Margin Of Palate Research Articles

Accuracy of merging scans of definitive fixed prosthodontic impressions to obtain single, accurate digitized master casts.

Many elastomeric impressions sent to commercial laboratory dental technicians may include marginal defects. To fabricate accurate restorations, digital technology may be used to merge digital files of defective impressions into a single standard tessellation language (STL) file free of errors. This would save clinicians and patients time and may improve clinical care. The purpose of this study was to compare the accuracy of digital master casts reconstructed from merged STL files of defective impressions with the file of the original defect-free preparations. Ivorine teeth on a dentoform were prepared to receive a posterior fixed dental prosthesis (FDP) with complete coverage preparations. An impression was made in a stock tray using polyvinyl siloxane (PVS) impression material and an extraoral scanner (E3, 3Shape, Denmark) was used to digitize the impression; this was the reference cast. Wax was used to create defects on the buccal and lingual margins of the preparations. Fifteen PVS impressions were made of the FDP preparations with defects in the mesial and distal margins; another set of 15 PVS impressions was made of FDP preparations with defects in the buccal and palatal margins for a total of 30 impressions. All impressions were digitized using the same extraoral scanner (E3, 3Shape, Denmark). Corresponding STL files were paired and merged, and a master cast was created by eliminating the defects using the scanned data. This master cast was compared to the reference cast using reverse engineering software (Geomagic, Morrisville, NC, USA). The results were expressed as average errors and standard deviations in the master casts relative to the reference cast. To account for the presence of positive and negative values in the data set, in terms of errors, the root mean square (RMS) value was calculated for each sample. The mean average error in the sample was -0.4 μm. The average upper limit of 95% confidence interval was +36.5 μm, while the average lower limit of 95% confidence interval was -37.3 μm. The mean RMS of the errors found was 18.9 μm. The results of this study indicated that merging digitized definitive impressions to correct marginal defects resulted in master casts with a high level of accuracy relative to the reference cast.

Does Resin Cement Type and Cement Preheating Influence the Marginal and Internal Fit of Lithium Disilicate Single Crowns?

This paper assesses the effect of cement type and cement preheating on the marginal and internal fit of lithium disilicate single crown. Methods: 40 maxillary premolars were selected, restored with lithium disilicate single crowns. Teeth were randomly assigned into four groups (n = 10) based on cement type (Panavia SA or LinkForce) and preheating temperature (25 °C or 54 °C). After fabrication of the restoration, cements were incubated at 25 °C or 54 °C for 24 h, and each crown was cemented to its corresponding tooth. After 24 h, all specimens were thermally aged to (10,000 thermal cycles between 5 °C and 55 °C), then load cycled for 240,000 cycles. Each specimen was then sectioned in bucco-palatal direction and inspected under a stereomicroscope at x45 magnification for marginal and internal fit evaluation. The data were statistically analyzed (significance at p ≤ 0.05 level). Results: At the mid-buccal finish line, mid-buccal wall, palatal cusp, mid-palatal wall, mid-palatal finish line, and palatal margin measuring points, there was a significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 25 °C and the group cemented with LinkForce at 25 °C, while there was no significant difference (p > 0.05) at the other points. At all measuring points, except at the palatal cusp tip (p = 0.948) and palatal margin (p = 0.103), there was a statistically significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 54 °C and the group cemented with LinkForce at 54 °C. Regardless of cement preheating, statistically significant differences were found in the buccal cusp tip, central groove, palatal cusp tip, and mid-palatal wall (p ≤ 0.05) in the lithium disilicate group cemented with Panavia SA at 25 °C and 54 °C, as well as the mid-palatal chamfer finish line and palatal margin in the LinkForce group cemented with Panavia SA at 25 °C and 54 °C. At the other measurement points, however, there was no significant difference (p > 0.05). Conclusions: The type of resin cement affects the internal and marginal fit of lithium disilicate crowns. At most measuring points, the cement preheating does not improve the internal and marginal fit of all lithium disilicate crowns.

Clinical Pathologic Conference Case 1: An ulcerated nodular mass on the right hard palate

A 30-year-old Hispanic male presented to an oral surgeon with a 2.5 cm × 1 cm ulcerated nodular mass on the right lateral hard palate (Figure 1). The mass extended from the lateral palatal margin to the midline and antero-posteriorly from the rugae to the distal aspect of tooth #2. The surface was ulcerated and covered by a yellow fibrinous exudate focally with a violaceous erythematous pigmentation in other areas. The mass had raised borders and was painful and tender to palpation. As per the patient, the mass was present for a month, and he thought he had burnt the roof of his mouth after consumption of pizza.

DIAGNOSTIC CHALLENGES OF ORAL LESIONS IN A PATIENT AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION

Oncohematologic patients after hematopoietic stem cell transplantation (HSCT) are at risk of developing opportunistic oral infections and malignant neoplasms. The objective of this report is to describe 3 diagnostic challenges of oral lesions that affected the same posttransplant patient: an atypical herpes simplex virus lesion in ventral tongue, a gingival actinomycosis infection, and later a leukemic infiltration on the soft palate. A 57-year-old female patient first complained of a progressive and painful sublingual nodule for 3 days at D+35 of HSCT by extranodal natural killer/T-cell lymphoma, and final diagnoses were atypical herpes simplex virus 1 and 2 infection. Two months later, ulcerated lesions in the vestibular and palatal gingival margin of the left upper molars were noted, with final diagnosis of Actinomyces sp infection. Fifteen days later, an erythematous lesion with necrotic center was observed in the soft palate, and the diagnosis was palatal infiltration by extranodal natural killer/T-cell lymphoma.

Surgical procedures performed to improve the prosthetic prognosis in case of maxillary defects: A review of the literature

Aim The purpose of this review is to address the surgical procedures that need to be followed to obtain a maxillary defect that can be suitable to receive a prosthesis. Methods An extensive search of the literature was performed, on the databases of PubMed/Medline and Scopus, in addition to congress proceedings and books, written in English or Italian. Literature search was performed using combinations of the following keywords: (“obturator prognosis” OR “palatal obturator” OR “obturator prosthesis” OR “prosthetic prognosis”) AND (“maxillectomy” OR “maxillary defect”). Results 35 articles, 2 books and 3 congress proceedings were included. After the study of the records included in this review, it was found that surgeon must preserve the anterior maxilla as much as possible, because it is the most suitable site for the placement of implants. Furthermore, if the implant site is involved in post-operative radiotherapy, it is advisable to know the x-ray dose of such an exposition. The surgical cut should preserve mucosa and bone support around the tooth adjacent to the defect, and keratinized mucosa should cover the palatal margin of the defect Equally important is to prepare an adequate access to the defect, because the turbinates and the bands of oral mucosa may prevent the prosthesis from engaging key areas of the defect, impairing function. Conclusion A complete knowledge about the construction techniques and biological/mechanical principles of maxillofacial prosthesis is essential to perform surgical interventions that enhance the prosthetic prognosis.

Satisfaction with shortening the palatal extension of a mouthguard for water polo players: A randomized crossover study.

Approximately 50% of water polo players have suffered orofacial injuries. However, fewer than 8% of players wear a mouthguard. A more comfortable mouthguard design is therefore needed to increase compliance. The aim of this study was to assess the effect of reducing the palatal extension of a custom-made mouthguard on the degree of satisfaction with a mouthguard among water polo players. Eighteen elite water polo players participated in this randomized crossover trial. Two custom-made mouthguards were fabricated for each participant using 4-mm-thick ethyl vinyl acetate foils, defined by the extension of the palatal margin from the cervical line: conventional (6mm) and shortened (2mm). The mouthguards were worn during all training sessions and matches, in a randomized sequence (one mouthguard type for the first and fourth weeks and the other for the second and third weeks). Mouthguards were evaluated on 10-point scales for discomfort, interference with oral functions, protection, and general satisfaction after each training session or match. Players evaluated the shortened mouthguard as having less interference with speech (Effect 1.30; P<0.001), breathing (Effect 0.98; P=0.004), swallowing (Effect 1.30; P<0.001), and athletic performance (Effect 0.61; P=0.03) compared with the conventional mouthguard. The perceived degree of protection was similar among participants when wearing each type of mouthguard. Overall, players were more satisfied with the shortened mouthguard (Effect 0.64; P=0.03). Reducing the palatal extension of a custom-made mouthguard from 6 to 2mm improves the overall satisfaction of elite water polo players without affecting the perceived degree of protection.

Imaging measurement and clinical significance of occipitocervical angle in healthy people at different ages

To measure imaging data of occipitocervical angle in healthy people at different ages by X-ray. One hundred and fifty asymptomatic volunteers(75 males and 75 females) aged from 20 and 70 years old with an average of(44.83±13.88) years old were divided into 5 groups according to different ages(20 to 29 years old, 30 to 39 years old, 40 to 49 years old, 50 to 59 years old and 60 to 70 years old), and 30 people in each group. All people underwent lateral radiography of neck on neutral position. McGregor line (the lowest connection line between upper margin of hard palate and occipital scales of plating), occipitocervical angle(OCA) formed by edge of C2 vertebral body, takami's occipitocervical angle formed between connection line of posterior marginal of C2 vertebral body and parallel lines of hard palate were collected. The data were performed statistical analysis according to gender and different ages, and analyzed correlation between OCA and TOCA. OCA of 75 males at different ages were (14.71±3.09)° and(14.22±4.27)° in 75 females. TOCA of 75 males at different ages were (90.50±4.63)° and (90.57±6.67) ° in 75 females. There were no statistical difference in OCA and TOCA in people at different ages(P<0.05). There were no significant meaning among 5 groups at different ages in OCA and TOCA(P>0.05). The relation analysis results showed positive correlation between OCA and TOCA(r=0.454, P<0.01). The paper provided normal values for occipitocervical angle in population of southwestern China between 20 and 70 years old, and results may be useful for posterior occipitocervical fixation and fusion.

A New Species of Anoura Gray, 1838 (Chiroptera: Phyllostomidae) from Peru, with Taxonomic and Biogeographic Comments on Species of the Anoura caudifer Complex

Anoura is a Neotropical genus of long-tongued bats containing at least 10 species, whose taxonomy has been revised substantially in recent years. Herein, we describe a new species of Anoura from the Cordillera Oriental of the Peruvian Andes, inhabiting montane forests (Yungas) at 1900–3450 m altitude, along the Rio Cosnipata valley in Manu Biosphere Reserve, Cuzco; where it is sympatric with A. peruana, A. cultrata, and A. caudifer. This new species is most similar to A. caudifer and A. aequatoris, but it is distinguished from them by a unique combination of morphological characters: pelage dark; uropatagium narrow with margins densely furred; foot claws whitish; skull with a long and narrow rostrum; zygomatic arches complete and straight (in lateral view); posterolateral margins of palate without processes; braincase smoothly rounded; first upper premolar (P2) peg-like and separated from the upper canine by a wide gap; second upper premolar (P3) without anterobasal cusp; mandible long, straight, thin and delicate with a large symphysis. Principal Component Analysis separated well the new species from A. aequatoris and A. caudifer. In MANOVA analyses, followed by Bonferroni post-hoc test, the new species differed significantly from A. aequatoris and A. caudifer in six and 11 characters, respectively. The new species and A. aequatoris have montane distributions, whereas A. caudifer occurs at lower elevations. In Peru, the new species and A. aequatoris show disjunct distributions: the former in the central and southern regions, and the latter in the north-central region of the country. This suggests a vicariant effect probably related to the deep Rio Apurimac. Finally, we comment on the taxonomy of the A. caudifer complex, discuss the biogeographical implications of the discovery of the new species, and suggest the recognition of a new region of endemism for small mammals in the southern Yungas, south of the Rio Apurimac to Bolivia.

Influence of mouthguards and their palatal design on the stress-state of tooth-periodontal ligament-bone complex under static loading.

The mouthguard (MG) is an effective device to reduce the risk of dental traumatic injuries, but the mechanical effects of wearing a MG and its design are not fully understood. The aim of this study was to evaluate the mechanical influence of wearing a MG and its palatal design on the tooth-periodontal ligament-bone complex (TPBC) by computational analysis using the finite element method. Three-dimensional subject-specific geometry of the TPBC was reconstructed from medical computed tomography (CT) images. Two patterns of MG geometries were constructed which covered the palatal domain or not (the position of these palatal margins was set at -8mm (pattern 1) and 4mm (pattern 2) from the cervical line. Five cases of static mechanical analysis were conducted by changing the location of the loading points from near the cervical line to the tip of the tooth. Wearing a MG decreased strain concentration around the loading point and cervical domain regardless of the MG palatal design. Elastic energy in the periodontal ligament (PDL) and tooth (including enamel and dentin) decreased when the MG was worn, whereas the MG palatal design slightly affected the degree of reduction in the elastic energies. The location of the loading points remarkably affected the elastic energy in the TPBC components and the extent of its reduction due to the MG. These findings indicated that the protection ability of the MG exerted in the restricted situations of traumatic events occurs regardless of the MG design.

A redescription of the Long-tailed Nesokia, Nesokia bunnii, and designation of a neotype (Rodentia: Muridae).

Long-tailed Nesokia, Nesokia bunnii, is a large rat restricted to the Mesopotamian marshes in Basra Province in southern Iraq. The species is known from five museum vouchers collected between March 1974 and January 1977. The type and the paratype, deposited in the Natural History Research Centre and Museum, University of Baghdad, Iraq, were destroyed during War on Iraq in 2003. By studying morphological details on three museum specimens in the Senckenberg Institution, Frankfurt a. M., Germany, we show that N. bunnii is unique among the Bandicoot rats (Nesokia and Bandicota) in having (1) rufous dorsal pelage, (2) facial mask of rufous, dark brown, grey and whitish areas, (3) whitish belly which is clearly demarcated along flanks, (4) ventral hairs white to bases, (5) woolly underfur, (6) long front claws, and (7) large tail annulation. Similar to N. indica, but in contrast to Bandicota, N. bunnii displays short incisive foramina, posterior margin of hard palate which terminates at the level of the third molar, and robust, hypsodont and laminate molars which lack posterior cingula. To objectively define the taxon we designate a neotype, which was collected at Saraifa, 30 km north of Qurna, Iraq. Our study highlights the importance of museum collections in documenting biodiversity and the indifference of decision makers and international institutions regarding their safe future.

Compliance of dental laboratory technicians with dentists’ instructions for fabrication of a PFM crown

Abstract Objectives The aim of this study was to evaluate the compliance of dental technicians from different dental laboratories with dentists’ written prescriptions during fabrication of porcelain-fused-to-metal (PFM) crowns. Materials & methods Final impressions for a prepared Ivorine tooth no. 21 were sent to 16 dental laboratories (8 government and 8 commercial) for fabrication of a PFM crown. A detailed, standard work authorization form accompanied each case, including a request to fabricate a uniform-thickness metal framework, with incisal translucency, hypocalcification-like stain, porcelain facial shoulder and metal palatal chamfer margins with palatal occlusion in porcelain. All crowns were then collected, and data were recorded and analyzed statistically with Fisher’s Exact and Pearson’s Chi-square tests by means of SPSS and WinPepi software. Results No statistically significant differences were found between laboratory groups in following the instructions for metal substructure thickness ( P > 0.6), facial and palatal margins ( P = 1.0) or the dimensions of the hypocalcification-like stain ( P = 0.28). However, commercial labs were significantly better than government labs in the location criteria for hypocalcification and incisal translucency ( P = 0.04). When the total numbers of successfully followed criteria were compared, commercial labs were found to be significantly better than government labs in following the written instructions ( P = 0.002). Conclusion Although a standard work authorization form was used, commercial labs performed better than government labs, especially in esthetic characterizations such as hypocalcification-like staining and incisal translucency.

Transpalatal advancement pharyngoplasty and expansion sphincterplasty for obstructive sleep apnea

Uvulopalatopharyngoplasty (UPPP) has been the most commonly performed procedure for obstructive sleep apnea. However, high failure rates of this procedure, which can reach 50%-70% of the cases, have led to various modifications in the UPPP technique to address persistent obstruction after traditional UPPP surgery. Expansion sphincteroplasty was developed as a modification of UPPP to address lateral wall collapse proximal to the free margin of the palate and transpalatal advancement pharyngoplasty was developed as a modification of UPPP to address more proximal anterior posterior narrowing of the retropalatal segment. Transpalatal advancement has also been shown to address proximal lateral wall airway narrowing.

The effects of ferrule configuration on the anti-fracture ability of fiber post-restored teeth

ObjectivesTo evaluate the fracture resistance of fibre post-restored teeth with various ferrule configurations by using fracture failure tests and extended finite element analysis (XFEM). Methods60 Maxillary central incisors were collected and divided into six groups (n=10) according to various ferrule configurations with different ferrule heights in the labial or palatal region. All of the teeth were endodontically treated and restored by using fibre posts, composite cores and metal crowns. Fracture failure tests were performed on the post retained restorations until fracture occurred. The ultimate load was recorded and analyzed by one way analysis of variance (ANOVA). The fractured specimens were longitudinal sectioned and investigated by micro-stereomicroscope and scanning electronic microscope. XFEM was used to model the fracture of the post-restored teeth and exhibit crack initiation and propagation in the cement layers. ResultsFracture failure tests indicated that the palatal ferrule significantly enhanced the fracture resistance of the post-restored teeth, regardless the height of the labial ferrule. The fractography investigation exhibited that the crack initiated at the palatal margin of the cement layer and propagated to the cervical region of the root. XFEM confirmed these findings and demonstrated that increasing of the palatal ferrule could effectively enhance the anti-fracture ability of the adhesive cement and protected the integrity of adhesive cement. ConclusionAdhesive interface was the susceptible structure of the post retained restorations. Increasing palatal ferrule height could effectively reduce the stress concentrated within the palatal adhesive cement. Clinical Significance“Ferrule effect” exhibits the protection of the interity of cement layer. Increasing the ferrule height, especially in the palatal side, can significantly enhance the anti-fracture ability of fibre post-restored teeth.

Effect of thickness of zirconia-ceramic crown frameworks on strength and fracture pattern

The aim of the present study was to evaluate the fracture load and fracture mode of thin Ceria-stabilized tetragonal zirconia polycrystals/Al(2)O(3 )nanocomposites (Ce-TZP/A) and Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) crown frameworks. Artificial maxillary second premolars were prepared for metal-ceramic crown and all-ceramic crown restorations and Co-Cr tooth analogs were duplicated. 10 standard (0.5 mm overall thickness) zirconia-ceramic crown frameworks (Y-TZPs) for all-ceramic crown preparation and 10 modified (a 0.3-mm-thick framework increased in thickness by adding a 1.0-mm-thick palatal margin with a height of 2.0 mm) zirconia-ceramic crown frameworks (Y-TZPm, Ce-TZP/Am) for metal-ceramic crown preparation were fabricated. The frameworks were cemented to the Co-Cr tooth analog and loaded vertically until fracture. The fracture load of Y-TZPs (180.0 N) and Ce-TZP/Am (183.7 N) were significantly higher than that of Y-TZPm (133.7 N). There was a significant difference in fracture mode between Y-TZPm and Ce-TZP/Am. Within the limitation of this study, Ce-TZP/Am provide sufficient strength for clinical application.

Evaluation of fiber post-supported restorations under simulated occlusal loading

There is a lack of information comparing the effect of a rigid versus flexible post on the marginal seal of post-and-core supported crowns subjected to long-term repeated loading. The purpose of this study was to examine the leakage pattern of complete coverage restorations retained with either a metal or fiber-reinforced resin post under simulated occlusal loads. Thirty-six maxillary central incisors were endodontically treated and provided with a post-and-core supported crown. One group was restored with a fiber-post (EasyPost Lux) and another was restored with a metal post (Parapost) (n=12). Both groups were loaded for 120,000 cycles to 70 N while immersed in a dye solution. A control group (n=12), similarly restored with a fiber post but not loaded, was also included. All teeth were transversely sectioned serially from the tooth-core interface towards the apex. Digital photographs were made to determine the extent of leakage on the buccal, mesial, palatal, and distal aspects along the depth of the post. A nonparametric Kruskal-Wallis test was used to determine any difference between groups (α=.05). Dye penetration occurred in all stress-cycled specimens and was more extensive on the palatal than other aspects. The fiber-post group cyclically stressed to 70 N showed a significantly greater amount of leakage than the control or the Parapost group (P<.05). In in vitro testing, the rigidity of the post influenced the seal of post-and-core-supported crowns at the palatal margin.

The effect of wearing custom‐made mouthguards on the aeroacoustic properties of Japanese sibilant /s/

There have been many reports on the discomfort of speech when wearing oral appliances. Fricatives articulated in an oral cavity can be difficult to pronounce when oral appliances are worn, because the oral cavity is partially changed by their installation. Sibilant /s/, one fricative, is especially difficult to pronounce when wearing oral appliances. This study investigates the effect of the difference in the setting positions of the palatal margin of custom-made mouthguards on the aeroacoustic characteristics of sibilant /s/. Eighteen subjects (11 women and seven men) participated. The palatal margin of mouthguards was set at the gingival line for nine subjects and 4 mm from the line for another nine subjects. Acoustical analyses examined the difference of the palatal margins of the mouthguards on the autocorrelation coefficient, the zero crossing count, and the spectral peaks of sibilant /s/. The results showed that the zero crossing count of the waveforms and the spectral peaks of sibilant /s/ were significantly broadened and shifted toward the low-frequency range with the mouthguard whose palatal margin extended 4 mm from the gingival line than the mouthguard whose palatal margin was set at the gingival line. We believe that a more appropriate palatal mouthguard design for custom-made mouthguards can be made by considering the aeroacoustical effects. Our study supported the mouthguard whose palatal margin was set at the gingival line by considering the influence on pronouncing sibilant /s/. We believe that a more appropriate palatal mouthguard design for custom-made mouthguards can be made based on the balance of aeroacoustical effects and mechanical requirements.

NiTi Expansion in Operated Unilateral Cleft Palate Patients

Objective: To evaluate the efficacy of nickel-titanium expander for maxillary expansion and the skeletal and dental changes associated with the expander in operated cleft palate patients. Materials and methods: Ten male unilateral cleft lip and palate patients in the age group of 9 to 13 years with transverse maxillary deficiency and with no history of bone grafting procedure, were selected from the patients visiting the combined cleft lip and palate clinic/orthodontic clinic. Results: Orthopedic expansion of maxillary segments ranged from 2 to 5 mm, constituted 25% of total expansion. Maxillary Intermolar width measured at cuspal tips and palatal gingival margins (T-16, 26 and G-16, 26) increased by a mean of 8.6 mm (p < 0 .001) and 5.4 mm (p < 0 .001). Maxillary Inter premolar width measured at cuspal tips and palatal gingival margins (T-14, 24 and G-14, 24) increased by a mean of 5.6 mm (p < 0.001) and 4.7 mm (p < 0 .001). Maxillary intercanine width measured at cuspal tips and palatal gingival margins (T-13, 23 and G-13, 23) increased by a mean of 4.3 mm (p < 0.01) and 3.38 mm (p < 0.01). Postexpansion changes measured on the mandibular dental casts showed insignificant changes except in the intermolar area. Mandibular intermolar width measured at cuspal tips and lingual gingival margins (T-36, 46 and G-36, 46) increased by a mean of 0.6 mm (p < 0.05). The dental expansion constituted for 75% total expansion. Mandibular, occlusal plane angles increased by 2 to 3° resulting in increased TAFH. Conclusion: NiTi expansion in operated cleft patients, showed mainly orthodontic expansion. The significant change in the maxillary intermolar region is due to the direct placement of NiTi palatal expander to 16, 26.

Intra Oral Epithelial Bands in a New Born: Report of Two Cases and Review of Literature

Intra oral epithelial bands is a very rarely reported condition. It is sometimes associated with cleft lip and palate [1, 2]. Stenberg et al. suggested that these connective tissue bands stretch between the mandible and the maxilla [3]. Miskynyar reported that congenital adhesion occurs between maxilla and mandible (syngnathism) or between tongue and palatal margins (glossopalatal ankylosis) and he states that adhesions consist of membranous band of epithelium which is supported by connective tissue, muscles or bone [4]. Congenital fusion of jaws is also a very rare condition which may be unilateral or bilateral, and may or may not be associated with syndromes. In the long standing cases, temporomandibular joint ankylosis can occur [5]. Only 17 cases of intra oral bands were found by Spivack and Bennett [6] until 1968 reported as palatoglossal ankylosis in the literature. Laster et al. in 2001 [7] reported only 24 documented cases of congenital maxillo-mandibular fusion. We at our centre Acharya Vinoba Bhave Rural Hospital Sawangi, Wardha, Maharashtra, India operated 1,134 cases (Table 1) of cleft patients from February 2007 to July 2010, out of which 664 were males and 470 females. Out of which only two patients presented with synechiae and syngnathia associated with cleft palate. The syndromic patients were 710, the most common syndrome associated was Pierre Robins Sequence. Table 1

Nonlinear visco-elastic finite element analysis of porcelain veneers: a submodelling approach to strain and stress distributions in adhesive and resin cement.

To assess under load the biomechanical behavior of the cementing system of feldspathic vs alumina porcelain veneers. A 3D model of a maxillary central incisor, the periodontal ligament (PDL) and the alveolar bone was generated. Incisors restored with alumina and feldspathic porcelain veneers were compared to a natural sound tooth. Enamel, cementum, cancellous and cortical bone were considered isotropic elastic materials; conversely, dentin was designated as orthotropic. The nonlinear visco-elatic behavior of the PDL was considered. The adhesive layers were modelled using spring elements. A 50-N load at a 60-degree angle to the tooth's longitudinal axis was applied and validated. Stress concentration in the interfacial volumes of the main models was identified and submodelled in a new environment. Regarding tooth structure, strain concentrations were observed in the root dentin below the CEJ. As to the cement layer, tensile stresses concentrated in the palatal margin of the adhesive complex. Despite the effects on tooth deformation, the rigidity of the veneer did not affect the stress distributions in the cement layer or in the adhesive layers. In both cases, the palatal and cervical margins seemed to be the most stressed areas.

Sound spectral analysis of snoring sound and site of obstruction in obstructive sleep apnea syndrome

Conclusion: This study demonstrates that there is a significant difference in sound spectrum between first snoring sound after upper level and lower level obstructive apneas, and it is possible to use sound spectrum analysis as a supplementary method to determine the obstructive site of a patient with obstructive sleep apnea syndrome (OSAS). Objectives: To investigate the difference in sound spectrum between the first snoring sounds after upper level (above the free margin of soft palate) obstructive apneas and lower level (below the free margin of soft palate) obstructive apneas in patients with OSAS. Methods: Thirty male patients with OSAS were included in this study. Overnight snoring sound was recorded and continuous upper airway pressure measurement was performed simultaneously on each subject. The first snores after upper level and lower level obstructive apneas were identified and analyzed acoustically. Results: The mean of peak frequencies, central frequencies, and proportions of energy from 800 Hz to 2000 Hz and above 2000 Hz of the first snoring sounds after lower level obstructive apneas were higher and the proportion of energy below 800 Hz was lower than those after upper level obstructive apneas. The differences of all the parameters were of significance. The power spectrum of the two types of snoring sounds also exhibited different characters.