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Tetracyclines were introduced as broad spectrum antibiotic for the treatment of various infections, both in children and adults. One of the major drawback with tetracycline is its incorporation into the tooth that are calcifying leading to discoloration which ranges from yellow grey to brownish black as they have the ability to chelate calcium. There is a possibility that this discoloration may not be limited to developing tooth but may also affect adult dentition after eruption. When given over long periods of time in adults, the tetracycline molecule is incorporated into the continuously forming secondary dentin. It is possible that continuous exposure of the incorporated tetracycline to the sun might lead to the formation of oxidation product and lead to discoloration. This case report suggests minimally invasive strategies to manage tetracycline staining in adult dentition. Keywords: Tetracycline stains, Adult dentition, Bleaching, Microabrasion, Direct Veneers.

The aim of this work was to analyse the behaviour of the dental lamina during the development process of first molar teeth. The offspring of female mice were analysed at the 16th day of intra-uterine life and since birth till 17 days old with the aim to evaluate the dental lamina evolution of upper and lower first molars. The animals were sacrificed, and the heads embedded in paraffin in order to get frontal or sagittal sections whose were stained by hematoxylin and eosin method. The results showed a very clear presence of the dental lamina in all periods under analysis, without the occurrence of its disorganization, in other words, it was permanently connecting the developing tooth germ to the oral epithelium until advanced dental eruption.

Objectives: To study the role of amelotin in enamel formation, purified recombinant human amelotin was used in a study of amelotin self assembly and its role in new HAP crstal structure formation in a laboratory setting. Methods: The full-length human amelotin gene was cloned from developing tooth buds and recombinant amelotin was expressed and purified. Morphological changes during amelotin self-assembly and the role of amelotin in promoting new minieralization structure is studied using Transmission electronic microscopy and Scanning electron microscopy. Results: The measured molecular weight of expressed human amelotin was 28 kDa that matches the predicted values. Amelotin self-assembles to form nano-spheres 10 - 30 nm in size. The amelotin self-assembly process further produces higher 3-D structure in the forms of chain-like fabric arranged in parallel and perpendicular direction. The neonatal pearl crystals were arranged side by side to form a string of small rods and small parallel rods extend from the demineralized glaze on the surface of teeth that were pre-treated with amelotin.

Primordial odontogenic tumor (POT) is a rare, mixed odontogenic neoplasm composed of spindled and stellate-shaped cells in myxoid stroma resembling dental papilla, surfaced by cuboidal-to-columnar odontogenic epithelium. Most POTs present in the posterior mandible as a well-demarcated radiolucency associated with a developing tooth in children and adolescents. POT is treated conservatively with no recurrences documented to-date. To describe the clinicopathological features of a recurrent POT. A 19-year-old female presented with an asymptomatic swelling, and panoramic radiograph revealed a multiloculated radiolucency in the mandibular body and ramus, with buccal and lingual perforation. The tumor was composed of plump spindle and stellate cells in a delicately collagenous and myxoid stroma, surfaced by columnar epithelial cells with reverse nuclear polarization. There was extensive epithelial proliferation forming invaginations within the tumor mass and organoid/enamel organ-like structures with enameloid-like deposits, dentinoid, and dystrophic calcifications. This was similar to the POT that had been excised four years prior from the same location. The patient underwent hemi-mandibulectomy and currently is free of disease at a thirteen-month follow-up. This report describes the first recurrent POT exhibiting extensive epithelial proliferation.

Tooth replacement in piranhas is unusual: all teeth on one side of the head are lost as a unit, then replaced simultaneously. We used histology and microCT to examine tooth-replacement modes across carnivorous piranhas and their herbivorous pacu cousins (Serrasalmidae) and then mapped replacement patterns onto a molecular phylogeny. Pacu teeth develop and are replaced in a manner like piranhas. For serrasalmids, unilateral tooth replacement is not an "all or nothing" phenomenon; we demonstrate that both sides of the jaws have developing tooth rows within them, albeit with one side more mineralized than the other. All serrasalmids (except one) share unilateral tooth replacement, so this is not an adaptation for carnivory. All serrasalmids have interlocking teeth; piranhas interdigitate lateral tooth cusps with adjacent teeth, forming a singular saw-like blade, whereas lateral cusps in pacus clasp together. For serrasalmids to have an interlocking dentition, their teeth need to develop and erupt at the same time. We propose that interlocking mechanisms prevent tooth loss and ensure continued functionality of the feeding apparatus. Serrasalmid dentitions are ubiquitously heterodont, having incisiform and molariform dentitions reminiscent of mammals. Finally, we propose that simultaneous tooth replacement be considered as a synapomorphy for the family.

International audience; The assessment of the date of death (DOD) of animals found in archaeological sites provides insights into the exploitation of their environment by ancient mobile and sedentary populations. In an attempt to overcome the limitations of the traditional methods, we determine the DOD of domestic caprines using sequential oxygen isotope analysis of developing tooth enamel. We built a reference set composed of developing molars from 14 modern sheep and goats from Western and Central Mongolia with known DOD. The teeth were sequentially sampled, and δ 18 O sequences were modelled using a cosine function in order to position the lowermost δ 18 O value (δ f) within the annual cycle. We found that δ f values are strongly linearly correlated with the DOD (R 2 ¼ 0.88), allowing the use of this regression to estimate the DOD with a precision of about �25 d (1σ). This method was applied to determine the DOD of caprines found in two graves in the Xiongnu necropolis of Egiin Gol, Mongolia. We determined a slaughter date of late July and late September for the two graves, respectively, suggesting that burial occurred during the warm season. By combining this information with age at death assessed using tooth eruption stages and tooth wear patterns, we were also able to determine that caprine birth occurred mostly in April and was strongly controlled within this seasonal window by the herders, much like in Mongolia today.

Aim This study aimed to investigate salivary concentrations of Streptococcus mutans (S. mutans) and some Lactobacilli, and plaque index (PI) in patients wearing fixed versus removable orthodontic appliances. Methods A sample of 90 orthodontic patients (56 males and 34 females) was included in the study: 30 subjects (aged 21.5±1.5 years) were treated with removable clear aligners (CA), while for other 30 cases (aged 23.3±1.6 years) a fixed multibrackets appliance (MB) were utilized, and 30 patients (aged 18.2 ±1.5 years) wearied a removable positioner (RP). Salivary concentrations of S. mutans and Lactobacilli and PI were evaluated prior to start of the orthodontic treatment, after 3 months and 6 months. Results After 6 months, 40% of MB patients (12 subjects over 30) showed a concentration of S. mutans associated to high risk of developing tooth decay (CFU/ml>105), differently from participants wearing removable appliances (odds ratio = 5.05; 95% C.I. = 1.72‐14.78; chi‐square = 9.64; p = 0.0019). The same trens was observed for the concentration of Lactobacilli (odds ratio = 4.33; 95% C.I. = 1.53‐12.3; chi‐square = 8.229; p = 0.004). In addition, over the duration of the study, CA patients maintained PI at 0 level, while MB patients experienced a statistically significant increasing trend of PI over time, and their PI became clinically/statistically relevant after 6 months, respect to CA and RP patients. Conclusions Comparing all the data, while, after 6 months, only about 10% of CA patients and 13.3% of RP patients achieved a microbial colonization which may lead to high risk of caries development, about 40% of MB patients ‐ and 20% after 3 months ‐ showed a high level of vulnerability to developing caries, which require additional strategies for plaque control and microbial colonization to be employed.

A case of a 20-year-old female is described in which the premolars and molars on the right side of the arch display altered crown proportions and altered occlusal morphology. There is no evidence of an orofacial congenital disorder or history of trauma. It is argued that the asymmetrical expression of crown form does not fall within the normal range of variation but has resulted from a localized disruption in cellular function within the developing tooth germs, probably upsetting the folding of the internal enamel epithelia. This has produced crowns that have rounded cuspal outlines and reduced intercuspal distances. Superimposed space constraints in the mandible may have also led to compression of the lower molar crowns mesiodistally and affected their root formation.

The transparency of soft tissue in Xenopus laevis tadpoles and the anterior-posterior orientation of their developing tooth germs in the upper jaw offer a unique opportunity for the in vivo charting of the first 15-20 days of the developing dentition. Twenty-two X. laevis tadpoles were anesthetized daily and their mouths opened to record the first appearance, position, and development of tooth germs in the upper jaw. The initiation patterns revealed considerable variability between animals, and even between the jaw quadrants in the same animal. This variability appears within a structural boundary and the results are consistent with the presence of an odontogenic band. The final length of dental rows far exceeded the jaw growth for each quadrant during the recording period. This in vivo investigation underlines the limits of cross-sectional studies, and in particular the assumption that tooth germs initiate at the same position in the dental row. The tooth germ initiation patterns in this study did not align with the predictions of standard models for the development of the dentition-Zahnreihen, Clone, and New Progress Zone theories.

Structured AbstractObjectives Many reports suggest that children with cleft lip and palate (CLP) have delayed dental development and asymmetrical timing of tooth-pair formation. We aimed to investigate the dental maturation of permanent teeth in children with complete unilateral CLP (UCLP) and compare the findings with non-CLP children. Setting and sample population This case-control study used 115 radiographs of children with complete UCLP and controls (non-CLP children matched on age, gender and ethnicity) from a hospital-based dental clinic in Singapore. Material and methods Orthopantomographs of 60 children with complete UCLP (5-9 years old) and 55 children (9-13 years old) from the same cohort were investigated using the Demirjian's method and compared with controls to determine if there were any differences in dental maturation with age. Results Delayed dental maturation was found in the 5- to 9-year-old children with UCLP compared to controls by 0.55 years (standard deviation: 0.75) (P

The developing tooth offers a model for the study of ectodermal appendage organogenesis. The signaling networks that regulate tooth development have been intensively investigated, but how cell biological responses to signaling pathways regulate dental morphogenesis remains an open question. The increasing use of ex vivo imaging techniques has enabled live tracking of cell behaviors over time in high resolution. While recent studies using these techniques have improved our understanding of tooth morphogenesis, important gaps remain that require additional investigation. In addition, some discrepancies have arisen between recent studies, and resolving these will advance our knowledge of tooth development. Developmental Dynamics 246:442-450, 2016. © 2017 Wiley Periodicals, Inc.

Background/aim Pediatric mandibular distal fractures presents unique treatment challenges which are usually managed with open reduction and internal fixation (ORIF) with the risk of developing tooth bud injuries. A conservative management through Maxillo-mandibular fixation (MMF) with orthodontic bracket-elastic as out-patient department (OPD) service has been used for these fractures presenting with derangement of occlusion. The aim of this study was to retrospectively analyze MMF with orthodontic bracket-elastic as a treatment method and its outcome for management of pediatric mandibular distal fractures. Methodology Data of seventeen pediatric cases diagnosed with displaced mandibular distal fractures managed with MMF with orthodontic bracket-elastic over a period of 5 years were analyzed. In this technique, two weeks of immobilization and one week for guiding elastics were used. Results The mean age of patients was 7.6 ± 1.6 years with a mean follow up of 24 months. All fractures healed uneventfully with satisfactory occlusion. The cases included 23.5% minimally displaced, and 64.7% moderately displaced and 11.8% significantly displaced fractures with step deformity with successful remodeling of the lower border contours over a duration of 18 months ±1 month. The developing tooth buds in the fracture line showed no complications except for root dilacerations/malformation (n=3). Conclusion MMF with orthodontic bracket-elastic is a viable and conservative technique for the management of pediatric mandibular distal fractures which need to be verified through randomized trials for generalization of the results.

Mandible is one of the commonly fractured bone in children during maxillofacial trauma. These factures are usually managed conservatively but sometimes require open reduction and internal fixation (ORIF). Management of mandibular fracture in children is influenced by the presence of developing permanent tooth buds, minimal anchorage from primary teeth and facial growth and development. Although, there have been technical and material advancements with ORIF, it is still associated with complications related to growth and damage to developing teeth. This case report describes a case of mandibular parasymphyseal fracture managed successfully with open reduction and internal fixation using a miniplate and a consequent cessation of root growth and eruption failure of a mandibular canine present in the fixation area.

Ultratrace element is a relatively new term, and is defined as those elements with an established, estimated, or suspected dietary requirement of minute amount, generally of the order of µg/day. This chapter focuses on fluorine (F), aluminium (Al), molybdenum (Mo), and cobalt (Co). Whilst diet is the principal source of Al, Mo, and Co found in the body, inadvertent ingestion of dental hygiene products accounts for a significant proportion of F intake. Apart from F, the influence of other ultratrace elements on oral health, and in particular dental caries, has not been fully established. The calcified tissues contain 99% of body F. During tooth development, ingested (systemic) F is incorporated into the apatite crystals of the developing tooth which helps in improving resistance to acid demineralisation. However, the presence of low but constant levels of topical F in the fluid phase at the tooth enamel surface are more important in controlling tooth decay in people of all ages. An adequate intake, from all dietary and non-dietary sources, is estimated as 0.05 mg/kg body weight/day for children older than 6 months and adults, based on estimated intakes that have been shown to reduce the incidence of dental caries while minimising adverse health effects such as dental fluorosis. An inverse relationship between incidence of dental caries and levels of Al in drinking water, food, and soils has been indicated by some epidemiological studies. Co and Mo, whilst occasionally showing potential beneficial oral health effects in laboratory experiments, do so at concentrations much higher than found in vivo.

Avascular osseo-necrosis is one of the rare complications that has never been reported in pediatric mandibular distraction. However extensive periosteal stripping, developing tooth buds and aberrations related to the inferior alveolar canal in malformed syndromic mandible may lead to compromised vascularity to the osteotomised segments leading to avascular necrosis after monofocal mandibular distraction. The aim of the current case report is to describe this rare complication after pediatric MMDO and discuss in detail the possible etio-pathologic mechanisms and provide an insight for the management strategies.

Dentigerous cysts are developmental odontogenic cysts and are always associated with an unerupted or developing tooth bud. Mesiodens is a supernumerary tooth found in the anterior maxilla. Supernumerary teeth seldom associate with dentigerous cysts and dentigerous cysts around supernumerary teeth account for 5% of all dentigerous cysts. Here we report a case of dentigerous cyst in association with a mesiodens in an 8 year old boy. The cyst was treated by enucleation with minimal tissue trauma and nerve preservation.

Infant oral mutilation is the practice of removing developing tooth germs, commonly the mandibular canine, in infants up to the age of 1 year. Subsequent complications include missing, impacted or hypoplastic permanent anterior and canine teeth. We report on a case of bilaterally missing lower canines thought to be due to infant oral mutilation. It is important that general dental practitioners are aware of this practice and resulting complications when treating families from sub-Saharan East Africa.

Dental fluorosis is a chronic fluoride –induced condition in which an excess of fluoride is incorporated in the developing tooth enamel...

Background Tooth development involves epithelial–mesenchymal interactions, and its molecular mechanisms have been elucidated in various studies of growth factor signaling. However, there are discordances between the inferred molecular mechanisms and histological observations of shape changes of the growing tooth germ. To clarify the mechanisms of tooth morphogenesis, direct observations of cell dynamics are essential. Highlight A technique for direct observations of cell dynamics and morphological changes in the developing tooth germ has not been developed. Here, we present our observations of cell dynamics during tooth morphogenesis and review new imaging techniques used in recent studies. We also describe the importance of live imaging and its potential applications in the field. Conclusion Time-lapse imaging is a useful tool for understanding cell movement and cell lineages, and will contribute the elucidation of the mechanisms of tooth development.

Early in the twentieth century, biology was seen as grounded in the dual foundations of cells and evolution. Cells provided the most basic living unit, and evolution provided a way for cells to become established in different organisms. However, as the twentieth century progressed, cells and cellular level phenomena became embedded in different research traditions within developmental biology with varying connections to an evolutionary framework. While researchers focusing on differentiation could continue to link their research to evolution through heredity, those focused on morphogenesis largely gave up any evolutionary perspective. Morphogenetic research programs continued, without evolution, until late into the twentieth century, when fruitful new insights brought development back into the process of evolution. This chapter takes teeth as an exemplary case study for these changes with special focus on the enamel knot, now thought of as the morphogenetic control center of the developing tooth. Once development, and especially cellular level phenomena, was seen in the light of evolution, the enamel knot became the central component of a new paradigm in evolutionary developmental biology—one that, to this day, continues to provide a means of understanding the development and evolution of teeth. The intersection of cells and “the Darwinian tradition” is a complex relationship. This chapter offers an alternative history of the ways in which development, evolution, and cells were brought together throughout the twentieth century and challenges the common conception that genes are the sole locus of explanation for research at the intersection of development and evolution.

Myxomas of the jaws are considered to arise from odontogenicectomesenchyme. They bear a close resemblance to the mesenchymalportion of a developing tooth. Peripheral odontogenic myxomas are veryrare and less aggressive compared with the central odontogenic myxomas.No case of peripheral odontogenic myxoma with calcification has beenreported to date. The purpose of this article is to document a case ofperipheralodontogenicmyxomawithcalcification,locatedontheposteriormaxillarygingiva. Clinicalrelevance Odontogenicmyxoma(OM)isararebenigntumourofthe jaws characterised by accumulation of mucoidground substance with little collagen. Peripheral OMs,although considered to be less aggressive than theircentral counterpart, if left untreated have unlimitedgrowth potential. The odontogenic origin of theselesions is also controversial and hence discussed in thisarticle. Introduction Myxomas are relatively rare benign tumours ofmesenchymal origin and can occur in various sites inthe body including the skin and subcutaneous tissue,heart (mainly in the left atrium), and also in varioussites of the head and neck

Fusion may be defined as a union of two separately developing tooth germs typically leading to one les s tooth than normal in the affected arch. This phenomenon has been described by several different terms, such as ge mination, double teeth and twinning. Factors which have been implicated as possible etiologies for fused teeth i nclude hypervitaminosis, pressure from physical contact of young tooth buds, and genetic factors. This articl e reports two cases of unilateral fused primary maxillary incisor s in siblings, with a discussion covering further e laboration of definitions of gemination and fusion, clinical impl ementation and review of literature.

The mandibular second premolar is highly variable developmentally. Agenesis, abnormal tooth germ position, distal inclination of the developing tooth, and impaction are among the reported developmental anomalies. Detection of pathologic lesions associated with an impacted tooth usually requires removal of the tooth and the lesion. The purpose of the present report was to describe the radiographic and histopathologic features of a case of pericoronal radiolucency associated with an impacted mandibular premolar tooth.

The developing tooth can be regarded as a typical vertebrate organ starting as an epithelial bud that subsequently develops into a mature organ, a process that entails extensive epithelial-mesenchymal interactions. Functions of various signaling molecules and gene expression during odontogenesis have appealed considerable interest. Although it now is evident that microRNAs (miRNAs) are implicated in tooth development, their regulative role remains essentially unknown. MicroRNAs have been studied in the context of most ectodermal organs but only a few functional studies of their role in tooth development have been published so far. The fine-tuning of this epithelial-mesenchymal network via the

Looking in microscopic detail at the 3D organization of initiating teeth within the embryonic jaw has long-proved technologically challenging because of the radio-translucency of these tiny un-mineralized oral tissues. Yet 3D image data showing changes in the physical relationships among developing tooth and jaw tissues are vital to understand the coordinated morphogenesis of vertebrate teeth and jaws as an animal grows and as species evolve. Here, we present a new synchrotron-based scanning solution to image odontogenesis in 3D and in histological detail using a silver-based contrast agent. We stained fixed, intact wild-type mice aged embryonic (E) day 10 to birth with 1% Protargol-S at 37°C for 12-32 hr. Specimens were scanned at 4-10 µm pixel size at 28 keV, just above the silver K-edge, using micro-computed tomography (µCT) at the Canadian Light Source synchrotron. Synchrotron µCT scans of silver-stained embryos showed even the earliest visible stages of tooth initiation, as well as many other tissue types and structures, in histological detail. Silver stain penetration was optimal for imaging structures in intact embryos E15 and younger. This silver stain method offers a powerful yet straightforward approach to visualize at high-resolution and in 3D the earliest stages of odontogenesis in situ, and demonstrates the important of studying the tooth organ in all three planes of view.

Programmed cell death or apoptosis is considered a vital component of various processes including normal cell turnover, proper development and functioning of the immune system, hormone-dependent atrophy, embryonic development, and chemical-induced cell death. Inappropriate apoptosis (either too little or too much) is a factor in many human conditions including neurodegenerative diseases, ischemic damage, autoimmune disorders, and many types of cancers. The process of apoptosis is generally characterized by distinct morphological characteristics and energy-dependent biochemical mechanisms. An understanding of its role in the pathophysiology of oral tissues is pertinent to the development of novel therapeutic approaches. The developing tooth passes through the various morphologic stages and apoptosis is observed selectively in certain locations. This review focuses on the current knowledge of apoptosis emphasizing its role in normal oral tissues and odontogenesis.

Amongst the cysts of the jaw dentigerous cyst (DC) is one of the most prevalent types of odontogenic cysts, which is associated with the crown of an unerupted or developing tooth. DC is more commonly seen with mandibular third molar and maxillary canine and rarely other teeth are involved. These cysts seldom associate with supernumerary teeth. The purpose of this article is to describe a case of large dentigerous cyst associated with supernumerary teeth and an ectopic canine, which is a rare presentation along with its management.Key words: Dentigerous cyst, ectopic teeth, supernumerary teeth

Cleft lip and palate (CLP) is the most common craniofacial abnormality and the fourth most common birth defect in Singapore. Many reports suggest that CLP children have delayed dental development and asymmetrical timing of tooth-pair formation. The aim of this study was to investigate the timing of development of permanent teeth in unilateral CLP (UCLP) children and to compare the findings with non-CLP children in Singapore. A total of 60 UCLP children aged between 5 and 9 years (mean 6.64 ± 0.90 years) and a non-CLP control group matched for age, gender, and race were investigated and compared. Dental records and radiographs were studied and the dental maturation was determined using the Demirjian's method (1973). The dental maturation of UCLP children were delayed compared with non-CLP children by a mean of 0.55 ± 0.75 years and the delay was statistically significant (P < 0.001). The UCLP group also had significantly higher risk of asymmetrically developing tooth pairs than the control group (P < 0.001). The most commonly delayed tooth in development was the maxillary cleft-sided lateral incisor. In conclusion, the UCLP children in Singapore demonstrated delayed dental maturation and a higher occurrence of asymmetrical tooth-pair formation than the non-CLP children.

Currently, plastic gear is widely used as parts of office equipment and industrial machines, because plastic substance has an advantage of light weight and possible to operate in oil-fewer conditions. However, under cyclic loadings, their occurred repetitive deformation due to weak tensile strength and bending stress rather than metal gear. Furthermore, they have a problem of attrition and breakage owing to frictional heat. For solving these problems, when plastic gear`s opponents are metal gear, we should design that plastic gear`s tooth be thick and metal gear`s tooth be thin. In this research, we developed the program which developing tooth profile of non-standard gears automatically and calculating over-pin diameter for inspection after making gear.

Introduction Endodontic infection or physical trauma of a developing tooth might lead to unusual situation for root development. Methods Two cases are presented. Both cases involved immature mandibular second premolars with infected pulps. In the first case, the tooth was treated by apexification, whereas revascularization procedures were performed in the second case. Interestingly, a separated root tip was observed with the main root at the initial presentation of case 2. Results At recall after apexification, a separate root tip was observed apically to the main root end, and root development continued in case 1. In the second case, the separate root displayed continuing root formation, but the main root did not gain root thickness or length. Conclusions These cases revealed that Hertwig’s epithelial root sheath and stem cells from the apical papilla can be separated from the main tooth structure by an external force or iatrogenic factors and thereafter produce a separate root tip.

Myxomas of the jaws are believed to arise from odontogenic ectomesenchyme. They bear a close resemblance to the mesenchymal portion of a developing tooth. Myxomas are predominantly found in young adults. Radiographically myxomas appear as unilocular or multilocular radiolucencies. The radiolucent defect can contain thin, wispy trabeculae of residual bone which are often arranged at right angles to each other. Recurrence rates from various studies average approximately 25%. We report two cases of odontogenic myxoma, occurring in a 27-year-old female patient and 45-year-old male patient with clinical and radiographic findings and a brief review of literature.

Dentigerous cysts are benign odontogenic cysts that arise from the dental follicle of an unerupted or developing tooth. They are the second most common odontogenic cysts after radicular cysts. Multiple dentigerous cysts have been reported on occasion in association with syndromes such as cleidocranial dysplasia, mucopolysaccharidosis and basal cell nevus syndrome. We report the clinical and radiologic findings of bilateral maxillary dentigerous cysts in a nonsyndromic 10-year-old boy, a condition that, to our knowledge has only been reported twice. The importance of early diagnosis and management is highlighted.

Background The authors investigated the postcementation sensitivity associated with self-adhesive resin cements used with fixed partial dentures (FPDs). Methods The authors recruited 20 patients who needed posterior porcelain-fused-to-metal FPDs and divided them randomly into three groups. They prepared 50 abutments, then cemented FPDs with one of two self-adhesive resin cements (Breeze Self-Adhesive Resin Cement, Pentron Clinical Technologies, Wallingford, Conn., and RelyX Unicem Self-Adhesive Universal Resin Cement, 3M ESPE, Seefeld, Germany) or an etch-and-rinse resin cement (RelyX ARC Adhesive Resin Cement, 3M ESPE, St. Paul, Minn.). The authors measured participants' tooth sensitivity to cold water, air blast and biting at 24 hours and at two, six and 12 weeks after FPD cementation by using a continuous visual analog scale (VAS). Data were analyzed statistically by means of the Mann-Whitney test. Results For cold tests, the highest VAS scores occurred 24 hours after cementation. The mean VAS scores associated with RelyX ARC were significantly higher than those associated with Breeze and RelyX Unicem ( P P > .05). With all cements, sensitivity to cold decreased significantly after two to six weeks; however, with RelyX ARC, VAS scores stayed above the 30 percent level even after 12 weeks. The biting sensitivity associated with RelyX ARC was significantly higher than that associated with Breeze and RelyX Unicem ( P Conclusions and Clinical Implications Breeze and RelyX Unicem were associated with significantly lower postoperative tooth sensitivity values than was RelyX ARC. With Breeze and RelyX Unicem, postoperative tooth sensitivity disappeared after two to six weeks; however, with RelyX ARC it remained even after 12 weeks. Clinicians may use self-adhesive resin cements, and benefit from their bonding potential, without fear of patients' developing tooth sensitivity.

Introduction: Primordial odontogenic tumors are a rare recently described mixed odontogenic tumor composed histopathologically of dental papilla like tissue and enamel organ like tissue. Only nine cases have been documented worldwide and we are reporting the tenth case which is from Egypt. Clinical finding: A 2-year-old Egyptian boy that presented with an asymptomatic swelling of the mandible which appeared with multilocular radiolucency associated with an impacted developing tooth on a computerized tomography (CT) scan. Diagnoses, interventions, and outcomes: The lesion was excised and diagnosed as a primordial odontogenic tumor. The patient was followed up for two years with no recurrence. Conclusion: Differentiation of primordial odontogenic tumors from other odontogenic tumors, which resemble it histopathologically is crucial to avoid unnecessary aggressive treatment.

The fate of developing tooth buds located in relation to mandibular fractures was investigated in three infancy cases. Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up.

Objective This study examined the expression pattern of the Deleted-in-colorectal-carcinoma (DCC) gene in developing rat tooth germs. Methods Rat pups at 4, 7 and 10 d postpartum were used in this study. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescent localization were used to determine the level of DCC expression during tooth development. Results There was more than 2-fold higher level of DCC mRNA in the rat 2nd maxillary molar tooth germs on 10 d postpartum, which was the root stage, than in the rat 3rd maxillary molar tooth germ, which was at the cap/early bell development stage. In addition, the levels of DCC mRNA in the 2nd maxillary molar germs at 4, 7 and 10 d postpartum increased gradually according to tooth development. Interestingly, immunoreactivity against DCC was specifically detected in the differentiating ameloblasts. DCC was observed in the lateral and apical sides of the newly differentiating and secretory stage ameloblasts. Afterwards, DCC was localized only in the apical side of the maturation stage ameloblasts, not in the lateral side. Conclusion DCC is expressed in the differentiating ameloblasts, which suggests that this molecule plays a crucial role in amelogenesis.

Melanotic neuroectodermal tumor of infancy (MNTI) is an uncommon, fast-growing, pigmented neoplasm of neural crest origin. It primarily affects the maxilla of the infants during the first year of life. Approximately, a few hundred of these tumors have been reported in medical literature. We present a case of a newborn with MNTI involving the anterior maxillary region. The treatment included surgical excision of the lesion with safe margins, using an intraoral approach and removal of associated developing tooth buds. We made no attempt at immediate bone grafting. The patient had no recurrence at 1 year postoperatively. The diagnostic features and management alternatives of MNTI are discussed.

Periodontal disease is an infectious disease affecting the supporting tissue of the teeth, periodontium. The main purpose in the treating periodontal disease is removal of plaque, which is a mass of bacterial accumulation on the tooth surface and is the cause of the disorder, and to prevent re-infection by controlling the supra-gingival plaque that was its origin. As a result of the findings of Jan Lindhe's research group and other Scandinavian researchers, a Scandinavian approach to periodontal therapy has developed, based on non-surgical therapy or restricted surgical indications, scrupulous plaque control and use of antiseptics and antibiotics. Main aim of the treatment is to stop the progression of the disease. This was accomplished in the middle of 80s. Since the late 80s there has been a paradigm shift in the purpose of the periodontal treatment from prevention of infection toward regeneration of the lost periodontium. The first biologically oriented approach is the Guided Tissue Regeneration technique, which was developed by the Gothenburg Univ. group consisted of Drs. Jan Lindhe, Sture Nyman and Thorklid Karring. The second generation of regeneration procedure is Emdogain® therapy based on the biologic process of developing tooth roots and their supporting tissues. The technique was introduced from Sweden and well accepted. Recently, dental implants, which have been used in edentulous jaws, have been applied to partially absent teeth, and its utility has been confirmed. Sometimes the removal of several teeth cannot be avoided in patients with severe periodontal disease. In such cases implants have begun to be used to restore lost oral cavity function.

The human tooth with immature apex is a developing organ available for investigation. In this tooth, especially in the apical pulp, the proliferation and differentiation of various cells are activated to make a complete tooth. We investigated the notion that unique cells are included in the apical pulp of human tooth with immature apex. Human impacted third molars with immature apex freshly extracted for orthodontic reasons or treatment were obtained. Histological analyses revealed that BrdU-incorporating cells and cells positive for the mesenchymal stem cell markers SH2 and SH3 were located in the same region. The cells from the apical pulp of a human tooth with immature apex, designated here as apical pulp-derived cells (APDCs), can be cultured easily in vitro under ordinary serum-supplemented culture condition. The expression of surface markers of expanded APDCs is similar to that of bone marrow mesenchymal stem cells, except for CD49d (α4-integrin). APDCs differentiated into mineralized cells, adipocytes, chondroblasts and neural cells in vitro . APDCs have a high capacity for proliferation and multilineage potential in vitro . Our results indicate that human tooth with immature apex is a precious tissue source for the research of human adult stem cells and for the advancement of dental and regenerative medicine.

Innervation plays a key role in the development, homeostasis and regeneration of organs and tissues. However, the mechanisms underlying these phenomena are not well understood yet. In particular, the role of innervation in tooth development and regeneration is neglected. Several in vivo studies have provided important information about the patterns of innervation of dental tissues during development and repair processes of various animal models. However, most of these approaches are not optimal to highlight the molecular basis of the interactions between nerve fibres and target organs and tissues. Co-cultures constitute a valuable method to investigate and manipulate the interactions between nerve fibres and teeth in a controlled and isolated environment. In the last decades, conventional co-cultures using the same culture medium have been performed for very short periods (e.g., two days) to investigate the attractive or repulsive effects of developing oral and dental tissues on sensory nerve fibres. However, extension of the culture period is required to investigate the effects of innervation on tooth morphogenesis and cytodifferentiation. Microfluidics systems allow co-cultures of neurons and different cell types in their appropriate culture media. We have recently demonstrated that trigeminal ganglia (TG) and teeth are able to survive for a long period of time when co-cultured in microfluidic devices, and that they maintain in these conditions the same innervation pattern that they show in vivo. On this basis, we describe how to isolate and co-culture developing trigeminal ganglia and tooth germs in a microfluidic co-culture system.This protocol describes a simple and flexible way to co-culture ganglia/nerves and target tissues and to study the roles of specific molecules on such interactions in a controlled and isolated environment.

Objective: Trauma to the oro-facial structures in children is different from trauma in adults. There are several points of differentiation between the two, the most important being growth. Aim: The purpose of this paper is to present the advantages of a vacuum-formed splint which was chosen as a practical and effective conservative treatment approach for the management of maxillofacial trauma. Case Report: A 9-year old boy reported to the department of pediatric and preventive dentistry with right mandibular parasymphyseal fracture. The trauma presented with the unique challenge to save and support the unerupted and developing tooth buds. Therefore, a vacuum-formed splint was fabricated and cemented in place for the next 4 weeks. Conclusion: The splinting method used for stabilization of the injured teeth is an important issue in trauma therapy to support the periodontal healing. Pediatric maxillofacial traumas require different clinical treatment strategies compared with fractures of the adult population.

— Trauma to primary teeth may result in direct damage to underlying developing permanent teeth because of the close relationship that exists between the apices of the primary teeth and their permanent successors. Injuries to developing teeth have been classified into ten different categories, using a classification that is largely based on developmental alterations to the permanent teeth. However, this classification does not include other types of trauma that may occur to developing teeth, such as crown fractures. Although apparently rare, such injuries can occur by direct contact of the impacting object with a developing tooth, as illustrated by the following case report.

Ameloblastoma is a rare odontogenic tumor with characteristics of epithelial tissue that produces enamel for the developing tooth. This lesion is generally considered benign, but has malignant forms that invade locally and metastasize. We present a 60-year-old man with maxillary ameloblastoma that after multiple recurrences developed intracranial extension with dural involvement of the middle cranial fossa and was treated by endoscopic transnasal resection followed by radiation therapy. Our technique and intraoperative findings are described with a review of the literature on intracranial ameloblastoma. This patient represents a unique account of endoscopic transnasal resection being utilized in the treatment of intracranial extension of ameloblastoma and demonstrates potential for application in similar cases.

In the developing tooth, the bisphosphonate HEBP causes hypoplasias and hypomineralization of the enamel and dentine as well as inhibition of acellular cementum formation. Here, we describe a novel effect, associated with dentine mineralization. HEBP was administrated to young rats, and the maxillary molars were analyzed histologically. Localized dentinal nodules, protruding towards the pulp, were found in the developing crown of the molars. They occurred in regions, where the mantle dentine was about to mineralize at the time of the injection, and were more frequent at the mesial cusp side. The nodules accumulated mineral, as evidenced by the fluorescence after calcein and tetracyclin labelling. Histologically, the nodules were separated from the enamel by a layer of mantle dentine and were progressively surrounded by predentine and dentine. The nodules were interpreted to contain transport or metabolism intermediates, which were locally accumulated due to the interruption of the mineralization process by HEBP.

Intrusion in a developing permanent tooth is an extremely complicated traumatic injury and is rarely seen in the permanent dentition. The damage caused by the trauma to the surrounding tooth structures results in a multitude of complications during the healing process. Careful repositioning of the intruded tooth by orthodontic means, revascularisation of the immature tooth to regain vitality, and periodontal treatment to provide the most acceptable aesthetic outcome are described in this case report. It outlines the treatment options to overcome the complications and variable outcomes. The present report emphasises the importance of a multidisciplinary approach to provide complete rehabilitation of a traumatically intruded developing tooth.

Ameloblastoma is the most frequent odontogenic tumor arising from dental epithelium. It is characterized by its histological resemblance to the enamel organ of the developing tooth germ; but enamel formation is not observed. Acanthomatous ameloblastoma is considered an aggressive odontogenic tumor characterized by irregular verrucous masses adjacent to the tooth, consisting of sheets of keratinizing odontogenic epithelium. Here we are reporting a case of 35-year-old male with swelling on left body of the mandible region which was diagnosed as acanthomatous ameloblastoma based on clinical, radiographic and histopathological features.