Mandibular Growth Research Articles

Conservative Decompression Management with Functional Appliance in Pediatric Plexiform Ameloblastoma

Ameloblastoma is an infiltrative benign neoplasm in the mandible or maxilla that is locally aggressive with rare metastasizing capacity. This lesion is the most common tumor of the odontogenic epithelium. However, its occurrence in children is low, representing only 10–15% of all reported ameloblastoma cases. In treating such benign neoplasms in pediatric patients, the preservation of vital structures such as the inferior alveolar nerve (IAN), deciduous teeth, tooth buds, and nerves with proper post-operative management to maintain normal mandibular growth is imperative. A five-year-old boy with painless swelling and displaced teeth in the right mandible was diagnosed with plexiform ameloblastoma. Instead of a radical approach, the patient was treated conservatively using decompression and routine irrigation along with long-term follow-up. Functional appliance treatment was provided using a Frankel appliance to preserve and induce normal growth of the jaw. After eight years, there was no recurrence of the ameloblastoma, and normal mandibular growth of the patient was observed. Pediatric plexiform ameloblastoma should be treated with a conservative approach considering the preservation of important anatomic structures and further mandibular growth. Moreover, functional appliance therapy should be considered as an integral part of treatment for pediatric ameloblastoma and other tumors in children to maintain and induce normal growth of the mandible.

Effects of estrogen deficiency during puberty on maxillary and mandibular growth and associated gene expression \u2013 an \u03bcCT study on rats

BackgroundEstrogen is a well-known and important hormone involved in skeletal homeostasis, which regulates genes involved in bone biology. Some studies support that estrogen is important for craniofacial growth and development. Therefore this in vivo animal study aimed to investigate, whether and in which way low estrogen levels in the prepubertal period affect craniofacial development in the postpubertal stage and to quantify the gene expression of RANK, RANKL and OPG in cranial growth sites in ovariectomized estrogen-deficient rats during puberty.MethodsControl (sham-operated, n = 18) and ovariectomy (OVX, n = 18) surgeries were performed on 21-days-old female Wistar rats. Animals euthanized at an age of 45 days (pubertal stage) were used for gene expression analyses (n = 6 per group) and immunohistochemistry of RANK, RANKL and OPG. Animals euthanized at 63 days of age (post-pubertal stage) were used for craniofacial two-dimensional and three-dimensional craniofacial measurements using μCT imaging (n = 12 per group).ResultsIn the μCT analysis of the mandible and maxilla many statistically significant differences between sham-operated and OVX groups were observed, such as increased maxillary and mandibular bone length in OVX animals (p < 0.05). Condylar volume was also significantly different between groups (p < 0.05). The sham-operated group showed a higher level of RANK expression in the midpalatal suture (p = 0.036) and the RANKL:OPG ratio levels were higher in the OVX group (p = 0.015).ConclusionsOur results suggest that estrogen deficiency during the prepubertal period is associated with alterations in the maxillary and mandibular bone length and condylar growth.

The Fibroblast Growth Factor 9 (Fgf9) Participates in Palatogenesis by Promoting Palatal Growth and Elevation.

Cleft palate, a common global congenital malformation, occurs due to disturbances in palatal growth, elevation, contact, and fusion during palatogenesis. The Fibroblast growth factor 9 (FGF9) mutation has been discovered in humans with cleft lip and palate. Fgf9 is expressed in both the epithelium and mesenchyme, with temporospatial diversity during palatogenesis. However, the specific role of Fgf9 in palatogenesis has not been extensively discussed. Herein, we used Ddx4-Cre mice to generate an Fgf9–/– mouse model (with an Fgf9 exon 2 deletion) that exhibited a craniofacial syndrome involving a cleft palate and deficient mandibular size with 100% penetrance. A smaller palatal shelf size, delayed palatal elevation, and contact failure were investigated to be the intrinsic causes for cleft palate. Hyaluronic acid accumulation in the extracellular matrix (ECM) sharply decreased, while the cell density correspondingly increased in Fgf9–/– mice. Additionally, significant decreases in cell proliferation were discovered in not only the palatal epithelium and mesenchyme but also among cells in Meckel’s cartilage and around the mandibular bone in Fgf9–/– mice. Serial sections of embryonic heads dissected at embryonic day 14.5 (E14.5) were subjected to craniofacial morphometric measurement. This highlighted the reduced oral volume owing to abnormal tongue size and descent, and insufficient mandibular size, which disturbed palatal elevation in Fgf9–/– mice. These results indicate that Fgf9 facilitates palatal growth and timely elevation by regulating cell proliferation and hyaluronic acid accumulation. Moreover, Fgf9 ensures that the palatal elevation process has adequate space by influencing tongue descent, tongue morphology, and mandibular growth.

Reconstruction of the Mandibular Condyle.

The mandibular condyle is an integral structure in the temporomandibular joint (TMJ) serving not only as the hinge point for mandibular opening, but also facilitating mandibular growth and contributing to facial aesthetics. Significant compromise of the TMJ can be debilitating functionally, psychologically, and aesthetically. Reconstruction of the mandibular condyle is rarely straightforward. Multiple considerations must be accounted for when preparing for condylar reconstruction such as ensuring eradication of all chronically diseased or infected bone, proving clear oncologic margins following tumor resection, or achieving stability of the surrounding architecture in the setting of a traumatic injury. Today, there is not one single gold-standard reconstructive method or material; ongoing investigation and innovation continue to improve and transform condylar reconstruction. Herein, we review methods of condylar reconstruction focusing on autologous and alloplastic materials, surgical techniques, and recent technological advances.

Modelling growth curves of the normal infant\u2019s mandible: 3D measurements using computed tomography

ObjectivesData on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age.Material and methods3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed.ResultsIn this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed.ConclusionsAnalysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months.Clinical relevanceThese growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.

Longitudinal Follow-Up of Facial Growth of Patients With Unilateral Cleft Lip and Palate Following Modified Veau-Wardill-Kilner Palatoplasty.

To evaluate facial growth after modified Veau-Wardill-Kilner/pushback (PB) palatoplasty from childhood to adulthood in patients with unilateral cleft lip and palate (UCLP). Retrospective longitudinal study. Single center. Sixty-two (29 males and 33 females) consecutive patients with nonsyndromic UCLP. Pushback palatoplasty and subsequent cleft palate treatment. Lateral and posterior-anterior cephalograms were taken at 3 different phases: phase 1 (before first-stage orthodontic treatment; N = 58; average age, 4.9 ± 1.1 years), phase 2 (before second-stage orthodontic treatment; N = 58; 15.9 ± 1.1 years), and phase 3 (after orthodontic retention; N = 51; 22.1 ± 3.2 years). The majority of patients had skeletal class III morphology in all 3 phases due to retrognathic maxilla. Maxillary growth did not improve in phase 2 despite first-stage orthodontic treatment in phase 1. Maxillary morphology improved in phase 3 but retardation occurred, although 77.42% of patients received orthognathic surgery during second-stage orthodontic treatment. Mandibular growth was slightly reduced in phases 1 and 2 and the mandible remained retrognathic in phase 3, following mandibular setback orthognathic surgery. The horizontal occlusal cant was slightly upward and toward the cleft side with respect to the reference plane, and the upper midline was deviated to the cleft side in phases 1 and 3. Patients with UCLP who undergo phased PB palatoplasty, orthodontic treatment, and orthognathic surgeries do not maintain skeletal class I facial morphology.

Methods in Genetic Analysis for Evaluation Mandibular Shape and Size Variations in Human Mandible.

The human mandible has been investigated from both clinical and evolutionary perspectives. Recent advances in genome science have identified the genetic regulation of human mandibular shape and size. Identification of genes that regulate mandibular shape and size would not only enhance our understanding of the mechanisms of mandibular growth and development but also help define a strategy to prevent mandibular dysplasia. This review provides a comprehensive summary of why and how the mandible was evaluated in the human mandible genome study. The variation in human mandibular shape and size has been progressively clarified, not only by focusing on the mandible alone but also by using extremely diverse approaches. The methods of data acquisition for evaluating human mandibular shape and size variation are well established. Furthermore, this review explains how to proceed with future research.

Comparative evaluation of Skeletal, Dental, and Soft Tissue Changes in Class II Division 1 Malocclusion Cases Treated with Twin Block and innovative Clear Block Appliance - A Prospective Interventional Study

The present study was undertaken to evaluate and compare the skeletal, dental, and soft tissue changes in skeletal Class II division 1 cases treated with Twin Block and Clear Block appliances using a cephalogram. A total of 40 patients of age between 12-14 years were randomly divided into two equal groups. Group 1: treated with Twin Block appliance and Group 2: treated with Clear Block appliance. The pre-treatment lateral cephalogram was taken and skeletal, dental, and soft tissue parameters were evaluated and the appliance was delivered. After 8 months, another lateral cephalogram of all the cases was taken and analyzed. The pre and post-treatment values were compared between the two groups. The pre-treatment cases were almost comparable in skeletal, dental, and soft tissue features in both groups. There was a significant change in mandibular growth by SNB angle. The retrusion and extrusion of maxillary incisors as well as a proclination and extrusion of mandibular incisors were seen in group 1 while no change was observed in group 2. Treatment with Clear Block appliances has shown significant and favorable Skeletal, Dental and Soft tissue changes which are similar to already proven by the Twin Block appliance. Clear Block provides an esthetic and less bulky option for growth modification with similar results as compared to conventional Twin Block with the additional benefit of preventing lower incisor proclination.

Pediatric Malignant Mandibular Tumors: Personal Experience and Literature Options Discussion

Introduction: Mandibular defects reconstruction could result challenging in childhood, due to facial and mandibular growth patterns. For these reasons, the choice of the most suitable reconstructive option in pediatric patients, affected by mandibular malignancies, still objects of debate. Objective: The aim of our study was to compare our reconstructive schedules to the existing literature in order to give a personal contribute to the present panorama. Methods: We performed, in October 2019, a retrospective evaluation of pediatric patients treated for biopsy-proven mandibular malignancies at our Institute between January 2013 and December 2016. All of them received multimodal therapy in accordance with standard guidelines and their demographic, clinical, treatment, and outcome parameters were collected and analyzed. Results: We observed a shorter duration of surgery, a faster tracheostomy tube and feeding-tube removal, and a minor hospitalization in patients who received grafts transfer compared to those who underwent microsurgical mandibular reconstruction. After a 36-month period of follow-up, osteochondral grafts showed a pattern of growth similar to the mandibular epiphysis (condilylion-gonion linear and vertical ratio ranging to 0.96–1.03 and 1–1.02 at orthopantomogram, respectively). No bone consolidation delays and functional impairment were recorded. Conclusions: Free flaps mandibular reconstruction in children needs to be better assessed and proximal fibular epiphyseal free flap indication might deserve further studies. Osteochondral grafts find indication for lateral defects, 50–55 mm in maximum length and located in the mandibular ramus, without massive teeth or soft tissue defect. Condyle involvement does not represent an absolute contraindication to rib graft use.

How to use a nasopharyngeal prong in Pierre Robin sequence

Abstract Pierre Robin sequence (PRS) describes a small mandible with retrognathia, an elevated and posteriorly positioned tongue, and an associated U-shaped cleft palate. The retracted tongue may obstruct the airway leading to respiratory failure, with failure to thrive and adverse neurodevelopmental outcomes if not addressed. If the airway obstruction cannot be overcome with conservative measures, there are non-surgical and surgical options. A nasopharyngeal prong (NPP) is a non-surgical, temporary treatment that avoids the complications inherent in an operation, especially given the natural history of mandibular growth and improved airway obstruction in PRS. Although the use of a prong requires training, support, and follow up, it effectively bypasses the obstruction in the majority of children with PRS, and allows the child to outgrow the airway obstruction until the prong is no longer required. On average, the prong can be removed between 6 and 12 months of age.

Potential impact of pediatric obstructive sleep apnea on mandibular cortical width dimensions.

To analyze differences in mandibular cortical width (MCW) among children diagnosed with obstructive sleep apnea (OSA) or at high- or low-risk for OSA. A total of 161 children were assessed: 60 children with polysomnographically diagnosed OSA, 56 children presenting symptoms suggestive of high-risk for OSA, and 45 children at low risk for OSA. Children at high- and low-risk for OSA were evaluated through the Pediatric Sleep Questionnaire. MCW was calculated using ImageJ software from panoramic radiograph images available from all participants. Differences between MCW measurements in the 3 groups were evaluated using analysis of covariance and Bonferroni post-hoc tests, with age as a covariate. The association between MCW and specific cephalometric variables was assessed through regression analysis. The participants' mean age was 9.6 ± 3.1 years (59% male and 41% female). The mean body mass index z-score was 0.62 ± 1.3. The polysomnographically diagnosed OSA group presented smaller MCW than the group at low-risk for OSA (mean difference = -0.385 mm, P = .001), but no difference with the group at high-risk for OSA (polysomnographically diagnosed OSA vs high-risk OSA: P = .085). In addition, the MCW in the group at high-risk for the OSA was significantly smaller than the group at low-risk for the OSA (mean difference = -0.301 mm, P = .014). The cephalometric variables (Sella-Nasion-A point angle (SNA) and Frankfort - Mandibular Plane angle (FMA)) explained only 8% of the variance in MCW. Reductions in MCW appear to be present among children with OSA or those at high-risk for OSA, suggesting potential interactions between mandibular bone development and/or homeostasis and pediatric OSA. Fernandes Fagundes NC, d'Apuzzo F, Perillo L, et al. Potential impact of pediatric obstructive sleep apnea on mandibular cortical width dimensions. J Clin Sleep Med. 2021;17(8):1627-1634.

Posterior Mandibular Displacement-A Systematic Review Based on Animal Studies.

Simple SummaryExtreme growth of the lower jaw is an essential determinant of facial appearance and treatment is challenging. The mandibular joint is important for mandibular growth and backward traction may be applied to address its protrusion. Nevertheless, the conclusions following animal experiments have been contradictory; additionally, joint disorders could arise because of abnormal, traumatic pressure. Our aim was to review the impact on the condyle and the jaw of their distal displacement as found in published research involving rats and rabbits, up to October 2020. In those animals, the mandibular/condylar retraction led to occlusal improvement, but some relapse might be anticipated. The mandibular condyle remained more posteriorly, restriction of further growth was observed, the posterior surface became more flattened, but it became thicker in its neck. The dimensional alterations persisted for the entire period of study and the mandible resumed its inherited growth pattern after the discontinuation of the orthopedic force. Posterior mandibular displacement may be anticipated to produce clinically significant restriction in condylar growth, mainly attributed to remodeling. The properties of the applied force may affect the timing of mandibular formation or just prove traumatic. Outcome stability is a matter of concern and more studies are required to resolve the issue.Treating extreme mandibular growth is challenging. The mandible is pushed backwards to address itsprotrusion. Nevertheless, conclusions after such displacement in animals have been contradictory. The aim of the present review is to present measurable alterations of the mandible and the condyle following retractionin healthy rats or rabbits. PubMed, Scopus and Web of Science were accessed for relevant studies up to October 2020. Eligibility was determined by the PICOS process, while the risk of bias was estimated with SYRCLE’s risk of bias tool. Retraction resulted in a more distal molar occlusion and the condyle rested more posteriorly. Mandibular anteroposterior bilateral growth restriction was achieved, the condylar process measured smaller and its angulation increased. The condylar neck thickened, its posterior surface flattened, the coronoid process was measured longer, and enlarged retromolar density was registered. Differences in the ramus height and the intercondylar distance were insignificant. Changes persisted for the period of study and subsequently the mandible resumed its inherited growth pattern. The timing of mandibular shaping and TMJ outcomes might depend on the properties of the applied force. Stability is of concern and well-structured, long-term studies are expected to resolve the issue and further clarify the results of posterior mandibular displacement.

Growth and sexual dimorphism of the hyoid bone and its relationship to the mandible from birth to 19 years: A three-dimensional computed tomography study.

The hyoid bone and the hyomandibular complex subserve the functions of respiration, deglutition, and speech. This study quantified the growth of the hyoid bone and the hyomandibular relationships in males and females from birth to 19 years. Using 97 computed tomography (CT) scans, from a previous study (Kelly et al., 2017) on mandibular growth from 49 individuals (16 with longitudinal scans), landmarks were placed on 3D CT models and used to calculate four distance, and three angular measurements. A general increase in growth trend was observed in hyoid bone linear measurements-length, width, and depth-as well as relational mandible-to-hyoid distance, throughout the developmental ages examined in both males and females, with most variables having larger measurements for females up to age 10 years. A general decrease in all three angular measurements was observed in both males and females up to approximately age 12 years, at which time male angular measurements gradually increased with significant sexual dimorphism emerging after age 15 years. As expected, postpubertal males had greater hyoid angle than females; they also had greater hyoid angle of inclination than mandible body inclination (with inclination relative to the anterior-posterior nasal plane), likely related to hyo-laryngeal descent. This study contributes to normative data on hyoid bone and hyomandibular relational growth in typically developing individuals and provides a baseline against which structural and functional influences on anatomic growth may be examined by clinical disciplines that address the aerodigestive and speech functions, as well as the fields of anatomy, forensics, and anthropology.

Novel and Affordable Low-Cost Technique for Fixation of Parasymphyseal Fractures in Infants With Unerupted Dentition

Pediatric mandibular fractures are immensely challenging compared to adult fractures. The current update management spectrum ranges from the conservative one in the form of soft diet and regular follow-up, or less invasive surgical intervention by closed reduction and nonrigid fixation, to open reduction and internal fixation with plates and screws. In this study, we investigated the use of a straightforward fabricated mold for the parasymphyseal mandibular fracture in infants with an unerupted dentition. This prospective study was conducted on 8 infants presenting with parasymphyseal fractures with unerupted dentitions in our specialized trauma center. In the operating room before the induction of anesthesia, the authors used a straightforward plastic airway to create a splint. The curved part was split into 2 transverse halves making 2 U-shaped curved pieces that were utilized as a mold. Intraoperatively, the U-shaped piece was placed over the mandible and stabilized with circummandibular wires. This molded airway is used to stabilize the fracture site for 2-3weeks. The average period of follow-up was around 6months. The average time of mandibular fixation was 17.6±2.4 SD (14 to 20) days. The mean of the total operative time was 38.7±3.5 SD minutes, ranging from 35 to 45minutes. Our infants were observed in the outpatient clinic for 6months postoperatively during the follow-up period. There were no noticeable complications nor any interference with tooth eruption or mandibular growth. The results of this study suggest that this technique is straightforward to use and affordable. It does not require a long learning period. It also exhibits the advantage of reducing the cost in many developing countries.

Environmental Conditions as Epigenetic Modulator of Craniofacial Growth and Development Phenotypes a Mini Review

Environmental variation is translated into phenotypic variation based on how the same genotype can produce a variety of phenotypes across a range of environmental circumstances. Traits showing greater phenotypic variation are either under less direct genetic control and/or mature less rapidly. As expected, the vertical aspects of mandibular growth, which are the least mature in the craniofacial complex, showed the most pronounced effects, developing three types of phenotypes, where normodivergent and hypodivergent have a good facial, but hyperdivergents are the real problem, because they decrease their growth, they are increasing the incidence and prevalence, and with them, are increasing bad functional and esthetics on the population. The environmental conditions that are associated to hyperdivergent phenotype are masticatory loading during early facial growth and airway obstructive problems.

Results of orthodontic treatment of a child with asymmetrical micrognathia and the congenital mandibular condylar hyperplasia

Aim. To analyze the results of orthodontic treatment of a child with asymmetrical micrognathia and mandiblar condylar hyperplasia.&#x0D; Methods. The configuration of a face in the photos was evaluated and diagnostic models of the jaws were analyzed by using the Ponts and Korkhaus methods in treatment dynamics. The physiological status of bone tissue, temporomandibular joints and teeth was studied by using orthopantomography and computed tomography. Functional disorders were detected by using special tests, including EschlerBittner's test and Ilyina-Markosyans test. Orthodontic treatment and stimulation of mandibular growth in the mixed dentition stage were undertaken with the single jaw removable appliances and the appliance improved by us for correction of the distal occlusion. The Damon Q bracket system with archwires was used in permanent dentition period.&#x0D; Results. The child's convex facial profile was typical for distal occlusion and micrognathia. The facial asymmetry, increasing with mouth opening, and a decrease in mandibular range of motion indicated lesion of the right temporomandibular joint. The right condyle was enlarged on the orthopantomogram. The computed tomography showed that it was asymmetrically enlarged and had a cellular structure. There was detected asymmetric micrognathia. The comprehensive rehabilitation plan included orthodontic treatment, myotherapy, speech therapy, mechanotherapy. The use of removable orthodontic appliances led to the normal size of the dentition and their relation, significantly reduced functional disorders and improved facial aesthetics. Five years after completion of orthodontic treatment, the physiological occlusion and amplitude of the mandibular movements remained, but the right mandibular angle was flattened.&#x0D; Conclusion. The comprehensive rehabilitation of a child with asymmetrical micrognathia and mandibular condylar hyperplasia started in mixed dentition stage provided conditions for the formation of normal permanent dentition and the improvement of functional disorders and facial aesthetics; our results allow us to suggest the positive effect of our tactics for treatment of the patient.

Correlation of spheno-occipital synchondrosis fusion stages with a hand-wrist skeletal maturity index: A cone beam computed tomography study.

To examine the correlation between spheno-occipital synchondrosis fusion stages and the hand-wrist skeletal maturity index. Digital records of 164 individuals (77 males, 87 females) aged 10 to 18 years old were examined. Three-dimensional CBCT scans and hand-wrist two-dimensional radiographs were scored for the spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity index, respectively. Statistical analyses were performed for associations using R software with a significance threshold of P< .01. A significant positive relationship was demonstrated between spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity in both sexes. The Kendall's rank correlation τ between hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion percentage were high and positive in males and females (r = .74 and r = .71, respectively). The significant, positive relationship between the hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion stages support the idea of using spheno-occipital synchondrosis fusion as a biological indicator for craniofacial and mandibular growth spurt prediction.

A comparison of 2- and 3-dimensional mandibular superimposition techniques against Björk's structural superimposition method

The purpose of this research was to compare mandibular growth rotation relative to the cranial base in different vertical facial patterns on the basis of multiple 2-dimensional (2D) and 3-dimensional (3D) superimposition methods. Cone-beam computed tomography (CBCT) images taken at a mean interval of 54.8±16.8months were assessed from a sample of 70 growing patients. Three mandibular superimposition methods were compared against Björk's structural method: (1) a 2D landmark method (2D-M1), (2) a voxel-based 3D method based on a previously reported method (3D-M1), and (3) a voxel-based 3D method incorporating symphyseal structures as references (3D-M2). After superimposition, the relative change in cranial base lines as depicted in sagittal views were measured for true mandibular rotation. Agreement between methods was assessed with Lin's concordance correlation coefficient, Bland-Altman's limits of agreement, and the Bradley-Blackwood test. Lin's concordance correlation coefficients ranged between 0.924 for the 2D-M1 method, 0.695 for the 3D-M1 method, and 0.965 for the 3D-M2 method. Bland-Altman limits of agreement were wide for all but the 3D-M2 method. Finally, the Bradley-Blackwood test of equality of means and variances was significant in all except the 3D-M2 method. For time intervals between CBCT volume acquisitions>3years, the use of the 2D-M1 and 3D-M1 methods is not recommended. There was a high concordance between the 3D-M2 method and Björk's structural method when assessing mandibular growth rotation using relative changes in cranial base lines. The high concordance was displayed across all vertical facial types and for all time differences between first and second CBCT data acquisitions.

Effect of Strontium Ranelate on Condylar Growth during Mandibular Advancement in Rats.

Strontium ranelate (SR), unlike other anti-osteoporotic agents, might not only prevent bone resorption but also might induce bone formation. The aim of this experimental study was to evaluate the effects of systemic SR on condylar growth during mandibular advancement (MA) in growing rats. Fifty-six, 8-week-old Wistar male rats weighting 160-190 g were randomly divided into four groups; one control (n=14) and three experimental (n=14). Group 1: Control group, Group 2: SR (900mg/kg daily dose), Group 3: MA, Group 4: SR +MA. The amount and direction of mandibular growth were assessed by linear measurements on the computed tomography (CT) images taken on days 1, 15, and 30. For immunohistochemical evaluation, half of the subjects in the groups were sacrificed on the 15th day (early phase) and the rest of them on the 30th day (late phase). New cartilage and bone formation areas on the condyle were analyzed by using Sox9 and Osteopontin antibodies. Early and late CT images measurements showed no significant difference between the groups (p<0.05). However, there were significant differences between the control and experimental groups in the immunohistochemical assessment. Severe immunolocalization of SOX9 and Osteopontin was observed in Group 4, while the immunolocalization scores were moderate in Group 2 and Group 3. In addition, early histological findings were similar to late results in all groups. In mandibular advancement therapy, Strontium ranelate could be therapeutically effective in avoiding relapse and reducing the duration of retention.

Condylar hypoplasia: Clinical case

The formation of the face and the stomatognathic system is complex in nature and involves the development of multiple tissue processes that must unite and fuse in an extremely orderly manner. Disorders in the growth of these tissue processes or in their fusions can result in facial changes. The temporomandibular joint is one of the most complex in the human body, with the condylar process responsible for the expression of mandibular growth. Condylar hypoplasia is characterized by a defective formation of the condylar process that can be congenital or acquired. In the case presented, the patient has facial asymmetry since the first year of life, only on the left side. Thus, professionals working in the region of the temporomandibular joint must have knowledge of the existence and clinical implications for an early diagnosis in order to avoid the development of facial asymmetries, restoring the patient’s function, aesthetics and psychological status.