Lingual Aspect Research Articles

Comparative Evaluation of Two Final Irrigation Techniques for the Removal of Precipitate Formed by the Interaction between Sodium Hypochlorite and Chlorhexidine.

To evaluate the effectiveness of two final irrigation techniques for the removal of precipitate formed by the interaction between sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Sixty freshly extracted human maxillary incisor teeth were taken and randomly divided into three groups, containing 20 teeth each. Group 1 (control group), were irrigated with 5 ml of 2.5% NaOCl and a final flush with 5 ml of 2% chlorhexidine. Group 2 were irrigated with 5 ml of 2.5% NaOCl and 5 ml of 2% chlorhexidine followed by 5 ml of saline and agitated with F-files. Group 3 were irrigated with 5 ml of 2.5% NaOCl and 5 ml of 2% chlorhexidine followed by 5 ml of 15% citric acid and passively agitated with ultrasonics. A thin longitudinal groove was made along the buccal and lingual aspect of the root using diamond disks and split with chisel and mallet. Both halves of the split tooth will be examined under stereomicroscope. Results were tabulated and analyzed statistically using analysis of variance (ANOVA) and Mann-Whitney U test. There was a significant difference between the mean values (p < 0.05) in groups 2 and 3 compared to group 1 at each level. Passive ultrasonic irrigation is more effective than the F-file agitation technique to remove the precipitate at all three levels measured. Combination of sodium hypochlorite and chlorhexidine irrigation protocol has been practiced since from many years to achieve good results. However, it has adverse effect in the form of precipitate and which is considered to be a carcinogenic in nature, hence this precipitate should be removed.

Effect of oral prophylactic instrumentation on the surface texture of all metal restorative materials.

Introduction:In the inaccessible areas on the crown the removal of calculus and stains by hand and ultrasonic instrumentation is the method for cleaning to preserve and increase the longevity of the restoration. However, when oral prophylaxis is performed on restorative crowns, it may produce some surface alterations and may favour plaque accumulation.Statement of Problem:Many patients may have restored their teeth with artificial crowns and would come to the dental office for oral prophylaxis. If a routine oral prophylaxis is followed, its effect on the restorative materials and the plaque accumulation can be studied.Materials and Methods:A total of 15 disc shaped wax patterns were invested and casted for cast titanium (Group A) and the remaining 15 disk shaped for nickel-chromium (Group B). The obtained castings were finished and polished. All the specimens were subjected to hand and ultrasonic scaling for 15 s. Profilometer and scanning electron microscopic was used to analyze and evaluate the surface roughness. Specimens of each group were embedded on the anterior lingual aspects of the removable lower retention plates. 5 volunteers were asked to wear it in the mouth for 24 h for 7 days. After 7 days, the specimens were stained with plaque disclosing solutions and the photomicrographs were taken by the optical stereomicroscope and the plaque accumulations were assessed in percentage.Results:The difference in average surface roughness (μm) of the polished test specimens was maximum for ultrasonic scaling than hand scaling and maximum for Group A than Group B. Plaque accumulation in percentage on the treated specimens was found to be nonsignificant but, mean plaque accumulation was maximum on ultrasonic scaling surface than hand scaling and maximum for Group A than Group B. Surface roughness was found to be statistically significant after hand scaling (F = 9.377, P = 0.000) and ultrasonic scaling (F = 5.373, P = 0.0000) by Student t-test.Conclusion:The Surface roughness and plaque accumulation on the specimens were more for Group A than Group B and maximum produced by ultrasonic scaling than hand scaling.

Osteosarcoma of mandible: A case report

Introduction: Osteosarcoma is common primary malignancy of bone that arises from the mesenchymal cells. It is commonly seen in younger patients having average age of 15 years. Generally, it involves long bones with fastest growth rate. the exact etiology for this tumor remains to be unknown but in some cases it runs in families. Osteosarcoma involving the jaw bones is relatively less frequently seen. Generally, osteosarcomas have diverse radiological and histopathological appearances. case report: A 31-year-old male presented with a small asymptomatic gingival growth in the lower right posterior region for a period of 20 days. the lesion extended both on the buccal and lingual aspect of 46 and 47 regions. conclusion: the subtle and asymptomatic clinical and radiological features of this type of lesion as seen in the present case may delay early diagnosis and poor treatment outcome. the purpose of this study was to report an osteosarcoma involving the lower jaw which presented as a soft tissue mass, mimicking an inflammatory gingival lesion.

Miles to Discover in Histological Grading of Odontogenic Tumours.

Odontogenic tumours (OTs) are lesions of great interest and importance to oral pathologists and maxillofacial surgeons alike, who for several decades have studied, catalogued these lesions and developed modalities for adequate treatment [1]. Ameloblastoma is the most common and most intriguing of all odontogenic tumours. Although benign it is highly polymorphic, due to its ability to undergo various forms of metaplasia. This has given rise to variants of ameloblastoma in which the stimulus for metaplastic change is poorly understood and has been attributed to the multipotentiality of odontogenic epithelium [2]. In the indexed case, 12-year-old boy presented with the complaint of gradually increasing painless growth in lower front teeth region since 8 months. No evident extraoral swelling or asymmetry was noticed. Regional lymph nodes were not clinically palpable and there was no history of trauma to the same site. Intraoral examination revealed approximately a 2.5x4cm, non tender mucosal sessile mass on lingual aspect of anterior mandible extending from central incisor to second premolar on left side obliterating the lower labial vestibule [Table/Fig-1]. [Table/Fig-1]: Intraoral picture reveals a sessile mass on lingual aspect of anterior mandible There was a faintly palpable anterior lingual expansion. The mandibular incisors, canine and premolar of left side were found to be non vital on thermal testing. Orthopantomograph (OPG) revealed a well circumscribed unilocular radiolucency in the anterior mandible extending from 44 to 35 without cortication. Thinning of lower border of mandible was seen. Root resorption of associated teeth due to pressure was evident [Table/Fig-2]. Considering the benign nature of the lesion, its site of occurrence i.e. anterior to first molars and unilocular appearance, central giant cell granuloma was considered as provisional diagnosis and excisional biopsy was done. [Table/Fig-2]: OPG showing a well circumscribed unilocular radiolucency in the anterior mandible with thinning of lower border Histopathological sections of this case showed well encapsulated tumour mass with extensive areas of squamous differentiation and features of plexiform ameloblastoma [Table/Fig-3]. [Table/Fig-3]: Photomicrograph reveals a well encapsulated tumour mass with extensive areas of squamous differentiation mixed with plexiform pattern (H&E, 10X) Few areas showed material secretion in the tumour matrix which were suggestive of calcifying epithelial odontogenic tumour but when stained with Congo red, came out to be negative [3]. Calcifications or even multinucleated giant cells were not evident in the submitted tissue. Keratin pearl formation was not seen but individual cell keratinization and squamous differentiation were evident throughout the stroma. The tumour appeared to be in biphasic pattern where at one end the tumour cells appeared to be stretched out making the intercellular ridges prominent whereas at the other end, tumour showed squamous differentiation, loss of intercellular bridges and cohesive tumour cells arranged in thick sheets [Table/Fig-4]. Tumour cells were positive for cytokeratin whereas surrounding material was negative [Table/Fig-5]. [Table/Fig-4]: Photomicrograph reveals area of cohesive tumour cells with squamous differentiation & loss of intercellular bridges (H&E, 10X) [Table/Fig-5]: Photomicrograph shows cytokeratin positivity in tumour cells (H&E, 10X) After extensive search in literature only three odontogenic tumours which show keratinization or squamous metaplasia were found. Acanthomatous ameloblstoma exhibit squamous metaplasia of stellate reticulum with or without keratin pearl formation [4]. However, in the present case frank keratin or squamous metaplasia was not seen but only squamous differentiation and individual cell keratinization were seen. Squamous odontogenic tumour also shows squamous metaplasia [5] but in the present case tumour was not arranged in follicles as well as material secretion by tumour cells did not appear to be keratin and tumour cells were not flattened squamous or cuboidal arranged in follicles. Keratoameloblastoma is a heterogenous group of odontogenic neoplasms which exhibit keratin formation in the connective tissue stroma [6]. Such frank keratin formation was absent in the present case. The index case is not of intraosseous squamous cell carcinoma as there was no dysplasia and few areas showed frank stellate reticulum like cells. Moreover, the present case is well encapsulated tumour supporting benign nature which is in contradiction to malignancy i.e. squamous cell carcinoma.

Tensile mechanical properties of swine cortical mandibular bone.

Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction.

Preliminary study on the tongue-based forensic identification

By means of the present study we intend to analyse lingual morphological aspects and demonstrate their importance and reliability as main criteria with force of evidence in using forensic dentistry to identify a person. To that end, we conducted the examination of 270 female and male adults between 21 and 40 years old, whose tongues were photographed front and side view. The purpose of the direct examination of the tongue was to emphasize morphological features: shape, type, characteristics of the longitudinal medial septum and the related grooves, as well as the lingual apex type, all of these being preserved using the alginate moulding, which helped taking the impression of the dorsal surface through direct application (from the level of the oral commissures up to the lingual tip) and that of the lateral lingual edges up to the lingual apex level. Thus, we demonstrated that the lingual impression, next to its photographic image, may constitute secure methods for forensic dentistry identification, showing that the inspection of the tongue is a real proof of life and genetic independence, in the sense that there are no two tongues with shape and texture, since lingual morphological aspects are difficult to copy and display stability over time.

The effects of healing abutments of different size and anatomic shape placed immediately in extraction sockets on peri-implant hard and soft tissues. A pilot study in foxhound dogs.

The aim of this animal study was to compare the effects of narrow, concave-straight and wide anatomic healing abutments on changes to soft tissues and crestal bone levels around implants immediately placed into extraction sockets in foxhound dogs. Forty-eight titanium implants (Bredent Medical GMBH, Germany) of the same dimensions were placed in six foxhound dogs. They were divided into two groups (n=24): test (implants with anatomic abutment) and control (implants with concave-straight abutment). The implants were inserted randomly in the post extraction sockets of P2 , P3 , P4, and M1 bilaterally in six dogs. After eight and twelve weeks, the animals were sacrificed and samples extracted containing the implants and the surrounding soft and hard tissues. Soft tissue and crestal bone loss (CBL) were evaluated by histology and histomorphometry. All implants were clinically and histologically osseointegrated. Healing patterns were examined microscopically at eight and twelve weeks. After eight and twelve weeks, for hard tissues, the distance from the implant shoulder to the first bone-to-implant contact (IS-C) was higher for control group in the lingual aspect with statistical significance (P<0.05). For soft tissues (STL), the distance from the top of the peri-implant mucosa to the apical portion of the junction epithelium (PM-Je) was significantly less on the lingual aspect in the test group (with wider abutment) at eight and twelve weeks (P<0.05). The distance from the top of the apical portion of the junction epithelium to the first bone-to-implant contact (Je-C) was significantly higher in the test group (wider abutment) in the lingual aspect at eight and twelve weeks (P<0.05). There was no connective tissue contact with any abutment surface. Within the limitations of this animal study, anatomic healing abutments protect soft and hard tissues and reduce crestal bone resorption compared with concave-straight healing abutments.

Pyramidal lobe of the thyroid gland and the thyroglossal duct remnant: A study using human fetal sections

To investigate developmental changes in the thyroglossal duct, we observed serial sagittal sections of eight embryos (crown-rump length (CRL) 6–12mm; approximately 5–6 weeks of gestation) as well as serial horizontal or cross-sections of 70 embryos and fetuses (CRL 15–110mm; 6–15 weeks). In the sagittal sections, the thyroglossal duct was identified as a small sheet or mass of relatively large cells with vacuolization anterior, superior or inferior to the fourth pharyngeal arch artery. However, we found no continuous duct-like structure that reached the thyroid gland. Thus, previous classical schemes might have overestimated the continuity of the duct. Among cross-sections of 70 specimens, we found the thyroglossal duct remnant in only two specimens (CRL 15mm and 100mm), in contrast to the pyramidal lobe, which was seen in one-third of the specimens. The duct remnant ran downward along the lateral edge of the hyoid body to reach the anterior aspect of the thyroid cartilage. However, the connection between the pyramidal lobe and the duct remnant was interrupted by the anterior cervical muscles. Therefore, it was unlikely that the thyroglossal duct remnant would more frequently be evident in fetuses than in adults. The highly tortuous course of the duct along the lingual aspect of the hyoid body, which has been reported previously, appeared to become established near term. Descent of the thyroid gland was not evident after the CRL 20mm stage (6 weeks): the gland appeared to retain its position at the level of the third–sixth cervical vertebrae.

A longitudinal assessment of periodontal disease in 52 Miniature Schnauzers.

BackgroundPeriodontal disease (PD) is the most widespread oral disease in dogs and has been associated with serious systemic diseases. The disease is more prevalent in small breeds compared to large breeds and incidence increases with advancing age. In prevalence studies 84% of beagles over the age of 3 and 100% of poodles over the age of 4 were diagnosed with PD. Current knowledge of the rate of progression of PD is limited. The objective of this study was to determine the rate of PD progression in miniature schnauzers, an at risk small breed of dog.Dogs (n = 52, age 1.3-6.9 years) who had received a regular oral care regime prior to this study were assessed for levels of gingivitis and periodontitis around the whole gingival margin in every tooth under general anaesthetic. Assessments were conducted approximately every six weeks for up to 60 weeks following the cessation of the oral care regime.ResultsAll of the 2155 teeth assessed entered the study with some level of gingivitis. 23 teeth entered the study with periodontitis, observed across 12 dogs aged between 1.3 and 6.9 years. 35 dogs had at least 12 teeth progress to periodontitis within 60 weeks. Of the teeth that progressed to periodontitis, 54% were incisors. The lingual aspect of the incisors was significantly more likely to be affected (p < 0.001). The severity of gingivitis in periodontitis-affected teeth was variable with 24% of the aspects affected having very mild gingivitis, 36% mild gingivitis and 40% moderate gingivitis. Periodontitis progression rate was significantly faster in older dogs. Only one dog (age 3.5) did not have any teeth progress to periodontitis after 60 weeks.ConclusionsThis is the first study to have assessed the progression rate of periodontitis in miniature schnauzers and highlights that with no oral care regime, the early stages of periodontitis develop rapidly in this breed. An oral care regime and twice yearly veterinary dental health checks should be provided from an early age for this breed and other breeds with similar periodontitis incidence rates.

Submental intubation in oral maxillofacial surgery

Background: Oral and maxillofacial surgical procedures present a unique set of problems for both the anaesthesists and the surgeons. Simultaneous access to the oral or nasal cavities and dental occlusion is required for the surgical treatment of some craniofacial deformities. Generally, airway is maintained by orotracheal or nasotracheal intubation and some instances by tracheostomy however, nasotracheal intubation is contraindicated in skull base or midface fracture. Tracheostomy has inherent complications ranging from surgical emphysema to disfiguration where as orotracheal route prevents free access to oral cavity. In these circumstances, submento-tracheal intubation may provide a better option to overcome these problems.&#x0D; Objective: The aim of this study was to evaluate outcome of conversion of orotracheal route to submentotracheal route for surgical correction of maxillofacial trauma &amp; deformity and time required to change from oral to submental route, accidental extubation, postoperative complications, and the healing of intraoral and submental scars were evaluated.&#x0D; Patients and Methods:&#x0D; Method: A total of 23 patients were selected from maxillofacial department of BSMMU and other institutions from December 2007 to March 2011 to use this technique. After standard orotracheal intubation, a 2 cm incision was made lateral to the midline in the submentum and a blunt dissection opposite to the skin incision on the lingual aspect of the mandible provides access to the floor of the mouth, the orotracheal tube is disconnected and pulled through the floor of the mouth then to the submental incision, the tube is then sutured to the skin. Surgery was completed without interference from flexometallic endotracheal tube. Following surgery the sequence is reversed and the patients extubated in the conventional manner.&#x0D; Results The technique was used in 13 patients with multiple facial fractures &amp; 10 patients with facial deformity. The mean age of the group was 30 (20-50) years .The submental orotracheal intubation was completed successfully in all patients. No accidental extubations or tube injuries occurred. The mean time required for intubation was 6 minutes. All patients were extubated in the operating theatre. The intraoral and submental accesses healed with minimal scarring in all patients .There were no incidence of intra- or postoperative complications related to submental intubation.&#x0D; Conclusions Submental intubation is a simple, safe, and predictable approach without significant morbidity that facilated safe airway and enhances meticulous surgical procedure of fractured skull base and midface.&#x0D; JBSA 2012; 25(1): 21-27

Effects of coronal substrates and water storage on the microhardness of a resin cement used for luting ceramic crowns.

Composite resin and metallic posts are the materials most employed for reconstruction of teeth presenting partial or total destruction of crowns. Resin-based cements have been widely used for cementation of ceramic crowns. The success of cementation depends on the achievement of adequate cement curing.ObjectivesTo evaluate the microhardness of Variolink® II (Ivoclar Vivadent, Schaan, Liechtenstein), used for cementing ceramic crowns onto three different coronal substrate preparations (dentin, metal, and composite resin), after 7 days and 3 months of water storage. The evaluation was performed along the cement line in the cervical, medium and occlusal thirds on the buccal and lingual aspects, and on the occlusal surface. Material and MethodsThirty molars were distributed in three groups (N=10) according to the type of coronal substrate: Group D- the prepared surfaces were kept in dentin; Groups M (metal) and R (resin)- the crowns were sectioned at the level of the cementoenamel junction and restored with metallic cast posts or resin build-up cores, respectively. The crowns were fabricated in ceramic IPS e.max® Press (Ivoclar Vivadent, Schaan, Liechtenstein) and luted with Variolink II. After 7 days of water storage, 5 specimens of each group were sectioned in buccolingual direction for microhardness measurements. The other specimens (N=5) were kept stored in deionized water at 37ºC for three months, followed by sectioning and microhardness measurements. ResultsData were first analyzed by three-way ANOVA that did not reveal significant differences between thirds and occlusal surface (p=0.231). Two-way ANOVA showed significant effect of substrates (p<0.001) and the Tukey test revealed that microhardness was significantly lower when crowns were cemented on resin cores and tested after 7 days of water storage (p=0.007). ConclusionThe type of material employed for coronal reconstruction of preparations for prosthetic purposes may influence the cement properties.

CT Scan Investigation for an Unusual Presentation of Talon Cusp in Fused Mandibular Permanent Tooth

Background: Talon cusp is a rare anomaly projecting from the dento-enamel junction to a variable distance towards the incisal edge of an anterior tooth. Hyperactivity of the enamel organ during morphodifferentiation has been accredited to its formation. When it occurs, the effects are mainly aesthetic and functional and so early detection and treatment is essential in its management to avoid complications. Case presentation: An unusual case of talon cusp on the lingual aspect of a mandibular central incisor with fusion is reported. Conclusion: The management and treatment outcome of talon cusp depends on the size, presenting complications and patient cooperation.

New perspectives in the treatment of severe mandibular atrophy: “double sandwich” osteotomy

b o g r r a m fi the crestal periosteum, becomes the roof of the defect, and the second (lingual aspect), which remains attached to the he gold standard for treatment of advanced mandibular trophy continues to be autologous bone grafting. 1,2 Since ts description in the 1970s, the sandwich technique has een found to be reliable for the reconstruction of atrophic andibles (Cawood and Howell types IV-V). 1,3–5 Its main dvantages are the potential for three-dimensional recontruction, minimal morbidity, and stable long-term outcomes. ,3–5 However, beyond certain cranialisation of the cut fragent of bone, the vertical vector becomes mixed and the econstructed alveolar ridge may be morphologically inadeuate for the placement of implants.

The adaptive significance of enamel loss in the mandibular incisors of cercopithecine primates (Mammalia: Cercopithecidae): a finite element modelling study.

In several primate groups enamel is reduced or absent from the lingual (tongue) side of the mandibular incisor crowns akin to other placental and marsupial mammalian groups such as rodents, lagomorphs and wombats. Here we investigate the presumed adaptation of crowns with unilateral enamel to the incision of tough foods in cercopithecines, an Old World monkey subfamily, using a simulation approach. We developed and validated a finite element model of the lower central incisor of the rhesus macaque (Macaca mulatta) with labial enamel only to compute three-dimensional displacements and maximum principal stresses on the crown subjected to compressive loads varying in orientation. Moreover, we developed a model of a macaque incisor with enamel present on both labial and lingual aspects, thus resembling the ancestral condition found in the sister taxon, the leaf-eating colobines. The results showed that, concomitant with experimental results, the cercopithecine crown with unilateral enamel bends predominantly towards the inside of the mouth, while displacements decreased when both labial and lingual enamel are present. Importantly, the cercopithecine incisor crown experienced lower maximum principal stress on the lingual side compared to the incisor with enamel on the lingual and labial aspects under non-axial loads directed either towards the inside or outside of the mouth. These findings suggest that cercopithecine mandibular incisors are adapted to a wide range of ingestive behaviours compared to colobines. We conclude that the evolutionary loss of lingual enamel in cercopithecines has conferred a safeguard against crown failure under a loading regime assumed for the ingestion (peeling, scraping) of tough-skinned fruits.

The thickness of alveolar bone at the mandibular canine and premolar teeth in normal occlusion.

The purpose of this study was to investigate the alveolar bone thickness on the buccal and lingual aspects of mandibular canines and premolars using cone-beam computed tomography (CBCT). The differences between the left side and the right side and that in male and female measurements were reviewed. Three-dimensional CBCT of 20 subjects with normal occlusion (9 males and 11 females; mean [SD] age, 21.9 [3.0] y) were used. The thickness of the buccal and lingual bone walls, perpendicular to the long axis of the root, was evaluated at 3 and 5 mm apical to the cementoenamel junction (CEJ) and at the root apex. The mean buccal bone thickness measured at 3 and 5 mm apical to the CEJ was less than 2 mm on the canines and the premolars. The buccal bone thickness of the second premolar at 3 and 5 mm from the CEJ was significantly greater than that of the canine and the first premolar. There were no significant differences between the left and right sides, and the overall measurements of the alveolar bone thickness did not show significant male/female differences. This study presented the thickness of the buccal and lingual bone in different locations apical to the CEJ in subjects with normal occlusion and the frequency distribution of thick buccal bone wall (≥ 2 mm). The second premolar had the highest frequency distribution of thick buccal bone (≥ 2 mm) when compared with canine and the first premolar. The teeth with thin buccal bone (< 2 mm) should be treated with care for the implant because a thin buccal bone may be damaged more easily and buccal bone resorption may occur. This study may provide estimated value for patients with normal occlusion during tooth extraction and implant installation in the canine and premolar area of the mandible. Preoperative radiographic analysis, with care in using CBCT, may be applied for tooth extraction and implant therapy.

Laser light passage through restored and carious posterior teeth.

Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty-two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio-bucco-lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one-third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF.

Can cone beam CT predict the hardness of interradicular cortical bone?

ObjectivesOrthodontic mini implants can be inserted at the interradicular site. The bone quality at this site may affect the stability and anchorage of the implant. Bone density is clinically evaluated by Hounsfield units (HU) obtained from cone beam CT (CBCT). The objective of this study was to determine the correlations between HU, microhardness and cortical bone thickness of interradicular site at various segments (anterior/posterior) and aspects (buccal/lingual) of both jaws in a swine model.Materials and methodsEight mandible and maxilla swine bones were scanned by CBCT. The HU and thickness of the above-mentioned sites were determined. Then, a Knoop microhardness test was applied and the Knoop Hardness Number was obtained (KHN).ResultsThe mandible parameters spread over a wider range than the maxilla. The buccal aspect of the maxilla had higher HU and KHN values than the mandible. The lingual aspect of the mandible had higher KHN values than the maxilla. Posterior segments had higher HU and KHN values. The thickness of the alveolar cortical bone was greater in the maxilla than in the mandible. Correlations were found between HU and KHN for 3 of the 4 sites (anterior or posterior, buccal or lingual) of the mandible only. No correlations were found for the maxilla. Upon pooling the HU and KHN data for the whole jaw, correlation was found for the maxilla as well.ConclusionsRelying on HU values as a predictor of cortical bone hardness should be considered with caution.

Effect of Mandibular Tori on Glottic Exposure During Simulated Suspension Microlaryngoscopy

Mandibular tori have been identified as a contributing factor in difficult exposure during intubation. However, no investigation has measured the effect of mandibular tori on glottic exposure during suspension microlaryngoscopy (SML). The objective of this study was to measure how the size and location of mandibular tori affect glottic exposure during simulated SML at different thyromental distances. Suspension microlaryngoscopy was modeled on an anatomically accurate skull and larynx with thyromental distances between 6 and 12 cm. Mandibular tori were simulated by protruding screws 5 to 15 mm from the lingual aspect of the mandible. The tori were positioned either 15 mm (anterior) or 25 mm (posterior) from the midline of the symphysis. The glottic exposure for the various-size tori in each location was measured by recording the displacement of the glottiscope tip relative to the most anterior exposure achievable without tori. The glottiscope angle relative to the horizontal plane was measured for each condition. Mandibular tori of more than 10 mm had a significant impact on glottic exposure. Displacement of the glottiscope tip ranged from 2 to 9 mm for anteriorly placed tori and from 7 to 29 mm for posteriorly placed tori, with larger tori causing greater displacement. Increasing the thyromental distance increased the posterior glottiscope tip displacement regardless of torus size or location. The glottiscope angle increased with larger tori (12º to 28º), but this angle did not change with increasing thyromental distance. Larger size and more-posterior location of mandibular tori more significantly reduce glottic exposure during SML. The inner table of the mandible is the most relevant anatomic constraint on glottic exposure, which varies with the presence or absence of mandibular tori independent of thyromental distance.

Morphometric characteristics of cortical and trabecular bone in atrophic edentulous mandibles

Adaptations of the alveolar ridge after tooth loss have been well described. However, studies on the morphometric characteristics of cortical bone are rare; hence, this study of human atrophic edentulous mandibles was undertaken. Total cortical area, porosity, and thickness, and the percentage of cortical area in the complete mandibular area as well as in an area (height, 10 mm) starting at the most caudal point of the trabecular compartment and extending in the coronal direction were determined in 185 thin ground sections of edentulous mandibles (incisor region, 49; premolar region, 76; molar region, 60; 95 from females and 90 from males; mean age, 78.2 years, SD ± 7.8 years; Caucasian donors; cause of death: cardiovascular disease). Further, mandibular height and width and degree of residual ridge resorption (RRR) were recorded. The percentage of cortical area in the complete mandibular area increased with increasing RRR. Yet, evaluation of the 10-mm caudal portion corresponding to the basal part of the mandibular body did not confirm these changes in cortical bone. Cortical porosity and thickness decreased from the mesial to the distal region. Cortical porosity was unaffected by RRR, while cortical thickness increased, mainly at lingual aspects. In conclusion, cortical bone remained stable in different degrees of RRR except for some modulations in the lingual aspects. Changes in the relative composition between cortical and trabecular bone are due to loss of height and total area, mainly at expense of trabecular bone area, but not to adaptations of the cortical bone.

High-Grade Osteoblastic Osteosarcoma of The Mandible: Case Report

Osteosarcoma is the most common bone malignancy and accounts for 20% of all sarcomas, but rarely affects the jaws. Young man, 16, came to the CDO-FOUSP complaining of a swollen face. Clinical examination showed a deformed hemiface and enlarged buccal and lingual cortical aspect of the mandibular right side. Incisional biopsy revealed a mesenchymal neoplasm. The case was referred to HCFMUSP for investigation and management. Imaging revealed an extensive osteolytic lesion with cortical destruction in the angle of the jaw. Hemimandibulectomy and microsurgical flap reconstruction were done. Histopathological examination of the specimen confirmed the diagnosis of high-grade osteoblastic osteosarcoma. The patient completed the cycle of adjuvant chemotherapy and 6 months of follow-up. Osteosarcomas have varied clinical and histopathological findings. Early surgical resection of the lesion is necessary to avoid recurrent and metastatic complications of the tumor.