Canines and inflammatory external apical resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of maxillary canines, to prevent it?

JUSTIFICATION: Canines represent corners in the dental arch, and are important features in facial esthetics, as they support the upper lip, wing of the nose, and influence the nasolabial fold and the appearance of facial aging. In the laterality movements, the canines guidance coordinate the opening and closing of the teeth, saving the TMJ from sudden movements. DISCUSSION: As a result of the lack of eruption or the inadequate positioning of the maxillary canine, the loss of the laterality guide may occur, which will then occur in the maxillary lateral incisor, inducing lesions of "occlusal trauma", such as inflammatory root resorption. Likewise, without well positioned canines, there may be premature aging and change in facial esthetics. CONCLUSION: In order to avoid problems with eruption and positioning of the maxillary canines, early diagnosis is made by analyzing their position and their relationship with the other teeth, and in the three-dimensional context of the maxilla, between 8-10 years of age. Preventive measures can create bone space and direction so that the maxillary canines can occupy their position in the dental arch.

Quantitative assessment of morphological changes of dental pulp components of teeth affected by occlusal trauma.

AIM: In the general economy of the stomatognathic system functionality, the occlusal function has an important role, meaning both the dental-dental reports and the dynamic reports interarch-interarch. Because of the interrelationships and inter-dependency that govern the functioning of the biological systems, a pathological change affecting a component of the stomatognathic system produces impaired functioning of the others. The aim of the present study is to assess the morphological changes occurred in the dental pulp components of teeth affected by occlusal trauma. MATERIALS AND METHODS: Fragments of dental pulp coming from 45 patients with occlusal trauma were processed using classical histological techniques (formalin fixation and paraffin embedment) and stained with Hematoxylin-Eosin (HE), Masson's trichrome and anti-CD34 antibody immunostaining, in order to highlight the peripheral zone and central connective tissue of dental pulp morphological changes. A set of parameters namely thickness of peripheral zone components, calcifications, fibrosis and vascular density in the dental pulp were assessed individually and based on three topographical criteria namely the affected tooth, the position on the dental arches and the position according to sagittal plane. RESULTS: There was no correlation between morphological changes of dental pulp and the topography of teeth with occlusal trauma. The size of the peripheral area of the dental pulp and that of its components evolved in the same sense, whether it was growth or decrease. Decrease of the peripheral area was associated with the increase of collagen fibers density, calcium deposits and density of the capillary network. The direct correlation between the amount of collagen fibers and vascular density seems somewhat paradoxical but it can be explained by the reemergence of chronic inflammatory events located in the dental pulp. CONCLUSIONS: It seems that dental pulp morphological changes are not influenced by the teeth with occlusal trauma topography. With one exception (the components of peripheral zone), most of the correlations between the dental pulp morphological changes were only suggested but not validated statistically, which requires further studies on larger groups together with the introduction of inflammatory cell population studies.

Morphological changes of gums in occlusal trauma.

AIM: Occlusal trauma causes major modifications of the coverage periodontium, which in turn reflect on the dental unit. The aim of the present study is to evaluate some of the morphological modifications occurred in the marginal periodontium surrounding teeth affected by occlusal trauma. MATERIALS AND METHODS: Fragments of marginal periodontium coming from 51 patients with occlusal trauma were processed using classical histological techniques (formalin fixation and paraffin embedment) and stained with Hematoxylin-Eosin (HE), Masson's trichrome and anti-CD34 antibody immunostaining, in order to highlight the epithelial and connective tissue changes of gingival mucosa. A set of epithelial and connective tissue morphological parameters were assessed individually and based on three topographical criteria concerning the affected tooth. RESULTS: The epithelium and especially its superficial compartment presented changes depending on the tooth type and the dental arch. Epithelial thickness had the tendency to decrease as the fibrosis in both corium compartments and vascular density in the deep corium compartment were increasing. Leukoplakia present around the affected teeth but not always was related with the tooth type and was more obvious as the superficial compartment of the epithelium was thicker and as fibrosis was more reduced in the papillary compartment of the corium. Vascular density reduced when fibrosis process increased in the corium. CONCLUSIONS: Lesions determined by occlusal trauma and their topography can and are influencing locally the different structures of the surrounding periodontium.

Versatility and Importance of Bichat's Fat Pad in Dentistry: Case Reports of Its Use in Occlusal Trauma.

INTRODUCTION: The knowledge of the anatomy surrounding Bichat's fat pad, as well as its clinical applications, is essential to indicate and to safely perform its removal. This surgery is indicated not only for esthetic purposes, but also for functional reasons. When used properly, Bichat's fat pad is composed of stem cells that have a similar phenotype to adipose stem cells, useful in the treatment of pathologies and/or complications, such as maxillary sinus membrane perforation, oroantral/oronasal communications, peri-implantitis, ulcers, fibrosis of the oral mucosa, soft tissue reconstruction, among others. Due to its location, it is prone to suffer clinically significant pathologies, as well as constant trauma. AIM: The aim of this study is to report two clinical cases and subsequent follow-ups, where bichectomy was performed to avoid dental trauma to mucosal tissues during the masticatory function. Also, literature review on the application of Bichat's fat pad in dentistry is provided. CASE REPORT: Two female patients (20 and 24 years) reported discomfort and constant pain in the oral mucosa caused by dental trauma. At the clinical examination, patient presented augmented and injured mucosa. The surgical sequence of Bichat's fat pad removal, as well as the extra-/intraoral photographic follow-up (8, 15, 30, and 180 days) of the patients is described. CONCLUSION: In order to indicate and/or accomplish surgical procedures involving Bichat's fat pad, it is fundamental to know its anatomy and possible applications, not only for esthetic purposes, but also for functional purposes. The patients showed evident improvements following the removal of Bichat's fat pad. CLINICAL SIGNIFICANCE: Application of Bichat's fat and its removal should be evaluated, being an alternative in patients who constantly undergo mucosal injury during masticatory function.

The influence of traumatic occlusion on the repair process for teeth following subluxation.

BACKGROUND/AIM: Traumatic occlusion (TO) can cause morphofunctional alterations that interfere in the homeostasis of the periodontium. The aim of this study was to assess the influence of TO on the periodontal repair process for teeth following subluxation. MATERIALS AND METHODS: Ninety Wistar rats aged 12 weeks were divided into three groups: control (C), subluxation (S) and subluxation with traumatic occlusion (S+TO). Subluxation was created with an impact force of 900 cN applied by a tensiometer and TO was created with a direct composite resin filling. Healing after two experimental periods of 7 and 21 days was assessed histologically. The Kruskal-Wallis and Dunn post hoc tests were used for group comparison. RESULTS: At 7 days, there was a significant increase in periodontal ligament (PDL) width and amorphous fundamental substance, as well as a significant bone area reduction in groups S and S+TO. After 21 days, there was a significant PDL width increase in group S+TO, and in the percentage of collagen fibres in group S, whereas group S+TO showed a 52% bone area reduction compared to the same group at 7 days. Subluxation with or without TO caused only superficial root resorption. However, only group S+TO showed damage to the repair process of resorbed root areas after 21 days. CONCLUSION: TO can increase damage to the PDL after subluxation and it can also delay the repair process after PDL damage.

Caudal mucogingival lesions secondary to traumatic dental occlusion in 27 cats: macroscopic and microscopic description, treatment and follow-up.

The main aim of this retrospective study was to describe clinical and histopathological findings in cats with mucogingival lesions developed at the contact point of the premolar and molar teeth of the opposite quadrant. Cases were retrieved following manual review of the medical records, dental records and photographic documentation of all feline dental patients visited in the period between February 2001 and August 2011. Cats showing different lesions at different times were calculated as multiple cases. A total of 27 cats (31 cases) with 44 lesions (26 proliferations [59%], 11 clefts [25%] and seven foveae [16%]) were included. Mean age at the time of the first visit was 6.6 years. The lesion object of the study was the main reason for presentation in only five cases (16%). Proliferations showed two different histopathological patterns and had characteristics in common with human oral pyogenic granuloma. Successful treatment was achieved in all cases by removing the occlusal contact by dental extraction or coronal reduction, possibly associated with lesion excision. This study underlines the need for a thorough oral examination and evaluation of dental occlusion in all patients. Causes for the development of traumatic occlusion may include an acquired overbite (possibly secondary to selective dental extraction), congenital or post-traumatic malocclusion, abnormal latero-lateral mobility of the mandible, occlusal drift of the premolar and molar teeth, and/or alveolar bone expansion.

Evaluation of the relationship between bruxism and premature occlusal contacts.

AIM: This study evaluates the relationship between occlusal interferences and premature contacts and bruxism by determining the relationship between unassisted and assisted nonworking interferences. MATERIALS AND METHODS: In this study, 60 subjects (14 males and 46 females) that consisted of 30 bruxers (7 males, 23 females) and 30 nonbruxers (7 males, 23 females) were selected after completion of a questionnaire based on the exclusion criteria. Occlusal interferences in the centric relation and eccentric movements in the two groups were evaluated and recorded. Data were analyzed by SPSS software (version 16) using the Chi-square and paired t-tests. RESULTS: The results showed a statistically significant relationship between bruxism and nonworking interferences (p < 0.05). There was no statistically significant relationship in the centric relation and other eccentric movements (p > 0.05). The number of assisted nonworking occlusal contacts was more than unassisted nonworking occlusal contacts. CONCLUSION: According to the results of this study, there is a relationship between certain types of occlusal interferences (nonworking interferences) and bruxism. Hence, it would be useful to examine occlusal contacts in bruxing patients to eliminate probable causative or contributing occlusal factors. Both assisted and unassisted nonworking occlusal contacts should be evaluated. CLINICAL IMPLICATION: Bruxism is an oral habit that consists of involuntary rhythmic or spasmodic nonfunctional gnashing, grinding or teeth clenching, other than chewing movements by the mandible. Bruxism may lead to occlusal trauma, tooth wear, fracture of the teeth and fillings, and hypertrophy of the masticatory muscles. Treatment of bruxism needs a correct diagnosis. Therefore, it is useful to determine the relationship between occlusal interferences and bruxism in order to prevent its development by adjusting for these interferences.

Hyperocclusion up-regulates CCL3 expression in CCL2- and CCR2-deficient mice.

UNLABELLED: Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We have recently reported that MS induces predominantly C-C chemokine ligand (CCL) 2 expression in PDL tissues, leading, via C-C chemokine receptor (CCR) 2, to MS-dependent osteoclastogenesis in alveolar bone. Thus, we hypothesize that ablation of the CCL2/CCR2 signaling pathway should suppress MS-induced osteoclastogenesis-associated chemokines and alleviate occlusal traumatism. We examined the effect of MS on chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models with CCL2-deficient (CCL2((-/-))) and CCR2-deficient (CCR2((-/-))) mice. Compared with that in wild-type mice, expression of CCL3 in PDL cells and TRAP-positive cells in alveolar bone from CCL2((-/-)) and CCR2((-/-)) mice was up-regulated, even in the absence of MS. Furthermore, the expression of CCL3 and TRAP-positive cells was significantly increased after both 4 and 7 days of hyperocclusal MS loading in CCL2((-/-)) and CCR2((-/-)) mice. Hyperocclusion induced compensatory CCL3 expression and promoted osteoclastogenesis to counterbalance deficient CCL2/CCR2 signaling, suggesting that co-expression of CCL3 with CCL2 may precipitate synergistic, MS-dependent alveolar bone destruction during occlusal traumatism. ABBREVIATIONS: MS, mechanical stress; PDL, periodontal ligament; CCL2, CC chemokine ligand 2 (MCP-1; monocyte chemoattractant protein-1); CCR2, CC chemokine receptor 2; CCL3, CC chemokine ligand 3 (MIP-1α); CCL5, CC chemokine ligand 5 (RANTES).

The effect of experimental occlusal interferences on nerve growth factor levels in periodontal tissues.

OBJECTIVE: To test the hypothesis that experimental occlusal interferences increase the nerve growth factor (NGF) levels in periodontal tissues and cause an up-regulation of preprotachykinin-A (PPTA) mRNA. BACKGROUND: NGF is related to hyperalgesia and inflammation. PPTA mRNA, a primer of substance P, is a possible factor in the aetiology of pain. METHODS: Experimental interferences were created by placing inlays in the right maxillary molars of 15 dogs. The right side molars formed the experimental group. The left side molars served as controls. Three dogs with cavities prepared without changing the occlusion formed a sham group. The dogs in the first group were sacrificed, 3 at each time, after 3, 7, 14, 30, and 60 days. The sham group was sacrificed after 14 days. The levels of NGF in periodontal tissues and PPTA mRNA in the trigeminal ganglions were detected by ELISA and TR-PCR. Comparisons were made with paired t-tests and a multivariate MANOVA test. RESULTS: On all measurement days, there were higher levels of NGF mRNA, PPTA mRNA, and NGF on the experimental than on the control side in 14 of 15 comparisons and in the sham group. NGF production in periodontium was time-dependent. No differences in NGF protein levels were observed between the control and the sham groups. CONCLUSION: The results which need confirmation in further tests are of clinical interest. They indicate that occlusal experimental interferences may be an etiologic factor in oral facial pain by increasing mRNA and NGF protein levels in the periodontal tissues.

Dental wear and oral pathology: possible evidence and consequences of habitual use of teeth in a Swedish Neolithic sample.

Atypical wear and oral lesions were studied in the dental remains from the Middle Neolithic Pitted Ware Culture site Ajvide on the island of Gotland in the Baltic Sea. Teeth (n = 764) from 17 males and 11 females were examined microscopically to document unusual wear, assess wear patterns and oral lesions as evidence of habitual behavior, and determine their effect on the oral health of this population. Five atypical wear types were observed: occlusal facets, occlusal excessive load, labial vertical striae, labial horizontal striae, and interproximal striae. Three oral lesions were recorded: chipping, periapical lesions, and dental tilting. Results indicate that teeth were used in a habitual manner at Ajvide, based on the morphology and regularity of the patterns of atypical wear. Differences were observed between the sexes, indicating gender-related differences in the habitual use of teeth. Some wear categories showed a significant correlation with age, signifying increased or accumulated wear with age. Statistically significant positive correlations were found in the molars between occlusal excessive load wear and periapical lesions as well as tilting. Other apparent links were also observed between chipping and vertical striae as well as excessive load, although these were not significant. This suggests a relationship between dental wear and dental pathologies at this site, suggesting that habitual use of teeth indirectly affected the general oral health at the site. Wear patterns, furthermore, seem to mirror both frequent activities as well as single events.

The effect of physiological nonbalanced occlusion on the thickness of the temporomandibular joint disc: a pilot autopsy study.

STATEMENT OF PROBLEM: The temporomandibular joint (TMJ) disc is often observed to be thicker in temporomandibular disorder (TMD) patients. This clinical observation requires verification. PURPOSE: The purpose of this pilot study was to investigate whether the TMJ disc responds to dysfunctional occlusal changes by an increase in thickness. MATERIAL AND METHODS: Twelve cadaver heads were divided into 2 groups, 1 with physiologically balanced occlusion (BO), 7 cadaver heads and 14 joints, and the other with physiologically nonbalanced occlusion (NO), 5 cadaver heads and 9 joints. The NO group had defining traits, such as reverse articulation or tightly locked occlusion. The latter is an occlusal relationship with drifted, tilted, and/or supraerupted teeth, often seen in patients who have lost posterior teeth. Histological sections from the lateral, center, and medial parts of the joints stained with haematoxylin and eosin were used for measuring the disc thickness. Student t tests and Bonferroni correction were used to compare groups (alpha=.05). RESULTS: All 9 mean thickness values were higher in the NO than in the BO group. According to the t tests, the posterior band was thicker in the lateral (P=.007) and center (P=.015) sections, and the intermediate zone was thicker in the lateral section (P=.008) in the NO than in the BO group. These differences were not significant after Bonferroni corrections. CONCLUSIONS: The results suggest that the TMJ disc has the ability to adapt to alteration of the space between condyle and fossa caused by occlusal changes. Further studies from larger groups should be undertaken.

Importancia del diagnóstico y tratamiento multidisciplinario del trauma periodontal por oclusión / Importance of diagnosis and multidisciplinary treatment of occlusion-induced periodontal trauma

En el presente artículo se reveen los conceptos que tratan la problemática del trauma periodontal por oclusión (TPO) desde su comienzo hasta la actualidad. Se describen las consecuencias de las fuerzas oclusales en el periodonto cuanto éste pierde la capacidad de adaptación ante las mismas o cuando éstas exceden la capacidad de adaptación del periodonto. Luego, los factores que puedenproducir un desequilibrio biomecánico en el sistema gnático necesarios para generar TPO. Por último, se propone un enfoque de tratamiento multidisciplinario para cada uno de los tipos de TPO, ilustrando cada uno de ellos con casos clínicos (AU)

Importancia del diagnóstico y tratamiento multidisciplinario del trauma periodontal por oclusión / Importance of diagnosis and multidisciplinary treatment of occlusion-induced periodontal trauma

En el presente artículo se reveen los conceptos que tratan la problemática del trauma periodontal por oclusión (TPO) desde su comienzo hasta la actualidad. Se describen las consecuencias de las fuerzas oclusales en el periodonto cuanto éste pierde la capacidad de adaptación ante las mismas o cuando éstas exceden la capacidad de adaptación del periodonto. Luego, los factores que puedenproducir un desequilibrio biomecánico en el sistema gnático necesarios para generar TPO. Por último, se propone un enfoque de tratamiento multidisciplinario para cada uno de los tipos de TPO, ilustrando cada uno de ellos con casos clínicos

Incidence of noncarious cervical lesions and their relation to the presence of wear facets.

PROBLEM: Noncarious cervical lesions are characterized by loss of tooth structure in the cervical area, compromising its integrity and resulting in esthetic problems for the patient. PURPOSE: The purpose of this study was to assess noncarious cervical lesions in young patients in an attempt to establish a possible relationship to the presence of wear facets. MATERIALS AND METHODS: First-year dental students of Bauru Dental School were studied to verify the prevalence of noncarious cervical lesions and their relationship to the presence of wear facets. After 3 years, the students were examined again to verify the incidence of new lesions, trying to establish a correlation to the previous existence of wear facets. RESULTS: Of the 1,131 teeth analyzed, 129 had noncarious cervical lesions. Twenty-nine of the 40 students had at least one tooth with one lesion. After 3 years, the incidence of new lesions was 57. Mandibular first molars (22.3%), mandibular first premolars (13.2%), mandibular second premolars (13.2%), and maxillary first molars (12.4%) showed the highest prevalence of lesions. On final analysis, 86.8% of all teeth presenting lesions showed wear facets. The identification of new lesions associated with the presence of wear facets identified during the first exam 3 years earlier was statistically significant (p < 0.01). CONCLUSIONS: The patterns of wear facets found in the study population examined were associated with an increased occurrence of noncarious cervical lesions. CLINICAL SIGNIFICANCE: Occlusal factors, especially the presence of wear facets, should be considered in the management of noncarious cervical lesions.

[A study of calcitonin gene-related peptide-immunoreactive nerve fibers of rat molar pulp during traumatic occlusion and after removal].

OBJECTIVE: To study the effect of traumatic occlusion on CGRP-immunoreactive (CGRP-IR) nerve fibres in rat molar pulp and observe the recovery of CGRP-IR nerve fibres after removal of traumatic occlusion. METHODS: To observe immunohistochemically the change of CGRP-IR nerve fibres in molar pulp during traumatic occlusion and after removal. RESULTS: The increase of number, density and morphology of CGRP-IR nerve fibres in traumatic occlusion group was more than in control group, however, the changes of CGRP-IR nerve fibres in removal of traumatic occlusion group were less than in control group. CONCLUSIONS: The changes of CGRP-IR nerve fibres in number, morphology, and density are induced by traumatic occlusion in rat molar pulp, however, the nerve fibres recover to normal by removal of traumatic occlusion.

Histological study of rat masseter muscle following experimental occlusal alteration.

It has been suggested that occlusal interference results in masticatory muscle dysfunction. In our previous study, occlusal interference reduced the rat masseter energy level during masticatory movements. The purpose of this study was to investigate the histological alterations of rat masseter muscles following experimental occlusal alteration with unilateral bite-raising. A total of eight male adult Wistar rats were equally divided into control and experimental groups. The experimental rats wore bite-raising splints on the unilateral upper molar. However, 4 weeks after the operation, the anterior deep masseter muscles were removed and then stained for succinic acid dehydrogenase (SDH), haematoxylin eosin (HE) and myofibrillar ATPase. Most of the muscle fibres in experimental rats remained intact, although partial histological changes were observed, such as extended connective tissue, appearance of inflammatory cells in the muscle fibres and existence of muscle fibres with central nuclei and central cores. Moreover, the fibre area-fibre frequency histograms of experimental muscle indicated a broad pattern than that of controls. These results indicated that occlusal interference caused histological changes in masseter muscles and that this may be related to the fact that the masseter energy level was reduced during masticatory movements in unilateral bite-raised rats.