Evaluation of Long-term colour resistance of composite materials used in aligner treatments: A comparative study.

AIM: The aim of this study is to evaluate the discolouration resistance of attachments made of composites having different physical properties, filler ratios and viscosity through the simulated environment and conditions. MATERIALS AND METHODS: Seventy-two extracted human teeth were aligned to simulate upper and lower dental arches. The attachments were prepared according to the guides determined by ClearCorrect. Three different composite groups were used for attachments preparation: Aligner Connect, G-Aenial Universal Injectable, and Tetric Prime and Tetric Evoflow combination. Dental models and aligners were kept in artificial saliva throughout the experiment of 96 weeks. The aligners were also subjected to 2308 thermal cycles and insertion and removing procedures 840 times for each period of 12 weeks. Afterwards, the models were kept in coffee and red wine solutions. Colour measurements were made with Vita Easy Shade 4.0 at 12th, 24th, 48th and 96th simulated weeks. RESULTS: No significant difference in discolouration was observed during thermal cycle application of 12th and 24th week experimental periods. In the later periods, discolouration was observed in the composite materials, and G-Aenial Universal Injectable was less coloured than the other samples. The composite samples were more coloured in proportion to their residence time. The G-Aenial Universal Injectable was more affected by wine solution, and Tetric Prime and Tetric Evoflow combination were more affected by coffee solution. CONCLUSIONS: Viscosity, resin matrix content and nature of inorganic filler particles of the composite materials significantly affect the colour changing properties of them due to the long-term ageing and exposure to colouring agents.

Comparison of the soft and hard tissue effects of two different protraction mechanisms in class III patients: a randomized clinical trial.

OBJECTIVE: The objective of the present study is to test the null hypotheses that there were no significant differences for hard and soft tissue changes induced by mini maxillary protractor (MMP) and face mask and rapid maxillary expansion (FM/RME). MATERIALS AND METHODS: Thirty-two patients who met the criteria were randomly divided into two groups: 16 patients (males/females 7/9) in the MMP group and 16 patients (males/females 6/10) in the FM/RME group. The patients in both groups were instructed to wear the appliances for at least 20 h per day until a 2-mm positive overjet was achieved. Hard and soft tissue profile changes observed by MMP and FM/RME were compared using paired and Student's t tests. RESULTS: Class III malocclusion and negative overjet were improved by means of skeletal changes in conjunction with upper incisor proclination and lower incisor retroclination in both groups. Maxilla and surrounding soft tissues (SNA, Ls-E, and Ls-PMV) were significantly moved anteriorly with less rotation of the palatal plane in the MMP group. Mandibular incisors were found to be more retrusive in the FM/RME group (p = 0.024). CONCLUSION: Both groups showed similar effects except more anterior movement of the maxilla and surrounding soft tissues with less rotation of the palatal plane and retrusion of lower incisors in the MMP group. CLINICAL RELEVANCE: This is the first study to compare the soft and hard tissue changes induced by MMP appliance with a conventional FM /RME.

Effects of maxillary protraction for early correction of class III malocclusion.

This prospective study investigated the skeletal, dental, and soft-tissue effects of a mini maxillary protractor appliance in class III subjects with maxillary retrusion and mandibular protrusion and compared these changes with those of untreated, well matched control sample with normal occlusions. Twenty patients with class III malocclusion (mean age 11.1 ± 0.8 years) and 20 subjects with normal occlusion (mean age 10.9 ± 0.4 years) were included to this study. The class III subjects were treated with the mini maxillary protractor appliance, and the others were used as control subjects. Paired t-test and Student's t-test were used to determine the within- and between-group differences, respectively. In the study group, the maxilla moved forward (SNA, 2.0 degrees and A-Y, 2.4mm) (P < 0.001) with a slight rotation of palatal and occlusal planes (SN-PP, -0.8 degree and SN-OP, -0.7 degree) (P > 0.05). The mandible displaced backwards and downwards (SNB, -1.1 degrees; SND, -0.9 degree; B-Y, -0.9 mm and Pog-Y, -0.3mm; P < 0.001). These movements in the maxilla and mandible caused a significant improvement in intermaxillary sagittal relationship (ANB, 3.0 degrees; Convexity, 6.3 degrees; Wits, 4.6mm; P < 0.001). The maxillary incisors moved forward (2.2 degrees) while the mandibular ones backward (-1.9 degrees). The improvement in overjet was 5.0mm, and 66.1 per cent of this change (3.3mm) was skeletal (A-Y; 2.4mm and B-Y; -0.9 mm), and the remaining (1.7 mm) dentoalveolar (U1-NA; 0.9 mm and L1-NB; -0.8mm). The change in Ls-E measurement was more in the study group (2.1mm), and the difference between the groups was statistically significant (P < 0.001).

Effects of force magnitude on relapse: An experimental study in rabbits.

INTRODUCTION: The aims of this study were to investigate the effects of 2 force levels on the amount of relapse and to determine whether there is a relationship between the rates of tooth movement and relapse. METHODS: Approximately 20-g (group I) and 60-g (group II) forces were applied to the maxillary central incisors of 25 young adult (14 weeks of age) New Zealand female rabbits. Active tooth movement lasted 20 days. Then, the appliances were removed, and the incisors were released. The distance between the incisors was measured daily from the midlevels of the crowns by using a digital caliper during the active phase of tooth movement for 20 days, and then relapse was measured at the same level for 37 days. Analysis of variance and the Bonferroni multiple range test were used for statistical analyses. RESULTS: After active tooth movement, the mean total opening amounts were 3.98 ± 0.59 mm in group I and 4.82 ± 0.82 mm in group II, and the mean difference was approximately 0.8 mm. A rapid relapse was observed on the initial days in both groups, and its rate decreased with time. Significant relapse was observed in the first 5 and 8 days of the experiment in 20-g and 60-g force groups, respectively. The relapse in group II was significantly greater than in group I only on the first day of experiment. Statistically significant correlations were found between total tooth movement and relapse (R = 0.896, P <0.001). CONCLUSIONS: These results showed a close relationship between the amount of relapse and orthodontic force magnitude. Greater relapse occurred during the initial days after appliance removal, and this indicates that retention appliances are needed immediately after the removal of orthodontic appliances.

Effects of the functional regulator III on transversal changes: a postero-anterior cephalometric and model study.

Studies assessing the transversal treatment changes caused by the functional regulator III (FR-3) are limited in number. This clinical study was planned to analyse the transversal effects of the FR-3 appliance therapy. The treatment group consisted of 17 patients (8 males and 9 females) with Class III malocclusion, who were treated with the FR-3 appliance. The control group consisted of 17 subjects (7 males and 10 females) with a normal occlusion. Mean ages of the subjects were 10.73 and 10.66 years in the treatment and control groups, respectively. Postero-anterior radiographs and stone casts were obtained before (T1) and after (T2) treatment/observation. The results of the Student's t-test comparing initial values showed that maxillary dentoalveolar and skeletal widths are significantly larger in the control group than those in the treatment group. At the end of the treatment, significant transverse increments occurred only at the dentoalveolar level of the maxilla. The transversal changes in the mandible were not statistically significant. Buccal shields of FR-3 did not stimulate the growth of maxillary apical base but caused an enhanced and supplementary widening of maxillary dental and alveolar structures.

Investigation of transmigrated and impacted maxillary and mandibular canine teeth in an orthodontic patient population.

PURPOSE: The objectives of the present study were to determine the frequency and gender difference of transmigrated and impacted canines and to evaluate the characteristics and treatment protocols in a Turkish orthodontic patient population. MATERIALS AND METHODS: We designed a retrospective study composed of pretreatment and post-treatment dental casts, intraoral photographs, and full mouth periapical and panoramic radiographs of 2,215 patients (1,275 females and 940 males). Observations were made regarding impacted mandibular and maxillary canines, retained deciduous canines, patient gender and age, side and number of transmigrated canines and associated pathologic features, and treatment of the impacted canines and transmigrated canines. The Pearson chi(2) test and Fisher's exact test were used to determine the potential differences in the distribution of canine impaction and transmigration when stratified by gender. RESULTS: The frequency of patients with impacted and transmigrated canines was 5.1% and 0.3%, respectively. None of the patients with a transmigrated mandibular canine had any pathologic changes; however, the maxillary transmigrated canine was associated with impacted mesiodens. All transmigrated canines were unilateral and impacted. Four canines migrated from the left to right, and 2 migrated from right to left. Of 6 patients, 2 had retained primary canines and 4 had exfoliated primary canines. Three of the transmigrated mandibular canines were type 1 and 2 were type 2. In the treatment protocol, 4 impacted mandibular canines and 78 maxillary canines were surgically exposed for orthodontic treatment, 4 of 6 transmigrated canines were surgically removed, and 2 were observed periodically. CONCLUSIONS: If the diagnosis of canine impaction and transmigration in patients is made earlier, it is possible that the tooth might have been in a better position for orthodontic eruption into the arch. Careful patient selection and preparation are therefore essential, as is cooperation between the orthodontist and oral surgeon.

Intermaxillary tooth size discrepancies among different malocclusion groups.

The aims of this study were to identify possible gender-related differences in tooth size ratios, to determine whether there is a prevalence for intermaxillary tooth size discrepancies in any malocclusion group, and to detect the percentage of tooth size discrepancies outside 1 or 2 standard deviations (SDs) from Bolton's mean. The material comprised the models of 500 subjects (284 females and 216 male aged between 12 and 28 years). Five groups were formed: normal occlusion, Class I, Class II division 1, Class II division 2, and Class III, which had an equal number of subjects. Tooth size measurements were undertaken using an electronic measuring device. Overall, anterior, and posterior ratios were computed as described by Bolton. For statistical evaluation, analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests were used. A significant gender difference was found only for posterior ratio in all groups (P < 0.01). There was no significant difference among the malocclusion groups in anterior ratio, but the differences for overall and posterior ratios were significant (P < 0.05 and P < 0.001, respectively). A large number of subjects had discrepancies greater than 2 SD from Bolton's mean. In addition, the means and SDs in this investigation were found to be larger than those of Bolton. Intermaxillary tooth size ratios may vary in different malocclusion types and may, to some degree, contribute to the severity of a malocclusion.

Effects of force magnitude on tooth movement: an experimental study in rabbits.

The aim of the present study was to investigate the effects of two different force levels on the amount of total and daily tooth movement in rabbits and to determine whether any increase in tooth movement is equal to the increase in force. Forces of approximately 20 (group I) and 60 (group II) g (19.6 and 58.8 cN) were applied to the upper central incisors of 25 young adult (14 weeks of age) New Zealand female rabbits. The distance between the incisors was measured daily from the mid-levels of the crowns using a digital calliper for 20 days. Analysis of variance and Bonferroni multiple range test were used for statistical analyses. The distance between the teeth in group II was significantly greater than that in group I during the first 3 days. Between days 4 and 14, no significant difference was observed. During the last 6 days, except for day 19, tooth movement in group II again increased, resulting in the distance between the teeth being greater in group II. The mean total opening was 3.98 +/- 0.59 mm in group I and 4.82 +/- 0.82 mm in group II, and the mean difference was approximately 0.8 mm. The results of this study show that there was a close relationship between tooth movement and force magnitude. However, higher forces did not produce force-equal tooth movements.

Effects of the functional regulator III on profile changes in subjects with maxillary deficiency.

The aim of this study was to determine the hard and soft tissue profile changes in Class III malocclusion subjects following functional regulator III (FR-3) treatment. The material comprised the cephalometric films of 15 patients (11 males and four females; mean ages 10.22 and 10.44 years, respectively) with a Class III malocclusion and a concave profile treated with the FR-3, and a control group of 15 subjects (11 males and four females; mean ages 10.39 and 10.27 years, respectively) with a Class I malocclusion matched for chronological age and observation period with the study group. Fourteen linear and seven angular measurements were measured on the cephalometric films taken before (T1) and after (T2) treatment/observation. The results of the Student's t-test showed that the treatment group had a concave facial profile when compared with the controls. At the end of treatment, the maxilla and surrounding soft tissues showed significant anterior movement (P < 0.001 and P < 0.01, respectively), whereas mandibular growth was restricted. The vertical dimensions increased, the upper incisors proclined, and the lower incisors retroclined significantly (P < 0.001). The FR-3 appliance produced significant improvements in the hard and soft tissues of Class III subjects with a concave profile.

Soft tissue profile changes following maxillary protraction in Class III subjects.

SUMMARY: The dentoskeletal effects of maxillary protraction (MP) therapy have been extensively investigated, while those relating to soft tissue profile changes are limited. Thus, the aim of this study was to determine the degree of soft tissue profile changes following MP therapy. The material consisted of the cephalometric films of 24 female subjects (12.69 +/- 1.08 years) with a Class III malocclusion who underwent MP therapy; these were compared with a control group of 15 females (12.13 +/- 0.63 years) with a Class I occlusion and matched for chronological age and observation period. Cephalometric films were available for all subjects before (T1) and after (T2) treatment/observation. The initial measurements and treatment/control changes were compared between the groups by means of a Student's t-test. The subjects in the MP group had a concave facial profile when compared with the controls. Comparison of the changes induced by MP therapy showed that the maxilla and surrounding soft tissues showed significant anterior movement (P < 0.001), whereas the mandible and surrounding soft tissues showed a backward and downward rotation. The improvement in facial profile predominantly resulted from maxillary soft tissue changes and mandibular hard tissue changes. The concave soft tissue profiles of the Class III subjects were corrected by anterior movement of the maxilla and a concomitant increase in the fullness of the upper lip. The concave skeletal profiles were, however, corrected mainly by backward and downward rotation of the mandible.

Prevalence and characteristics of supernumerary teeth in a non-syndrome Turkish population: associated pathologies and proposed treatment.

OBJECTIVE: The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth and evaluate the associated pathologies and treatment protocol in a Turkish patient population. STUDY DESIGN: A retrospective study was performed using full-mouth periapical and panoramic radiographs of 3491 patients (2146 females and 1345 males) ranging in age from 12 to 25. For each patient with supernumerary teeth we recorded the demographic variables (including age, sex), number, location, position, type, and morphology of supernumerary teeth, associated pathologies or complications, and whether any treatment has been carried out. The Pearson chi-squared test was used to determine potential differences in the distribution of supernumerary teeth when stratified by gender. RESULTS: Supernumerary teeth were detected in 42 subjects (1.2%), of which 27 were males and 15 were females with a 1.8:1 male female ratio (p<0.001). The most commonly found supernumerary teeth were mesiodens (31.3%) followed by premolar (25.0%), lateral (22.9%), distomolar (14.5%), paramolar (4.2%), and canine (2.1%). Of the 48 supernumerary teeth examined, 50.0% (n=24) were conical, 81.3% (n=39) were in a vertical position, and 20.8% (n=10) were erupted. Supernumerary teeth caused rotation or displacement of the adjacent teeth in 14 cases, and the impaction of the permanent teeth in 8 cases. CONCLUSION: The prevalence of supernumerary teeth in our series was found to be 1.2%, the most frequent type being mesiodens. Rotation or displacement of permanent teeth was the most frequent complication caused by supernumerary teeth.

Effects of rapid-slow maxillary expansion on the dentofacial structures.

BACKGROUND: To date, no study has determined if rapid followed by slow maxillary expansion (also termed 'semi-rapid' expansion) has the same effects on the dentofacial skeleton as rapid maxillary expansion. OBJECTIVE: To determine the vertical and sagittal changes in the facial skeleton during and following rapid then slow maxillary expansion (R-SME). METHODS: Bonded maxillary expansion appliances were used to separate the maxillae over six days by activating the midline screws twice a day. The screws were then activated three times a week until sufficient expansion was obtained (Mean: 3.4 months) and used as retainers for six months. Cephalometric measurements at the start of expansion (T1), end of expansion (T2) and end of retention (T3) were compared with paired t-tests. Pearson correlation coefficients were used to determine the associations between the expansion (dental and skeletal) and the cephalometric changes. RESULTS: The maxillae moved forward a small, but statistically significant, extent during expansion. The upper molars were extruded and the mandible 'rotated' downward and backward. Although the vertical height of the facial skeleton (SN/GoMe, S-Go, N-Me, ANS-Me) increased significantly during expansion, the changes were small and highly variable. Some dimensions (SN/GoMe) relapsed during retention, while others (S-Go, N-Me) increased. CONCLUSIONS: Rapid then slow maxillary expansion caused a small, but statistically significant, forward movement of the upper facial skeleton, a small downward and backward rotation of the mandible and a small increase in face height. The changes were similar to those found during rapid maxillary expansion.

McNamara norms for Turkish adolescents with balanced faces and normal occlusion.

BACKGROUND: There are no norms for the McNamara analysis for Turkish adolescents. OBJECTIVE: To obtain cephalometric standards for the McNamara analysis for Turkish adolescents with balanced faces and Class I occlusions, and to compare the standards with published data. METHODS: The cephalometric radiographs of 116 children (83 female, 33 male) between 11 and 16 years of age with Turkish grandparents and Class I occlusion, well-aligned upper and lower dental arches, no anterior and/or posterior crossbites and normal dentofacial structures were used. The eight linear and two angular measurements in the McNamara analysis were measured on images of the scanned radiographs. Measurements of the male and female subjects were compared with each other and with published norms for North American adolescents and adults. RESULTS: The Co-Gn, Co-A, ANS-Me and Ui-A were larger in the male subjects. Comparisons between the present study and McNamara's original study revealed that Anatolian Turkish adolescents, particularly girls, have smaller midfacial and mandibular lengths and longer and more retrusive faces than North American adolescents and adults. CONCLUSIONS: The small, but statistically significant, gender differences in mandibular and midfacial lengths and lower anterior face height may not be clinically significant. A single set of Turkish norms for the McNamara analysis may be appropriate.

Third-molar agenesis among patients from the East Anatolian Region of Turkey.

AIM: The aim of this study was to determine the frequency and distribution of third-molar agenesis in orthodontic patients from the East Anatolian Region of Turkey. METHODS AND MATERIALS: Our data were obtained from the panoramic radiographs of the 2,579 patients 12 to 16 years of age in the Department of Orthodontics at the Atatürk University in Erzurum, Turkey. Subjects with congenital deformities, such as a cleft palate, were excluded from the study. Statistical analysis was performed using SPSS software and a chi-squared test. RESULTS: Of the 2,579 subjects, 1,964 (76.2 percent) had all four third-molar teeth, 238 (9.2 percent) had three, 214 (8.3 percent) had two, 66 (2.6 percent) had one third molar, and 97 (3.8 percent) had agenesis of all third-molar teeth. There was no significant difference in agenesis of third-molar teeth between the right and left sides and no gender predilection was noted. However, significantly more third-molar teeth were found to be missing from the maxilla compared to the mandible, with a ratio of approximately 1.5:1. CONCLUSION: According to our results, the absence of one third molar is the most frequently detected pattern in the East Anatolian population. Additionally, the absence of third molars is more frequent in the maxilla than the mandible. CLINICAL SIGNIFICANCE: To date no information about third-molar agenesis in the East Anatolian population from Turkey is documented. This is believed to be the first known study on this subject in this population.

Effects of orthodontic treatment and premolar extractions on the mandibular third molars.

BACKGROUND: The space available for an unerupted mandibular third may depend on the choice of premolar extracted. AIMS: To investigate the effects of orthodontic treatment and premolar extractions on the inclinations of the mandibular third molars and the space available for their eruption, and to compare these changes with a nonextraction group. METHODS: The pre- and post-treatment panoramic radiographs of 54 subjects (20 males, 34 females) were used. Eighteen of these subjects had the four first premolars extracted, 16 subjects had four second premolars extracted and 20 subjects were treated nonextraction. Changes in the inclinations and spaces available for the unerupted third molars were compared. RESULTS: In the nonextraction group the third molars uprighted approximately 1 degree and in the second premolar extraction group the third molars uprighted 10 degrees. The spaces available for the third molars increased significantly in the first and second premolar extraction groups as compared with the space available in the nonextraction group. CONCLUSIONS: Orthodontic treatment and extraction of the second premolars improved the inclinations of unerupted third molars and the space available for their eruption into the arch. The changes in inclination and eruption space were less marked following first premolar extractions.

Effects of rapid maxillary expansion on nasal breathing and some naso-respiratory and breathing problems in growing children: a literature review.

OBJECTIVE: Rapid maxillary expansion (RME) is a dentofacial orthopedic treatment procedure which has been routinely used in young patients. Main goal of RME is to correct the existing posterior crossbite and to widen the maxilla and maxillary dental arch. However, a concomitant and contributing benefit of this procedure is an improvement on nasal airway which facilitates nasal respiration. RME brings about not only an increase in nasopharyngeal airway dimensions and an improvement in nasal respiration but also a decrease in naso-respiratory problems of the patients having maxillary constriction and mouth breathing. The purpose of this article is to review the effects of RME on naso-respiratory and breathing problems caused by maxillary constriction and mouth breathing in growing children. CONCLUSION: Although orthodontic treatment is carried out to correct dental and skeletal discrepancies, some authors showed that treatment outcomes of RME could also effective on naso-respiratory and sleep-disordered breathing problems of the growing children. However, it must be kept in mind that this respect of RME was evaluated in a little number of studies and had a low-level of evidence.

Condylar asymmetry in unilateral posterior crossbite patients.

INTRODUCTION: Posterior crossbite is defined as an abnormal buccolingual relationship between opposing posterior teeth including the canines in centric occlusion. The most common form of posterior crossbite is unilateral with a functional shift of the mandible toward the crossbite side. Lateral shift of the mandible in functional crossbite patients results in mandibular skeletal deflection to the crossbite side. Thus, the asymmetrical position of the mandible in these patients can result in asymmetrical condylar heights. The purpose of this study was to investigate condylar and ramal asymmetries in unilateral crossbite patients as compared with normocclusive subjects. METHODS: The study groups included 81 patients with unilateral posterior crossbite and a control group of 75 patients with normal occlusion. Condylar, ramal, and condylar-plus-ramal asymmetry values were computed for all subjects on panoramic radiographs. Data were analyzed statistically with ANOVA for repeated measures and univariate ANOVA. RESULTS: The patients with unilateral posterior crossbite had more asymmetric condyles than did the controls. In addition, condylar, ramal, and condylar-plus-ramal heights on the crossbite side were smaller than those on the noncrossbite side. CONCLUSIONS: Subjects with functional unilateral posterior crossbite have asymmetrical condyles.

Effects of semirapid maxillary expansion on conductive hearing loss.

INTRODUCTION: Conductive hearing loss is affected by physical changes imposed on the mechanical system of the outer or middle ear. Maxillary expansion can affect conductive hearing loss, and the changes have been investigated with pure-tone audiograms. Semirapid and slow methods of maxillary expansion have some advantages over rapid maxillary expansion, but the effects on conductive hearing loss have not been investigated. The purpose of this study was to investigate long-term effects of semirapid maxillary expansion (SRME) with an acrylic bonded appliance on conductive hearing loss by using audiometric and tympanometric records. METHODS: The effects of SRME with a bonded appliance were studied in 19 growing subjects who had narrow maxillary arches and conductive hearing loss. Hearing levels were determined with pure-tone audiometric and tympanometric records. Four records were taken from each subject. The first records were taken before SRME, the second after maxillary expansion (mean, 3.4 months later), the third after retention (mean, 6 months later), and the fourth after fixed-appliance treatment (approximately 2 years later). The data were analyzed with ANOVA. The least-significant difference test was also used to determine when the changes in the measurements were significant. RESULTS: Hearing improved and air-bone gaps decreased at a statistically significant level after active expansion, and these changes remained relatively stable during the last 2 periods. Middle-ear volume increased at a statistically significant level after maxillary expansion and continued to increase until the end of treatment. No significant change was observed in the static compliance value. CONCLUSIONS: SRME treatment has a positive and statistically significant effect on both hearing and normal functioning of the eustachian tubes in patients with transverse maxillary deficiency and conductive hearing loss.

Maxillary protraction appliance effect on the size of the upper airway passage.

OBJECTIVE: To test the hypothesis that maxillary protraction appliances (MPA) have no effect on the size of the upper airway passage and craniofacial structures in adolescent patients. MATERIALS AND METHODS: Twenty patients (5 male and 15 female; mean age 11.5 years) with skeletal Class III malocclusion were included in this study. The records of all patients who had maxillary protraction treatment and had lateral head radiographs taken before and after their protraction treatments were obtained from the files of treated cases. Treatment changes were determined by means of linear, angular, and area measurements. Data were analyzed statistically by means of paired t-test and correlation analysis. RESULTS: Significant increases were observed in the width and area of the pharyngeal airway. Significant increases also occurred in the sagittal growth of the maxilla, while a clockwise rotation and inhibition of sagittal growth were observed in the mandible. CONCLUSIONS: The hypothesis was rejected. The size of the upper airway can be increased by means of MPA application.