Guiding the Child's Teeth with Class III Dental Malocclusion into Correct Occlusion: A Clinician's Parenting.

Pediatric dentists are often the first ones to be consulted for the presence of an anterior cross bite in the primary dentition. The condition requires an early interception to avoid progressive dentoalveolar and skeletal changes. The management, however, poses unique challenges in terms of young age of the child, correct choice of appliance and unpredictability of the response to treatment due to inability to ascertain the inherent growth potential. It is very important therefore for the specialist, to be able to recognize the early signs of a developing class III malocclusion tendency and also know the basic details of successful management of such cases. The following article describes the appropriateness of appliance choice for a case of incisor cross bite in primary dentition using different appliances based on their varied clinical presentations.

Cell and matrix response of temporomandibular cartilage to mechanical loading.

OBJECTIVES: The generation of transgenic mice expressing green fluorescent proteins (GFPs) has greatly aided our understanding of the development of connective tissues such as bone and cartilage. Perturbation of a biological system such as the temporomandibular joint (TMJ) within its adaptive remodeling capacity is particularly useful in analyzing cellular lineage progression. The objectives of this study were to determine: (i) if GFP reporters expressed in the TMJ indicate the different stages of cell maturation in fibrocartilage and (ii) how mechanical loading affects cellular response in different regions of the cartilage. DESIGN/METHODS: Four-week-old transgenic mice harboring combinations of fluorescent reporters (Dkk3-eGFP, Col1a1(3.6 kb)-GFPcyan, Col1a1(3.6 kb)-GFPtpz, Col2a1-GFPcyan, and Col10a1-RFPcherry) were used to analyze the expression pattern of transgenes in the mandibular condylar cartilage (MCC). To study the effect of TMJ loading, animals were subjected to forced mouth opening with custom springs exerting 50 g force for 1 h/day for 5 days. Dynamic mineralization and cellular proliferation (EdU-labeling) were assessed in loaded vs control mice. RESULTS: Dkk3 expression was seen in the superficial zone of the MCC, followed by Col1 in the cartilage zone, Col2 in the prehypertrophic zone, and Col10 in the hypertrophic zone at and below the tidemark. TMJ loading increased expression of the GFP reporters and EdU-labeling of cells in the cartilage, resulting in a thickness increase of all layers of the cartilage. In addition, mineral apposition increased resulting in Col10 expression by unmineralized cells above the tidemark. CONCLUSION: The TMJ responded to static loading by forming thicker cartilage through adaptive remodeling.

Evaluation of BSP expression and apoptosis in the periodontal ligament during orthodontic relapse: a preliminary study.

OBJECTIVE: To examine the expression of bone sialoprotein (BSP) and apoptosis in an in vivo orthodontic relapse model. MATERIALS AND METHODS: Male mice (10-12 weeks old), either transgenic [green fluorescent protein (GFP) driven by the BSP promoter] or wild type, were used in this study. To achieve orthodontic tooth movement (OTM), maxillary right first molars were moved mesially using closed-coil springs. Animals were divided into an OTM group (14 days continuous orthodontic force - 11 animals) or Relapse group (10 days of force application followed by 4 days of relapse - 8 animals). The control group was comprised of the contralateral maxillary molars. The periodontal ligament (PDL) was analyzed in areas of compression and tension for transgenic expression, osteoclast localization, and the presence of apoptotic cells. RESULTS: There was a significant decrease in GFP-labeled cells on the compression and tension sides of the PDL in the OTM group compared with control. In the relapse group, GFP-labeled cells were significantly decreased only on the old compression side. Osteoclasts were localized on the compression side of the OTM group, whereas in the Relapse group, they were present on both sides. PDL apoptosis significantly increased on the compression side in OTM and Relapse groups. CONCLUSION: Both OTM and Relapse groups exhibited a decreased number of GFP-labeled cells in areas of compression and tension. There was significant PDL apoptosis in regions under compressive forces following OTM and to a lesser extent following relapse.

Dental Anomalies Associated with Craniometaphyseal Dysplasia.

Craniometaphyseal dysplasia (CMD) is a rare genetic disorder encompassing hyperostosis of craniofacial bones and metaphyseal widening of tubular bones. Dental abnormalities are features of CMD that have been little discussed in the literature. We performed dentofacial examination of patients with CMD and evaluated consequences of orthodontic movement in a mouse model carrying a CMD knock-in (KI) mutation (Phe377del) in the Ank gene. All patients have a history of delayed eruption of permanent teeth. Analysis of data obtained by cone-beam computed tomography showed significant bucco-lingual expansion of jawbones, more pronounced in mandibles than in maxillae. There was no measurable increase in bone density compared with that in unaffected individuals. Orthodontic cephalometric analysis showed that patients with CMD tend to have a short anterior cranial base, short upper facial height, and short maxillary length. Microcomputed tomography (micro-CT) analysis in homozygous Ank (KI/KI) mice, a model for CMD, showed that molars can be moved by orthodontic force without ankylosis, however, at a slower rate compared with those in wild-type Ank (+/+) mice (p < .05). Histological analysis of molars in Ank (KI/KI) mice revealed decreased numbers of TRAP(+) osteoclasts on the bone surface of pressure sides. Based on these findings, recommendations for the dental treatment of patients with CMD are provided.

Dental extraction as a risk factor for bisphosphonate related osteonecrosis of the jaw in cancer patients: an update.

UNLABELLED: Osteonecrosis of the jaw (ONJ) is a complication related to the use of bisphosphonates (BPs). Patients receiving BPs for the treatment of malignancies are at an increased risk of developing bisphosphonate-related ONJ (BRONJ) as compared to patients receiving BPs for the treatment of other disorders such as osteoporosis. Additionally, tooth extractions have been suggested to increase the risk of BRONJ in individuals taking BPs. OBJECTIVE: To review the role of dental extraction as a risk factor for BRONJ in cancer patients. MATERIALS AND METHODS: Databases were searched from January 1999 up to and including July 2012 using various combinations of the following keywords: "bisphosphonate", "osteonecrosis of the jaw", "cancer", "oral" and "dental extraction". RESULTS: Twenty two studies were included. Eighteen studies assessed the relationship between BRONJ and dental extractions in cancer patients, reporting the overall prevalence of BRONJ following extraction in this group as 3.25 +/- 2.23%. Four studies did not report a correlation between BRONJ and extractions, and recommended protocols to avoid the complication. CONCLUSION: There is a plausible relationship between dental extractions and the development of BRONJ in cancer patients. Written informed consent must be obtained prior to dental procedures in patients at risk for developing BRONJ.

Orthodontic movement of a maxillary central incisor with a horizontal root fracture treated using an intra-radicular fibre splint.

This paper reports the case of a 15-year-old boy with a horizontal root fracture in the left maxillary central incisor along with class II division 1 malocclusion for whom a fixed orthodontic treatment was planned. The fracture was present at the junction of apical and middle-third as a result of trauma 2 years back. No splinting was carried out at that time and the tooth was found to be vital, asymptomatic and showed a type-1 repair pattern. An intentional root canal treatment was carried out for placement of an intra-radicular fiber splint, nearly 3 mm beyond the fracture line. Orthodontic treatment was initiated after a month; to which the fractured and splinted tooth responded successfully. This report highlights the successful use of an intra-radicular splint for horizontally fractured tooth requiring orthodontic treatment.

Orthodontic tooth movement causes decreased promoter expression of collagen type 1, bone sialoprotein and alpha-smooth muscle actin in the periodontal ligament.

OBJECTIVE: To evaluate the effects of orthodontic tooth movement on the promoter expression of collagen type 1 (3.6Col1), bone sialoprotein (BSP) and alpha-smooth muscle actin (αSMA) in the periodontal ligament (PDL) using transgenic mice containing transgenes of these promoters fused to green fluorescent proteins (GFP). MATERIALS AND METHODS: The maxillary first molars of 10-12 week-old transgenic mice were loaded with 10-12 g of force for 12, 48 h, or 7 days. Mice were transgenic for one of the following GFP-tagged bone markers of osteoblast lineage cells: 3.6-kb fragment of the rat collagen type 1 promoter (3.6Col1), BSP or α-smooth muscle actin (αSMA). Loaded molars under compression and tension were compared with contra-lateral unloaded controls. RESULTS: On the compression side of the PDL, orthodontic tooth movement caused a significant decrease in GFP expression of all the promoters at each time point. On the tension side, there was a significant increase in BSP-GFP expression, 12 h following loading compared to the contralateral unloaded controls. CONCLUSIONS: An in vivo tooth movement model using transgenic mice with promoter-GFP constructs provides an efficient and effective way of investigating the cellular events underlying orthodontic tooth movement. PDL cells may undergo decreased differentiation in response to the compressive force.

Isolation and characterization of murine mandibular condylar cartilage cell populations.

OBJECTIVES: The mandibular condylar cartilage is a heterogeneous tissue containing cells at various stages of chondrocyte maturation organized into 4 zones: superficial, polymorphic, flattened, and hypertrophic. The goal of this study was to use transgenic mice containing chondrocyte maturation markers fused to fluorescent protein transgenes to isolate and characterize homogenous cell populations of the mandibular condylar cartilage. METHODS: Fluorescent reporter expression in the mandibular condylar cartilage of transgenic mice containing the 3.6-kb fragment of the rat collagen type 1 promoter fused to a topaz-fluorescent protein (Col3.6-tpz), collagen type 2 promoter fused to a cyan-fluorescent protein (Col2-cyan), and/or collagen type 10 promoter fused to cherry-fluorescent protein (Col10-cherry) was examined. Mandibular condylar cartilage cells were analyzed by fluorescence-activated cell sorting (FACS) and either used for gene expression analysis or plated in cell cultures and exposed to adipogenic, osteogenic, or chondrogenic conditions. To determine cell fate, transgenic mice containing the Col3.6-cre recombinase were bred with cre reporter mice. RESULTS: Localization and analysis of gene expression revealed that Col3.6-tpz-positive cells corresponded to the polymorphic/flattened zones and Col2-cyan-positive cells corresponded to the flattened/hypertrophic zones of the mandibular condylar cartilage. Mandibular condylar cartilage FACS-sorted Col3.6-tpz-positive cells have the potential to differentiate into bone, cartilage, and fat. Cell fate mapping revealed that Col3.6 cells are precursors of some of the hypertrophic chondrocytes in the mandibular condylar cartilage. CONCLUSION: Col3.6-tpz cells represent an earlier stage of the mandibular condylar cartilage maturation pathway.

Sex differences in chondrocyte maturation in the mandibular condyle from a decreased occlusal loading model.

Temporomandibular joint disorders (TMDs) predominantly afflict women of childbearing age. Defects in mechanical loading-induced temporomandibular joint (TMJ) remodeling are believed to be a major etiological factor in the development of TMD. The goal of this study was to determine if there are sex differences in CD-1 and C57BL/6 mice exposed to a decreased occlusal loading TMJ remodeling model. Male and female CD-1 and C57BL/6 mice, 21 days old, were each divided into two groups. They were fed either a normal pellet diet (normal loading) or a soft diet and had their incisors trimmed out of occlusion (decreased occlusal loading) for 4 weeks. The mandibular condylar cartilage was evaluated by histology, and the subchondral bone was evaluated by micro-CT analysis. Gene expression from both was evaluated by real-time PCR analysis. In both strains and sexes of mice, decreased occlusal loading caused similar effects in the subchondral bone, decreases in bone volume and total volume compared with their normal loading controls. However, in both strains, decreased occlusal loading caused a significant decrease in the expression of collagen type II (Col2) and Sox9 only in female mice, but not in male mice, compared with their normal loading controls. Decreased occlusal loading causes decreased bone volume in both sexes and a decrease in early chondrocyte maturation exclusively in female mice.

Murine TMJ loading causes increased proliferation and chondrocyte maturation.

The purpose of this study was to examine the effects of forced mouth opening on murine mandibular condylar head remodeling. We hypothesized that forced mouth opening would cause an anabolic response in the mandibular condylar cartilage. Six-week-old female C57BL/6 mice were divided into 3 groups: (1) control, (2) 0.25 N, and (3) 0.50 N of forced mouth opening. Gene expression, micro-CT, and proliferation were analyzed. 0.5 N of forced mouth opening caused a significant increase in mRNA expression of Pthrp, Sox9, and Collagen2a1, a significant increase in proliferation, and a significant increase in trabecular spacing in the subchondral bone, whereas 0.25 N of forced mouth opening did not cause any significant changes in any of the parameters examined. Forced mouth opening causes an increase in the expression of chondrocyte maturation markers and an increase in subchondral trabecular spacing.

Spurious and counterfeit drugs: a growing industry in the developing world.

Spread of spurious/counterfeit/substandard drugs is a modern day menace which has been recognised internationally, especially so in developing countries. The problem assumes added significance in view of rapid globalisation. The market of spurious and counterfeit drugs is a well-organised, white collar crime. Poverty, high cost of medicines, lack of an official supply chain, legislative lacunae, easy accessibility to computerised printing technology, ineffective law enforcement machinery, and light penalties provide the counterfeiters with an enormous economic incentive without much risk. The consequences of the use of such medicines may vary from therapeutic failure to the occurrence of serious adverse events and even death. Proper drug quality monitoring, enforcement of laws and legislation, an effective and efficient regulatory environment, and awareness and vigilance on part of all stakeholders can help tackle this problem.

Early class III occlusal tendency in children and its selective management.

Class III malocclusion may develop in children as a result of an inherent growth abnormality, i.e., true class III malocclusion, or as a result of premature occlusal contacts causing forward functional shift of the mandible, which is known as pseudo class III malocclusion. These cases, if not treated at the initial stage of development, interfere with normal growth of the skeletal bases and may result in severe facial deformities. The treatment should be carried out as early as possible with the aim of permitting normal growth. This paper deals with the selection of an appropriate treatment approach from the various current options available for early intervention in children developing class III occlusal tendencies; the different clinical features are depicted in the three case reports.

Distribution of malocclusion types among thumb suckers seeking orthodontic treatment.

UNLABELLED: The present study was conducted to evaluate the influence of thumb sucking and its duration on the type of malocclusion. A total of 410 North Indian individuals between ages 12-30 years, 161 males and 249 females were examined. A specially designed proforma was used to record the detailed history of the individual. Among the etiological factors it was found that history of thumb sucking was present in 13.9% and significantly related to Class II div 1 malocclusion. When thumb sucking exceeded 18 months, it was found statistically significant (P < 0.1) in Class II skeletal malocclusion, in open bite (P < 0.1) and in extreme overjet (P < 0.5). CONCLUSION: If thumb sucking is not treated early, it can cause skeletal Class II malocclusion, anterior open bite and excessive overjet.

Is tongue thrust that develops during orthodontic treatment an unrecognized potential road block?

The role of tongue thrust has often been suspected, long debated and largely dispelled as a primary etiological factor of malocclusion. However, tongue thrust may contribute to poor occlusal intercuspation both during and after treatment. A tongue thrust may also develop during orthodontic mechanotherapy as a result of the transient creation of intra and interarch spaces and this little recognized phenomenon was found to occur in many randomly followed cases. In many instances, this seemingly adaptive and secondary response of the tongue posture and function may persist and thereafter impede the resolution of intra and interarch problems.

Effects of variation in the timing of palatal repair on sagittal craniofacial morphology in complete cleft lip and palate children.

The complete cleft lip and palate children, ranging from 6-14 years of age were studied to evaluate the effect of variation in the timing of palatal repair on craniofacial morphology and compared to the noncleft children. It was observed that all the groups early (8 to < or = 24 months), medium (> 24 to < or = 36 months) and late repair (> 36 to < or = 78 months) had significantly larger cranial base, retruded maxillomandibular relations, skeletodental and incisal relationships compared to the noncleft children. However, intercomparison among the cleft groups showed insignificant difference amongst them suggesting that the timing of palatal repairs does not effect the anterioposterior (sagittal) relationship.

Effects of variation in timing of palatal repair on articulation skills in complete cleft lip and palate cases--a retrospective study.

The effects of variation in the timing of palatal repair on articulation skills in complete cleft lip and palate was evaluated from fifty subjects. The present study confirmed that development of articulation was similar in the groups operated upon before 24 months and between 24 to 36 months. The insignificant difference suggests that articulation was good irrespective of the early or medium timing of palatal repair.

Effects of variation of the timing of palatal repair on nasality of speech in complete cleft lip and palate children.

Nasality is related to factors like velopharyngeal closure and acoustic factors pertaining to cavities. The present investigation is a retrospective study aimed at evaluating the effects of variation in the timing of palatal repair on nasality during speech development in complete cleft lip and palate cases. It has been observed that the delay in palatal repair is associated with increase in nasality. Also, from the operated complete cleft lip and palate cases, it has been observed that the early and medium repair groups had almost similar effects on nasality of speech. (if they were operated before 36 months of age).

Prevalence of malocclusion and abnormal oral habits in North Indian rural children.

This epidemiological investigation was conducted on a sample of 3164 rural children aged 6-15 years in Raipur Rani and Naraingarh blocks in the district of Ambala in Haryana. 29. 2 percent of rural children were found to have malocclusion whereas 70.8 per cent had normal occlusion. Class I malocclusion was found to be maximum in 14.4 per cent of children, while malocclusion with class II molar relationship was observed in 13.5 per cent of children. Malocclusion with Class III molar relationship was seen in 1.3 per cent of the population studied. Three per cent of rural children were found to have abnormal oral habits, predominantly tongue thrusting and thumb sucking. The frequency distribution of abnormal oral habits in children with malocclusion was found to be 10.3 per cent.

Non-familial cherubism--a case report.

A case of cherubism in a 9 year old boy with no familial history is presented. Clinical features, histologic appearance, radiographic findings, differential diagnosis and rationale for treatment is discussed.