Oro-facial function and quality of life in children and adolescents with large horizontal maxillary overjet-A case-control study.

BACKGROUND: Large horizontal maxillary overjet (overjet) is associated with reduced bite force (BF) and number of contacts, which influence the chewing effectivity (CE). Oral health, oro-facial function (OF) and malocclusion have great impact on psychological well-being and quality of life (QoL). OBJECTIVES: The aims of the study were to examine OF, temporomandibular disorders (TMD), BF, CE, QoL and well-being in children and adolescents with large overjet. METHODS: The study was a case-control study including healthy children with large overjet in the study group compared to a control group of healthy children with neutral occlusion, all 9-14 years old. OF was examined by use of Nordic Orofacial Test-Screening (NOT-S), Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and registration of morphological and functional occlusion. QoL and well-being were examined using KIDSCREEN-10 and Strengths and Difficulties Questionnaire. RESULTS: The study and control groups included 37 and 32 participants, respectively. Significantly increased NOT-S score (p < .001) and reduced BF (p = .011), numbers of contacts (p < .001) and CE (p = .005) were found in the study group. BF, numbers of contacts and CE were negatively associated with erupting canines and premolars. No significant difference was found in age, gender, dental eruption, TMD diagnosis or QoL between the groups. Significantly increased emotional symptoms (p = .007), hyperactivity (p = .043) and total difficulties score (p = .009) were found in the study group. CONCLUSION: The study group showed higher NOT-S score and reduced BF, number of contacts and CE. No difference in QoL were found between the groups, although reduced well-being and increased emotional symptoms, hyperactivity and total difficulties were found in the study group.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study.

OBJECTIVE: To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT). METHODS: This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes. RESULTS: After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05). CONCLUSIONS: MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Safety and Efficacy of a New Synthetic Material Based on Monetite, Silica Gel, PS-Wallastonite, and a Hydroxyapatite Calcium Deficient: A Randomized Comparative Clinic Trial.

Background and Objectives: Maxillary bone defects related to post-extraction alveolar ridge resorption are usual. These defects may lead to failure in further surgical implant phases given the lack of bone volume to perform the dental implant. The objective of this clinical assay was to evaluate the safety and efficacy of an experimental synthetic bone substitute in the preservation of post-extraction maxillary alveoli. Materials and Methods: 33 voluntary patients who had at least one maxillary premolar tooth that was a candidate for exodontia (n = 39) and subsequent implant rehabilitation participated. The regenerated alveoli were monitored by means of periodic clinical examinations (days 9 ± 1, 21 ± 4, 42 ± 6, and 84 ± 6), measuring the height and width of the alveolar crest (days 0 and 180 ± 5), measurement of radiodensity using tomographic techniques (days 0-5 and 175 ± 5), and histological examination of biopsies collected at 180 ± 5 days. Results: No significant differences were observed during the entire follow-up period between the two groups with respect to the safety variables studied. A variation in width of -0.9 ± 1.3 mm and -0.6 ± 1.5 mm, and a variation in height of -0.1 ± 0.9 mm and -0.3 ± 0.7 mm was observed for experimental material Sil-Oss® and Bio-Oss®, respectively. The radiodensity of the alveoli regenerated with the experimental material was significantly lower than that corresponding to Bio-Oss®. However, the histological study showed greater osteoid matrix and replacement of the material with newformed bone in the implanted beds with the experimental material. Conclusions: Both materials can be used safely and proved equally effective in maintaining alveolar flange dimensions, they are also histologically biocompatible, bioactive and osteoconductive. The experimental material showed the advantage of being resorbable and replaced with newformed bone, in addition to promoting bone regeneration.

Alveolar bone changes after rapid maxillary expansion with tooth-born appliances: a systematic review.

Background: During rapid maxillary expansion (RME), heavy forces are transmitted to the maxilla by the anchored teeth causing buccal inclination and buccal bone loss of posterior teeth. Objective: To systematically review the literature in order to investigate whether RME causes periodontal sequelae, assessed by cone-beam computed tomography (CBCT). Search methods: Fifteen electronic databases and reference lists of studies were searched up to March 2017. Selection criteria: To be included in the systematic review, articles must be human studies on growing subjects, with transversal maxillary deficiency treated with RME and with assessment of buccal bone loss by CBCT images. Only randomized and non-randomized trials were included. Data collection and analysis: Two authors independently performed study selection, data extraction, and risk of bias assessment. Study characteristics (study design, sample size, age, sex, skeletal maturity, type of appliance, daily activation, evaluated linear measurements, observation period, CBCT settings), and study outcomes (loss of buccal bone thickness and marginal bone) were reported according to the PRISMA statement. Results: On the basis of the applied inclusion criteria, only six articles, three randomized clinical trials and three controlled clinical trials were included. An individual analysis of the selected articles was undertaken. The risks of bias of the six trials were scored as medium to low. Limitations: The results of the present systematic review are based on a limited number of studies and only one study included a control group. Conclusions and implications: In all considered studies, significant loss of buccal bone thickness and marginal bone level were observed in anchored teeth, following RME. Further prospective studies correlating the radiological data of bone loss to the periodontal soft tissues reaction after RME are required. A preliminary evaluation of the patient-related risk factors for RR may be advisable when considering to administering RME. Registration: This systematic review was registered in the National Institute of Health Research database with an appropriate protocol number (http://www.crd.york.ac.uk/PROSPERO Protocol: CRD42017062645). Funding: The present study has not received any contributions from private or public funding agencies.

Maxillary length in euploid and aneuploid fetuses.

PURPOSE: To examine the maxillary length of euploid and aneuploid fetuses in the second and third trimester. METHODS: Retrospective study utilizing stored 2D images of second and third trimester fetal profiles obtained at the University of Tuebingen, Germany. The length of the maxilla was measured as a straight line between the anterior ventral and posterior ventral edges of the maxilla. RESULTS: The study population consisted of 347 euploid fetuses and 122, 36, 5, 8, and 4 fetuses with trisomy 21, 18, and 13, Turner syndrome, and triploidy. In the euploid and aneuploid group, mean gestational age was 22.3 and 22.7 weeks, respectively. The maxilla length in euploid fetuses was significantly dependent on gestational age and it was significantly shorter in fetuses with trisomy 21, 18, and 13, and triploidy but not in those with Turner syndrome. In 75.4 and 14.8%, and 11 fetuses with trisomy 21, the maxilla was below the mean, the 5th and 1st centile of the euploid population. CONCLUSIONS: In fetuses with trisomy 21, 18, and 13 and triploidy, the maxilla is significantly shorter, but the difference is only settled, so that it is unlikely that the maxilla length will play a role in second and third screening for aneuploidy.

Measurement of forces and moments around the maxillary arch for treatment of a simulated lingual incisor and high canine malocclusion using straight and mushroom archwires in fixed lingual appliances.

INTRODUCTION: An Orthodontic SIMulator (OSIM) was used to investigate the propagation of forces and moments around a simulated archform for a gingival displaced canine and lingual displaced lateral incisor using fixed lingual orthodontic appliances. METHODS: In-Ovation L self-ligating lingual brackets were bonded to anatomically shaped teeth on the OSIM, and the teeth were positioned such that a G4 NiTi 0.016" large maxillary mushroom archwire could be ligated in passive position. Each trial consisted of two movements: a 3mm lingual displacement of the 1-2 lateral incisor at 0.2 mm increments, and a 1.5 mm gingival displacement of the 2-3 canine at 0.15 mm increments (n = 50). Anterior brackets were repositioned to accommodate G4 NiTi 0.016" universal straight archwires (n = 50). Tests were completed at 37°C, and force and moment data in all directions was collected for each tooth around the arch at all increments. RESULTS: In general, the straight archwire produced significantly larger forces and moments at the centre of resistance for teeth of interest than did mushroom archwires. Specifically, the straight archwire produced 2.62 N and 3.81 N more force in the direction of tooth movement on the tooth being moved for a gingival displaced canine and lingual displaced lateral incisor, respectively, as compared to mushroom archwires. CONCLUSIONS: Results from this study suggest that mushroom archwires may provide better mechanics for movement of teeth in the anterior segment when using a round archwire; however, only biomechanical data was considered in this study and there are many factors that need to be considered in treatment planning.

Orthodontically induced cervical root resorption in humans is associated with the amount of tooth movement.

INTRODUCTION: The aim of this study was to investigate the variation in the amount of the orthodontically induced cervical root resorption and the association with several factors, such as the amount of tooth displacement, location of tooth in the maxilla or mandible, and presence of an interference that may influence the amount of root resorption. SUBJECTS AND METHODS: This study included 30 subjects (20 females, 10 males) with an age range of 11.3 to 43.0 years. Using a standardized experimental orthodontic tooth movement, 59 premolars were moved buccaly during 8 weeks with application of 1 N force. Fifty-eight contralateral premolars not subjected to orthodontic tooth movement served as controls. At the end of the experimental period the teeth were carefully extracted, scanned in a micro-computed tomography scanner with a resolution of 9 µm, and the reconstructed images were processed for volumetric evaluation of resorption craters at the cervical part of the root surface. Data were analyzed using unpaired t-test and the Pearson's correlation. RESULTS: Higher amount of cervical root resorption was detected in the orthodontically moved teeth (0.00055 mm3) compared to controls (0.00003 mm3; P < 0.001). Moderate correlation was found between root resorption in the two experimental teeth within the same individual (R = 0.421, P = 0.023). Teeth located in the mandible presented more resorption than those in the maxilla (P = 0.046). The amount of root resorption was correlated to the amount of tooth movement (R = 0.318, P = 0.016). CONCLUSION: Application of a 1 N force over a 2-month period provokes severe root resorption at the compression cervical sites. Resorption is correlated with the amount of tooth movement and the location of the teeth.

Fetal alcohol spectrum disorders and assessment of maxillary and mandibular arc measurements.

Fetal alcohol spectrum disorders (FASD) comprise a range of physical differences and neurologic deficits from prenatal alcohol exposure. Previous studies suggest that relative maxillary growth deficiency can accompany FASD. Using the Fetal Alcohol Syndrome Epidemiologic Research (FASER) database, we investigated how maxillary and mandibular arcs and the ratio between them differ between FASD and non-FASD individuals. First, we established normative values for maxillary and mandibular arcs and maxillary-to-mandibular arc ratio. In our control group (545 males, 436 females), mean maxillary and mandibular arcs for males/females were 24.98/24.52 cm and 25.91/25.35 cm, respectively. The ratio was 0.9643 and 0.9676 for males and females, respectively. We then evaluated the effect of microcephaly, short stature, and low weight (<10th centile), individually on arcs in controls. Generally, arcs were reduced significantly but the ratio did not differ. We compared our controls to 138 male and 135 female FASD cases. We noted a significant difference in arcs in male and female groups, but not the ratio. We compared non-FAS controls with reduced growth parameters to similar cases with FASD. We did not find a significant difference in arc or ratio measurements. Therefore, we conclude the effect of prenatal alcohol exposure on maxillary and mandibular arc measurements is primarily on overall facial growth and less on asymmetric growth of the maxilla relative to the mandible, at least using this technique. © 2016 Wiley Periodicals, Inc.

Evaluation of the injection pain with the use of DentalVibe injection system during supraperiosteal anaesthesia in children: a randomised clinical trial.

PURPOSE: The purpose of this study was to compare the use of a traditional syringe (TS) and the DentalVibe (DV) Injection Comfort System on the pain of needle insertion and injection of supraperiosteal (SP) anaesthesia into the mandibles and maxillas of children aged 6-12 years. METHODS: The study was a randomised, controlled, crossover clinical trial, comprising 60 children requiring an operative procedure with SP anaesthesia on both their mandibular and maxillary molars, bilaterally. One of the molars was treated with a TS, and the contralateral tooth was treated with the DV for both arches. On each visit, subjective and objective pain was evaluated using the Wong-Baker FACES Pain Rating Scale and the Face, Leg, Activity, Cry, Consolability Scale. Patients were asked which technique they preferred. The data were analysed using Wilcoxon signed-rank test, Spearman's correlation test, and Mann-Whitney U-test. RESULTS: No statistically significant differences were noted between TS and DV for pain during injection and needle insertion for supraperiosteal anaesthesia in either the maxillary and mandibular operative procedures. CONCLUSIONS: Children experienced similar pain during SP anaesthesia administered with a TS and the DV, regardless of gender and jaw differences. DV was less preferred over the traditional procedure in children.

Slow and fast orthodontic tooth movement: an experimental study on humans.

INTRODUCTION: The aim of this study was to investigate the variation in the amount of the orthodontically induced tooth movement in humans and potential associations between the amount of tooth movement with age and location in the mandible or maxilla. SUBJECTS AND METHODS: This study included 11 participants (7 females, 4 males) with an age range of 11.3-28.6 years. In a standardized experimental orthodontic tooth movement protocol, two premolars of each participant were moved buccally during 8 weeks with the use of 1 N force. No functional or localized obstacles were affecting the displacement. Plaster models before and after the experimental tooth movement were constructed, digitized, and superimposed, to evaluate the amount of tooth movement of each tooth. Random effects linear regression analysis was performed to examine associations between tooth displacement, age, and tooth location. RESULTS: The mean displacement of the teeth was 2.7±1.4mm. The range of tooth movement varied substantially between individuals (0.6-5.8mm). The displacement of the teeth within the same individual was highly correlated (R (2) = 0.78, P < 0.001). The tooth displacement decreased with age; however, this finding did not reach statistical significance (ß = -0.11, 95% CI: -0.28, 0.05, P = 0.172). The tooth movement was higher in the maxilla than in the mandible (ß = 0.47, 95% CI: 0.81, 0.86, P = 0.018). CONCLUSION: Wide range of tooth displacement revealed slow and fast movers in this sample. Larger displacements were recorded in the maxilla compared to the mandible and in younger individuals.

Immediate loading short implants inserted on low bone quantity for the rehabilitation of the edentulous maxilla using an All-on-4 design.

More studies evaluating the outcome of short-length dental implants in immediate loading are needed. To evaluate the use of short-length tapered implants in immediate loading for complete edentulous maxillae rehabilitations using an All-on-4 design. This retrospective clinical study included a cohort of 43 patients with 172 implants (74 short-length implants) inserted in low bone quantity. The patients were followed between 4 months and 6 years (average = 3 years). Outcome measures were implant survival, marginal bone remodelling, biological and mechanical complications. Two patients with four short-length implants were lost to follow-up during the first year. Three short and three long implants failed in four patients, rendering an overall cumulative survival rate implant and patient level, respectively, of 95.7% and 95.1% for short implants, 100% for regular implants and 96.6% and 95.2% for long implants. The average marginal bone remodelling at 1 and 3 years was 0.97 and 1.25 mm for the short implants, 0.82 and 0.87 mm for regular implants and 0.87 and 0.98 mm for long implants. Three patients presented 4 short-length implants with peri-implant pockets (3 implants in 2 patients were pseudo-pockets). Mechanical complications were registered in 13 patients (7 provisional prostheses fractures and 6 abutment screw loosening). All complications were treated successfully. Within the limitations of this clinical study, the short-term outcome of fixed prosthetic complete edentulous maxillae rehabilitations supported by short-length implants inserted in low bone quantity areas is viable. Long-term clinical studies are necessary for evaluating the outcome of these implants.

Three-dimensional finite element analysis of maxillary protraction with labiolingual arches and implants.

INTRODUCTION: In this study, we aimed to evaluate the effects of maxillary protraction using traditional labiolingual arches and implant-type protraction devices before orthopedic treatment of patients with skeletal Class III malocclusion. METHODS: A 3-dimensional finite element model of the maxillofacial bones with high biologic similarity and including the sutures was constructed. Through stress and displacement calculations, a biomechanical study was performed for the maxillofacial bones, mandible, and sutures. RESULTS: We quantified detailed changes in the sutures with 2 protraction methods to analyze their effects on the growth of the maxillofacial bones. CONCLUSIONS: (1) The labiolingual arch is suitable for skeletal Class III patients with crossbite and deep overbite. The frontomaxillary and zygomaticomaxillary sutures played major roles in the forward displacement and counterclockwise rotation of the maxilla. The temporozygomatic and pterygopalatine sutures did not change significantly. (2) The implant type of protraction device is suitable for skeletal Class III patients with crossbite and open bite. Both the frontomaxillary and zygomaticomaxillary sutures played decisive roles in the forward displacement and clockwise rotation of maxilla. The temporozygomatic and pterygopalatine sutures showed small changes. (3) The labiolingual arch caused less stimulatory growth on the maxilla, whereas the implant caused greater stimulatory growth on the maxilla. Protraction with the labiolingual arch is more suitable for early skeletal Class III patients at a younger age; protraction with an implant is applicable to skeletal Class III patients in the late mixed dentition or early permanent dentition.

Occlusal rehabilitation of pseudo-class III patient.

To treat a patient with anterior crossbite, the clinician should first assess if it is a genuine class III or a pseudo-class III malocclusion. Cephalometric analysis is important; however, registering a patient's centric relation (CR) is simple, quick, and costless and can play a decisive role in a differential diagnosis for this type of patient profile. This clinical report depicts a patient clinically diagnosed as class III. After mandible manipulation in CR, it was noted that the patient in question was a pseudo-class III. The treatment was based on the pseudo-class III diagnosis. Therefore, the patient was rehabilitated by occlusal adjustments and conventional and implant-supported prostheses and without the need for invasive orthognathic surgery.

Multiple, supernumerary retained teeth in the course of cleido-cranial dysplasia. A case report.

Cleido-cranial dysplasia, often referred to as Scheuthauer-Marie-Sainton syndrome, is an autosomal dominant disorder of the musculo-skeletal system. Patients with cleido-cranial dysplasia are characterized by short stature, frequent varus or valgus hip, kyphoscoliosis, underdevelopment of the scapulas and the sternum, incorrect number of ribs. The most characteristic feature is unilateral or bilateral, partial or total underdevelopment of clavicles. Mental development is not affected in this syndrome. Malocclusion, occlusal irregularities, multiple supernumerary teeth, impacted teeth, and persistent milk teeth are found in the stomatognathic system. Teeth often have abnormal anatomy. Gothic palate, cleft hard and soft palate are diagnosed. The aim of this paper is to present a case of a 12-year-old boy diagnosed with irregularities in the masticatory system involving an additional number of retained teeth. The boy was referred by an orthodontist for surgical and orthodontic team therapy. The case presented confirms the observations of other authors that only the multi-specialty collaboration of a pediatrician, a geneticist, an orthopedist, an orthodontist, a maxillofacial surgeon, an implant prosthetic surgeon and a physiotherapist can provide proper diagnosis and treatment.

The maxillary second molar - anatomical variations (case report).

To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the individuality of treatment tactics.

Extraction sockets: erratic healing impeding factors.

AIM: The aim of this exploratory study was to analyse prevalence of extraction sockets showing erratic healing and evaluate factors potentially impeding healing. METHODS: Erratic healing was defined as extraction sites showing clinical observations of fibrous scar tissue occupying the extraction site rather than bone following 12 or more weeks of healing. Computerized tomography was used to evaluate characteristics and calculate Hounsfield unit scores for sites showing erratic healing. RESULTS: A total of 1226 dental records from Seoul National University Dental Hospital archives including patients subject to extractions prior to implant placement were evaluated. Seventy subjects (5.71%) and 97 sites (4.24%) exhibited erratic extraction socket healing. Maxillary incisor/canine sites showed the lowest (0.47%), whereas mandibular molar sites the highest (5.41%) occurrence. In the multivariable analysis, erratic healing was more likely to occur in subjects <60 years old (OR = 2.23, 95%CI = 1.26-3.94), subjects with hypertension (OR = 2.37, 95%CI = 1.24-4.55), in molar sites (OR = 4.91, 95%CI = 1.41-17.07), and following single tooth extractions (OR = 2.98, 95%CI = 1.36-6.53). Computerized tomography showed the highest incidence of bone loss for the buccal wall (49.3%). CONCLUSION: Erratic extraction socket healing appears a not uncommon sequel and local factors seem to be major contributors to its occurrence.

Finite element analysis of bone stress after SARPE.

PURPOSE: This study investigated stress distribution in maxillas that underwent surgically assisted palatal expansion (SARPE). MATERIALS AND METHODS: Five maxillary models were built: no osteotomy (M1), Le Fort I osteotomy with a step in the zygomaticomaxillary buttress (M2), Le Fort I osteotomy with a step in the zygomaticomaxillary buttress and the pterygomaxillary disjunction (M3), Le Fort I osteotomy without a step (M4), and Le Fort I osteotomy with pterygomaxillary disjunction and no step (M5). Displacement coherence and maximum stress (MS) analyses were used for all models. RESULTS: Areas of tension spread to the maxilla and the region between the alveolar ridge and the palate and a critical point in the median suture for M2, M3, M4, and M5. In M2 and M4, MS spread farther toward and over the pterygoid process, contrary to what was found in M3 and M5. M3 had a better performance than the other models, and the tensile stress was interrupted by the posterior osteotomy, thus avoiding possible damage to the sphenoid bone or difficulties in expanding the posterior region of the maxilla. CONCLUSIONS: The steps in the zygomaticomaxillary buttress and the pterygomaxillary disjunction seem to be important to decrease the harmful dissipation of tensions during SARPE.

Effect of the laser and light-emitting diode (LED) phototherapy on midpalatal suture bone formation after rapid maxilla expansion: a Raman spectroscopy analysis.

The aim of this study was to analyze the effect of laser or light-emitting diode (LED) phototherapy on the bone formation at the midpalatal suture after rapid maxilla expansion. Twenty young adult male rats were divided into four groups with 8 days of experimental time: group 1, no treatment; group 2, expansion; group 3, expansion and laser irradiation; and group 4, expansion and LED irradiation. In groups 3 and 4, light irradiation was in the first, third, and fifth experimental days. In all groups, the expansion was accomplished with a helicoid 0.020" stainless steel orthodontic spring. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm(2), t = 257 s, spatial average energy fluence (SAEF) of 18 J/cm(2)) or a LED (λ850 nm, 150 mW ± 10 mW, spot of 0.5 cm(2), t = 120 s, SAEF of 18 J/cm(2)) were used. The samples were analyzed by Raman spectroscopy carried out at midpalatal suture and at the cortical area close to the suture. Two Raman shifts were analyzed: ∼ 960 (phosphate hydroxyapatite) and ∼ 1,450 cm(-1) (lipids and protein). Data was submitted to statistical analysis. Significant statistical difference (p ≤ 0.05) was found in the hydroxyapatite (CHA) peaks among the expansion group and the expansion and laser or LED groups. The LED group presented higher mean peak values of CHA. No statistical differences were found between the treated groups as for collagen deposition, although LED also presented higher mean peak values. The results of this study using Raman spectral analysis indicate that laser and LED light irradiation improves deposition of CHA in the midpalatal suture after orthopedic expansion.

Masticatory efficiency in complete denture wearers with reduced dental arches--a randomised cross-over study.

One obstacle to placing artificial posterior teeth in manufacturing complete dentures is a reduction of the space between the maxilla and the mandible. Occasionally, second molar placement is not performed, as it does not affect aesthetics, phonetics or comfort. The aim of this study was to compare the masticatory efficiency between patients wearing maxillary and mandibular complete dentures with reduced dental arches (without second molars) (WSM) and with full dental arches (FDA). Twenty subjects were divided into two groups and randomly received new complete dentures. Patients in Group 1 were given dentures WSM, and those in Group 2 were given dentures with FDA. After the post-placement visits, an initial masticatory efficiency test was performed with Optocal, an artificial test food. Fifteen days later, second molars were placed in Group 1 and removed from Group 2, and a new test was performed. Comminuted material was treated and sieved under vibration. The mean and standard deviation of masticatory efficiency with FDA were 10.4 and 8.1, respectively. In the tests WSM, the mean and standard deviation were 8.4 and 3.3, respectively. After removing the second molars in Group 2 and adding them in Group 1, the mean and standard deviation were 15.7 and 14.7 for Group 1 and 12.5 and 10.4 for Group 2, respectively. Within the limitations of this study, placing artificial teeth up to the first molars can be performed when needed without compromising masticatory efficiency.

Finite element analysis of stability and functional stress with implant-supported maxillary obturator prostheses.

STATEMENT OF PROBLEM: Maxillary resections jeopardize the stability and functional stress generated by implanted-supported prostheses. PURPOSE: The purpose of this study was to evaluate the stability and functional stress caused by implanted-supported obturator prostheses in simulated maxillary resections of an edentulous maxilla corresponding to Okay Classes Ib, II, and III, with no surgical reconstruction. MATERIAL AND METHODS: Implants were positioned in the residual maxilla, and bar-clip retention systems were designed for each experimental model. The 3-dimensional models of the maxillary resection and corresponding implanted-supported obturator prosthesis, constructed from a computed tomography scan, were used to develop a finite element mesh. Loads were simultaneously applied to the occlusal (80 N) and anterior (35 N) platforms corresponding to the prosthetic teeth. Qualitative analysis was based on the scale of maximum principal stress; values obtained by means of quantitative analysis were expressed in MPa. RESULTS: The implant-supported obturator prostheses tended to rotate toward the surgical resection, the region with no osseous support. Tensile and compressive stresses in the gingival mucosa and in the cortical bone increased as the osseous support and the numbers of implants and clips diminished. CONCLUSIONS: All evaluated bar-clip retention systems displayed a tendency toward dislodgment of the obturator prosthesis, increasing as the osseous resection area amplified. The osseous tensile and compressive stresses resulting from the bar-clip retention system for Okay Classes Ib, II, and III maxillectomy may not be favorable to the survival rate of implants.