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A comparison of two different bone-harvesting techniques for secondary alveolar bone grafting in patients with cleft lip and palate.

OBJECTIVE: To compare the outcome of the trephine with open hip surgery for alveolar bone grafting in cleft lip and palate surgery. DESIGN: The study was retrospective. The radiographs were assessed blindly and on two separate occasions 1 week apart. SETTING: University Teaching Hospital. PATIENTS, PARTICIPANTS: In one group (group A), a trephine was used; in the other (group B), open hip surgery was employed. Group A was comprised of 16 patients (nine with unilateral and seven with bilateral clefts of the lip and palate) and group B, 13 patients (eight unilateral and five bilateral). The prime entry criterion for inclusion in the study was that the canine tooth had erupted into the graft site. INTERVENTIONS: A long cone periapical radiograph was taken of the erupted canine tooth in the graft site. MAIN OUTCOME MEASURE: The radiographs were graded from type I to type IV, as described by Bergland et al. (1986a). A comparison was also made of the eruption of the canine, postoperative morbidity, and length of stay in hospital for each group. RESULTS: There was no statistically significant difference in the interdental bone height (p=.61, Mann-Whitney U test). In group A, all patients had a satisfactory clinical outcome (type I or II), and in group B, only one patient had an unsatisfactory result (type III). The spontaneous eruption of the canine and the number of nights spent in the hospital were also similar for both groups. However, no patients in group A suffered postoperative complications, whereas three patients in group B reported either a limp or postoperative infection of the hip. CONCLUSION: Both techniques produced satisfactory repair of the bony defect, but the open hip surgery resulted in greater postoperative morbidity.

Adolescent↗

[Extended fissure sealing--a review for the dental practitioner].

There is scientific proof that destructive processes of the oral cavity can be avoided through a combination of general prophylaxis with individual preventive care. In children with few or no carious lesions in the deciduous dentition a complete eradication of caries of the permanent teeth should definitely be attempted. Pits and fissures of premolars and molars should therefore be individually sealed within six months after tooth eruption. In cases of incipient occlusal caries preventive resin restorations allow the repair with a minimum of tooth removal, i.e. therapeutic preventive dentistry. The use of the somewhat destructive conventional restorative techniques including prophylactic odontotomy, fissure eradication and extension for prevention that are unfortunately favored by the common dental fee policy should be strictly limited to cases where better alternatives are as yet unpracticable.

Child↗

[Osteopetrosis. Classification, etiology, treatment options and implications for oral health].

Bone is continuously remodelled to maintain its strength and structural integrity. Remodelling is the result of an equilibrium between bone formation performed by osteoblasts and bone resorption performed by osteoclasts. In osteopetrosis this equilibrium is disturbed by a defect in the osteoclastogenesis or by disfunction of osteoclasts. Osteopetrosis is divided into four types: malignant infantile osteopetrosis, intermediate osteopetrosis, and two types of autosomal osteopetrosis. Malignant infantile osteopetrosis is usually diagnosed within the first year of birth by bone sclerosis and bone marrow obliteration. This type is very severe and usually results in death within a few years. The intermediate type usually appears before the age of ten and leads to recurrent pathologic fractures and cranial nerve compression. Autosomal dominant osteopetrosis is usually mild and consists of two sybtypes. Type I involves marked thickening of the cranial vault. Type II patients have predominantly sclerosis of the pelvis, the vertebrae and the base of the skull. Type I and II patients may often be long-lasting asymptomatic, but will eventually present with pathologic fractures, bone pain, and the effects of cranial nerve compression. Oral problems of osteopetrosis are delayed tooth eruption, absence of some teeth, malformed teeth, enamel hypoplasia, disturbed dentinogenesis, hypomineralisation of enamel and dentin, propensity for tooth decay, defects of the periodontal membrane, thickened lamina dura, mandibular protrusion, and the presence of odontomas. Tooth removal should be limited as it may induce bone fractures and osteomyelitis.

Bone Resorption↗

Malignant infantile osteopetrosis: dental effects in paediatric patients. Case reports.

AIM: Malignant Infantile Osteopetrosis is a hereditary pathology caused due to osteoclastic cells which are incapable of carrying out their functions and hence do not resorb osseous tissue where required. Thus the consequence is that during growth phase, the medullary cavities and nervous tissue cavities do not undergo sufficient growth and the corresponding organs do not develop adequately. The aim of this study is to outline the role of the pediatric dentist who has to carry out protocols of primary, secondary, tertiary prevention intervening at many levels. Clinical features and dental effects are described. Two case reports are presented in this study. CONCLUSION: Oral problems of osteopetrosis are delayed tooth eruption, absence of some teeth, malformed teeth, enamel hypoplasia, disturbed dentinogenesis, hypomineralisation of enamel and dentin, propensity for tooth decay, defects of the periodontal membrane, thickened lamina dura, mandibular protrusion, and the presence of odontomas. Tooth removal should be limited as it may induce bone fractures and osteomyelitis. The role of the pediatric dentist is defined.

Bone Marrow Transplantation↗

Forced eruption combined with gingival fiberotomy. A technique for clinical crown lengthening.

A new approach to clinical crown lengthening has been developed and described. The technique combines controlled eruptive tooth movement and incision of the supracrestal gingival attachment. The procedure was performed in patients with severe destruction of a tooth crown and in whom clinical crown lengthening procedures were essential before the teeth could be properly restored. Controlled eruptive forces were activated by simple orthodontic appliances. During the active phase of forced eruption, repeated intrasulcular incisions through the junctional epithelium and the supracrestal connective tissue attachment were performed. The technique prevented coronal displacement of the gingiva and the attachment apparatus during the orthodontic extrusion, thus overcoming the need for corrective osseous surgery.

Adolescent↗

Mechanical responses of the periodontal ligament in the transverse section of the rat mandibular incisor at various velocities of loading in vitro.

Stress-strain curves of the periodontal ligament (PDL) were obtained at various velocities of extrusive loading of 1, 10, 10(2), 10(3) and 10(4) mm/24 h in vitro. Significant increases of the maximum shear stress, tangent modulus and failure strain energy density were found with increases in the velocity of loading. The maximum shear strain increased from a velocity of 1 to 10 mm/24 h but decreased from 10 to 10(4) mm/24 h. It was shown histologically that the free surface of the PDL adhering to the cementum after mechanical testing was rough and irregular at higher velocities and rather smooth at lower velocities. These results showed that the mechanical properties and mode of failure of the rat incisor PDL were greatly dependent on the strain rate. It is possible that the PDL of the continuously erupting rat incisor has mechanical characteristics favourable for resisting weakly to slow and small eruptive forces but strongly to the fast and large occlusal forces as suggested previously [Chiba and Komatsu, The Biological Mechanisms of Tooth Eruption and Root Resorption (1988)].

Alveolar Process↗

Enamel hypomineralization viewed from the pattern of progressive mineralization of human and monkey developing enamel.

Microradiograms and their computer-aided image analysis of ground sections of the developing enamel of human permanent third molars and monkey permanent teeth (Macaca fuscata) indicate that the mode of progressive mineralization of enamel is completely different between the matrix formation and maturation stages. During the former stage, the enamel matrix is slightly mineralized. During the latter stage, which takes a much longer period than the previous stage, the increase in the secondary mineralization takes place first slightly, from the surface toward the inner layer, and then heavily, from the inner layer toward the surface. The narrow outer layer mineralizes very slowly during the middle and late stages of maturation, but finally achieves the highest mineralization of the entire enamel layer. The very narrow innermost layer mineralizes slowly without expanding its width. The former three processes seem to be under the direct control of the ameloblasts. Hypoplastic areas which appear during the matrix formation stages are not necessarily accompanied by hypomineralization. Dysfunction of the cells immediately after the completion of matrix formation appears to cause hypomineralization throughout the entire width of matrix except for the innermost layer. Disorders of the cells occurring during the middle and/or the late stage of maturation--due to chronic metabolic disturbances, such as fluorosis--induced hypomineralization localized mainly at the outer layer. The hypomineralized enamel is not necessarily accompanied by hypoplasia. The process of enamel mineralization is not necessarily fully synchronized with that of tooth eruption. Therefore, the narrow outer layer, especially in the fissure and cervical regions, is sometimes hypomineralized even after the teeth have erupted normally.

Animals↗

[The osteoplastic care of the cleft jaw--an advance for the orthodontic treatment of cleft patients?].

This survey deals with problems of osteoplastic supply of the cleft from the orthodontic point of view. Remarkable parallels exist between primary and secondary osteoplasty: The involution stability of the alveolar process is only presented in a space-less tooth line. Therefore, the primary goal is to guarantee tooth eruption in the former cleft area. However, the antalogous bone graft in the former cleft area has to have a similar structure as adjacent alveolar bone. If tooth germs pass through the bone graft, an own parodont can be built up in the course of eruption. This is applicable to both dentitions. Accordingly, the osteoplasty of clefts is the most important prerequisite for stable treatment results and a healthy dentition.

Bone Transplantation↗

Possible effect of medically administered antibiotics on the mutans streptococci: implications for reduction in decay.

The decline in dental caries in children in North America, Scandinavia, Britain, Ireland and many Commonwealth nations is well documented. The multiple uses of fluoride can account for most, but not all, of this reduction. In this investigation, data are provided which suggest a relationship between antibiotic usage for medical purposes and a decline in both mutans streptococci (MS) and caries. Children attending Grades 1 and 2 in the Coldwater, Michigan school system and who reportedly never received antibiotics had significantly higher proportions of MS in the fissure plaques of first molars than subjects who received antibiotics. The level of decay in the primary dentition was inversely related to the reported usage of antibiotics. The frequent usage of antibiotics could reduce the incidence of dental caries by delaying the colonization of the teeth by the MS. This was evaluated by a prospective study in infants to determine what effect reported antibiotic usage would have on the colonization of newly erupting primary teeth. Only 2 of 10 infants cultured at 2 to 3 week intervals for periods up to 1 year after tooth eruption became colonized by the MS. One had never received antibiotics and the second had been on antibiotics for a single 5-day period. Seven of the 8 non-colonized infants had received antibiotic therapy for periods ranging from 10 to 181 days. Both the Coldwater study and the prospective study of infants suggested a relation between frequency of antibiotic usage for medical purposes and the MS levels on the teeth.

Anti-Bacterial Agents↗

Scanning electron microscopy study of dental enamel surface exposed to 35% hydrogen peroxide: alone, with saliva, and with 10% carbamide peroxide.

Several vital bleaching systems have been introduced in response to the demand in esthetic dentistry. The active agents are commonly hydrogen peroxide or carbamide peroxide used in at-home or in-office techniques. Although generally positive results have been reported concerning the whitening ability of these agents, concerns still remain as to their effects on dental tissues. The purpose of this investigation was to evaluate the effect of these bleaching agents on the enamel surface morphology. Twelve extracted teeth were used according to three experimental protocols. In experimental protocol 1, specimens were treated with 35% hydrogen peroxide. In experimental protocol 2, after treatment with 35% hydrogen peroxide the specimens were immersed in natural saliva for 1 week. In experimental protocol 3, 35% hydrogen peroxide was applied once and 10% carbamide peroxide was applied for 1 week (12 h of 10% carbamide peroxide alternating with 12 h saliva). Scanning electron microscopy evaluation revealed that regional variation in tooth morphology surface sometimes exceeded the effects of the peroxide used according to experimental protocols. Thirty-five percent hydrogen peroxide had a tendency to promote an increase in density of pits. Precipitates were observed on specimen surfaces immersed in natural saliva according to protocol 2. A smooth and shiny surface was observed in specimens treated according to protocol 3. The potential relationship between surface alterations and differences in enamel permeability is currently under investigation. CLINICAL SIGNIFICANCE The differences in various articles written on the subject cannot be reconciled because of the lac of standardization of baseline data regarding factors such as location on the tooth, type of tooth eruption or noneruption, and age in the oral cavity. This article demonstrates that, despite changes observed in the enamel surface after bleaching, normal variation in tooth morphology may exceed the effects of 35% hydrogen peroxide and 10% carbamide peroxide on the teeth. Hence, considering the morphologic features of the tooth surface, bleaching, as described in thi study, can be considered safe for enamel.

Adult↗

Patterns of phenotypic expression of human junctional, gingival and reduced enamel epithelia in vivo and in vitro.

Epithelia differ regionally in their patterns of phenotypic expression. The junctional epithelium (JE) that attaches the oral mucosa to the teeth is a unique tissue that shows a pattern of differentiation unlike other oral epithelia and forms basal lamina against the non-vital tooth surface. The mechanisms that establish this unusual phenotype and the developmental origin of this epithelium are both uncertain. The formation of JE by downgrowth of the oral gingival epithelium (OGE) during tooth eruption has been suggested but morphological studies indicate that it may be derived from the reduced enamel epithelium (REE) that covers the crown of the unerupted tooth. These epithelia of potential origin differ in their developmental histories: intrinsic differences between them could thus significantly influence the phenotype of an epithelium formed from them. The patterns of phenotypic expression of specimens of dissected JE, OGE and REE, and of cell cultures of these epithelia grown under standardized conditions, were examined (1) by immunocytochemistry using monoclonal antibodies with specificity for individual cytokeratins, vimentin and ICAM-1, and (2) by two-dimensional SDS-PAGE and immunoblotting. The results indicated that, in vivo, OGE expressed keratin markers typical of differentiating mucosal epithelium; JE and REE, in contrast, lacked expression of most such markers but expressed keratins typical of simple epithelia together with some undefined keratin peptides. All epithelia showed changes in vitro but OGE remained different from JE and REE. OGE lost expression of the differentiation markers K1, K10 and K13; it acquired some expression of K19, but less than JE and REE. Cultures of JE and REE retained some expression of ICAM-1 and K8 and K18, and consistently acquired high levels of vimentin expression. These findings indicate that differences persist in standardized culture conditions and that these are apparently of an intrinsic nature. They support a concept of the origins of JE from REE and suggest that the unusual in vivo phenotype of JE results partly from intrinsic differences acquired during its development.

Cell Differentiation↗

Evaluation of a new radiographic technique: diagnostic accuracy for mandibular third molars.

OBJECTIVE: To compare the accuracy of Scanora with that of traditional panoramic and intra-oral radiography for the assessment of impacted mandibular third molars. METHODS: Two hundred and fifty-four patients referred for removal of impacted or partly erupted third molars were randomly allocated to one of two groups; 133 were examined by the Scanora system and 121 by a panoramic plus a series of three intra-oral radiographs. The radiographs were read by a trained oral radiologist and her diagnoses validated against the surgeons' findings at operation. RESULTS: There was agreement about the state of tooth eruption in 71.4% of Scanora and 74.4% of conventional examinations and about tooth position in 77.2 and 69.7% respectively (P < 0.05). The number of roots was assessed more accurately by Scanora (82.7% agreement) than by conventional (71% agreement) examination (P < 0.05). There was agreement about the root morphology in 70.4% of Scanora and 62.4% of conventional examinations. In 12% of the patients, the roots were in very close contact with the canal determined by the surgeon. In approximately 50% of these cases, the close contact to the canal was found by radiography with no significant differences between the methods. CONCLUSION: The Scanora method was more accurate when validated against the surgeons' findings for the position and number of roots of ectopic mandibular third molars while both methods were equally accurate in demonstrating the relation between the roots and the inferior alveolar nerve.

Adolescent↗

Cementogenesis reviewed: a comparison between human premolars and rodent molars.

BACKGROUND: Cementum continues to be the least-known mineralized tissue. Although recent advances in the field of molecular biology have contributed to an understanding of the involvement of molecular factors in cementum formation during development and regeneration, cementogenesis on a cell biological basis is still poorly understood. Virtually nothing is known about cementoblast origin, differentiation, and the cell dynamics during normal development, repair, and regeneration. This review describes the recent findings of cementogenesis on roots of human premolars and opposes them to those of teeth from other mammals, particularly the rodent molar. METHODS: Using light and electron microscopy, light microscopic radioautography, and various measurements, a comprehensive insight into the development and repair of cementum during and after root formation and tooth eruption has been achieved for human premolars. RESULTS: Cementum is a highly responsive mineralized tissue. This biological activity is necessary for root integrity and for bringing and maintaining the tooth in its proper position. With regard to cementum formation and periodontal fiber attachment, considerable species-particularities exist that are mainly based on differences in growth rates and tooth sizes. Since root development and initial cementogenesis last on the average 5-7 years in human premolars, cementum formation in these teeth is characterized by along-lasting phase of prefunctional development, with occurs independent of principal periodontal fiber attachment to the root and which may take 5 years or more. The first molar of the rat, however, is in functional occlusion 3 1/2 weeks after the onset of root formation. Since initial cementum formation and periodontal fiber attachment to the root occur almost at the same time in this tooth, the distinction between cells associated with one or the other process is very difficult to achieve, and cementogenesis cannot be described independent of periodontal fiber attachment to the root. Therefore, the determination of cementoblast origin in the rodent molar may be intricate. CONCLUSIONS: Taking into account these species differences, the current description on the origin and differentiation of cementoblasts is inconsistent and the description of cementogenesis is still incomplete. This review calls into question the currently held concept of cementogenesis and offers a possible alternative.

Animals↗

Nerve fibres and cells immunoreactive to neurochemical markers in developing rat molars and supporting tissues.

The distribution of nerve fibres immunoreactive to calcitonin gene-related peptide (CGRP), substance P (SP) and neuropeptide Y (NPY) was compared to the general neurochemical markers for nerves and neuroendocrine cells protein gene product 9.5 (PGP 9.5) and neurone-specific enolase (NSE), by use of the avidin-biotin peroxidase complex method in developing dental structures in rats aged 13 to 27 days. A substantially greater part of the nerve fibres was immunoreactive to CGRP and SP than to NPY. In the bell stage, nerve fibres immunoreactive to PGP 9.5, CGRP and SP were found in the dental follicle but not in the dental papilla and stellate reticulum. In the advanced bell stage, after initiation of dentine and enamel formation, PGP 9.5, CGRP- and SP-immunoreactive fibres were found in the dental papilla, while the first NPY-immunoreactive fibres were observed in the papilla when root formation started. Concomitant with the beginning of root development, a subodontoblastic nerve plexus was gradually formed and PGP 9.5-, CGRP- and SP-immunoreactive fibres were found within the dentinal tubules. From the start of root formation, CGRP-, SP- and NPY-immunoreactive nerves were shown in the developing periodontal ligament, although a mature distribution pattern was not observed until root formation was nearly completed. Ameloblasts, odontoblasts and cell-like structures in the outer enamel epithelium and within the dental lamina were PGP 9.5-immunoreactive at the bell stage. As the tooth matured, the immunolabelling gradually decreased, but was still present in some odontoblasts after tooth eruption. NSE-immunoreactive, cell-like structures were found in the periphery of the dental follicle, and persisted close to alveolar bone in the periodontal ligament when the tooth reached occlusion. Hence, it may be concluded that sensory nerves containing SP and CGRP are present in the pulp in advance of sympathetic nerves immunoreactive to NPY.

Alveolar Process↗

Oro-dental manifestations in Hallopeau-Siemens-type recessive dystrophic epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa of Hallopeau-Siemens (RDEB-HS) is a rare genetic disorder characterized by trauma-induced blisters, milia, acral pseudosyndactyly, and scarring. RDEB-HS patients present with a distinct pattern of oral involvement consisting of microstomia, ankyloglossia, vestibule obliteration and dental caries. In this review, we describe the orodental manifestations of RDEB-HS and present our experience in a cohort of six new cases of RDEB-HS in children aged 6-10 years, documenting the presence of microstomia, ankyloglossia and vestibule obliteration in childhood. We also show that compared with unaffected control children, RDEB-HS subjects have a greater risk of developing high caries indices with early onset, both for permanent or deciduous teeth, and a worse oral hygiene index (scored as OHI). Tooth malpositions and the cross-bite relationship between maxilla and mandible could play a major role in promoting these events. We propose that dental management of RDEB-HS subjects should commence as soon as tooth eruption begins.

Child↗

[Induction of jaw bone formation by tooth autotransplantation].

A case-report of segmental underdevelopment of the alveolar process in the upper jaw of an eleven-year old girl is presented. At the site where the alveolar ridge was underdeveloped, two impacted malformed incisors were found. The malformed teeth had almost normal crowns, but the root-development had terminated 1-2 mm beyond the cementoenamel junction. The patient was treated by removal of the two malformed impacted teeth, followed by autotransplantation of the developing second premolar with the intention of inducing bone formation. The result was promising. After 3 years the alveolar process had developed to almost normal vertical hight. Some considerations are made regarding the possible origin of the bone induction factors in tooth buds. The fact that this patient demonstrated an underdevelopment of the alveolar process in spite of the formation of almost normal crowns, is taken as evidence that the bone stimulating principle in tooth buds are not to be found in the enamel organ proper, but must be related to Hertwig's epithelial sheath, root development and tooth eruption.

Alveolar Process↗