanical overload in the recurrence of exostoses, which, coupled with dietary, gender, and ethnic factors, may be responsible for recurrence in this patient. The detection of factors associated with the risk of recurrence is a major challenge.

Correlations between dental wear and oral cavity characteristics: Mandibular torus, palatine torus, and oral exostoses

OBJECTIVE

This study evaluates the correlations amongst mandibular torus, palatine torus, oral exostoses to dental wear/loss and temporomandibular damage.

METHODS

The sample consists of 504 skulls from the Hamann-Todd Osteological Collection; 223 African American and 281 European Americans aged between 30 and 80 years. The sample was analyzed using Pearson's Chi-square for significance of sex, age, ancestry, and wear as well as the interactions between the demographic variables and the presence of mandibular torus, palatine torus and oral exostoses.

RESULTS

Wear was statistically significant by age and sex but not ancestry. The maxillary exostoses varied significantly by age, ancestry and wear but not sex. Mandibular torus frequencies varied significantly by wear, sex and ancestry. The palatine torus varied significantly across wear groups, sex and ancestry.

DISCUSSION

The etiology of nonmetric oral cavity characteristics, mandibular torus, palatine torus and oral exostosis, is complex. The degree to which traits' presence and expression is the result of genetic and environmental interactions is not fully understood. More than age, sex or ancestry, the degree of dental wear and tooth loss influences the presence and expression of the oral cavity traits. The sample can be characterized as the presence of exostoses in higher frequencies in young African American males with little tooth loss. Males of both ancestral groups with heavy wear have higher frequencies of mandibular tori than females. The palatine torus is more common in edentulous European American females.

Images in medicine: torus palatinus

A 56 year old African-American female with history of well-controlled hypertension and hyperlipidemia presented to the office for an annual physical examination. She did not have any complaints. She reported being compliant with her medications, exercised daily at her local gym, and maintained a low salt diet. She visits her dentist every 6 months and has had a few fillings in her premolars in the past. On physical examination, her vital signs were normal and the entirety of her physical examination was normal with the exception of her oropharynx. Throat examination revealed a 2 × 1 cm midline hard palate swelling that was bony hard in consistency and covered by normally appearing oral mucosa. It was diagnosed as a torus palatinus. The patient was unaware of its presence and denied being informed about it by her dentist on any visit. She was also educated about the diagnosis and safety-netted by being informed about red-flags that would prompt investigation such as change in size or shape.

Asymmetric bone remodeling in mandibular and maxillary tori

OBJECTIVES

Tori are frequent paucisymptomatic bony outgrowths of the oral cavity in three locations: torus palatinus (TP), mandibularis (TM), and maxillaris (TMax). Their usually described histological characteristics are unspecific: normal cortical bone with more or less trabecular bone. The aim of this study was to describe tori's specific morphological and histomorphometric characteristics.

MATERIALS AND METHODS

Histological characteristics in a series of 18 tori collected after surgical removal were analyzed. Microcomputed tomography provided a 3D analysis. Mineral apposition rate (MAR) was measured after double tetracycline labeling. Osteoid tissue was identified by Goldner's trichrome and osteoclasts by the tartrate resistant acid phosphatase identification in undecalcified sections. Iron and aluminum were detected by histochemical staining methods. Osteoid thickness and MAR were determined at the outer surface of the torus and in the Haversian canals.

RESULTS

Tori appeared made of lamellar Haversian bone in 16/18 cases. Osteoid thickness did not differ between the outer surface and within the canals. An asymmetric bone remodeling was observed in the Haversian canals of 15 tori: osteoid seams were deposited on the side close to the free torus surface, and Howship's lacunae with numerous osteoclasts were observed on the opposite side. A high MAR was found at the surface of the tori and within the canals. There was no iron or aluminum deposit.

CONCLUSIONS

Tori may be characterized by a specific asymmetric bone remodeling which seems to determine their shape.

CLINICAL RELEVANCE

This finding could constitute a specific histological feature allowing to differentiate tori from exostoses. Graphical abstract.

Developmental Disorders Affecting Jaws

Teeth are housed in mandible and maxilla and are known to undergo variations in clinical presentation depending on the degree of abnormality during growth and development. It is essential to identify these variations in normal anatomy so that appropriate treatment can be initiated to address the anomaly. Some normal anatomic variations are harmless and best left alone, whereas others require intervention. Radiology plays a vital role in identification of such anomalies. This article focuses on the diagnostic radiographic interpretation and strategies to include pertinent differential diagnosis. Also discussed is the importance of advanced imaging and its appropriateness in the diagnosis and interpretation.