Amount Of Alveolar Bone Research Articles

Dental Auto-transplantation to Premolar Mandibullary Sites: Case report

ABSTRACT This study aims to present the success rate, advantages, and factors influencing the success, along with potential complications associated with autotransplantation to the mandibular premolar region. Autotransplantation involves the extraction of a suitable impacted, semi-erupted, or erupted tooth from an individual, followed by surgical transplantation into areas of tooth loss within the same individual. This procedure is particularly significant in addressing tooth loss, especially among young patients, with its success dependent on the careful selection of appropriate cases. Indications for autotransplantation include premature tooth loss resulting from various causes such as irreparable teeth, periodontal diseases, root fractures, dental agenesis, early tooth loss due to trauma, and impacted or ectopic teeth. The primary criteria for evaluating the success of autotransplantation involve normal periapical healing and sustained root development, without inflammatory pulpal changes or root resorption. The tooth designated for autotransplantation underwent initial treatment with a root canal, followed by complete filling with MTA to prevent root resorption. Subsequently, it was positioned and secured in the designated transplant area. The patient was called for periodic check-ups after the treatment was completed. Despite its limited practical applications, autotransplantation serves as a valid alternative to implant and prosthetic treatments due to its cost-effectiveness, relative simplicity, and ability to provide satisfactory aesthetics and functional results. Additionally, it preserves the quality and quantity of alveolar bone. In this study a 5-year follow-up of the patient revealed no criteria indicating failure in the transplanted tooth. Keywords: Autotransplantation, ectopic teeth, root resorption

Scientific rationale for Clinical Practice Guidelines (part 1): what are the factors that determine the choice of retention?

Retention is the set of means, processes or devices that contribute to maintaining the teeth in the position and the arches in the shape given by the orthodontic treatment. The main objective is to propose Clinical Practice Guidelines (CPG) on orthodontic retention by answering 4main questions. This article provides the answer to the first question: What are the factors that determine whether or not to use a retainer? A literature review was carried out after a bibliographic search using keywords in bibliographic databases and in international organizations websites. 652articles were selected after the bibliographic search, and only 53met the inclusion criteria. These were used to develop the CPG full-text and guidelines. 12CPGs were issued from this review, divided into 15items, 8of which were gradeC and 7were expert agreements. 40CPGs about orthodontic retention were proposed from this literature review, 12of which are presented in this first part. The stability of orthodontic treatment depends on the initial orthodontic anomalies, residual growth, orthodontic treatment modalities, and the final occlusion. Orthodontists must consider the effectiveness of the appliances, the patients' compliance and oral hygiene. The amount of alveolar bone, the neuromuscular and functional balance are relapse factors.

Pertimbangan pemasangan implan gigi pada pasien lanjut usia

Background: The elderly population is a group of people who are vulnerable have tooth loss so it is common to use of dental implant for replace it. Unfortunately, decreased function and changes in the condition of the tissues of the oral cavity and alveolar bones due to the aging process are often make installation of implant more complicated. Futhermore, in the elderly often found systemic diseases such as hypertension, diabetes mellitus, osteoporosis or cardiovascular diseases that affect the installation of implants. But if the quality and quantity of alveolar bone and soft tissue are adequate accompanied by a healthy elderly condition, it is possible that implant placement will be succesfull.
 Case Report: A 69-years-old male patient attended a clinic to replace his missing right lower teeth with permanent denture. After undergoing several examinations, it was decided to perform dental implant on tooth 46, diameter 3.8 mm and length 10.5 mm with a cemented-screw type PFM crown. The implant and PFM crown were successfully placed in tooth 46 and patients were comfortable with the implant without any complaints of pain.
 Conclusion: chronological age by itself is suggested as one of the risk factors for success, but it would not be a contraindication as long as the condition of the alveolar bone is adequate and systemic disease is well controlled.

Maxillary Sinus Dimensions in Skeletal Class I Chinese Population with Different Vertical Skeletal Patterns: A Cone-Beam Computed Tomography Study.

Due to the close relationship between the maxillary posterior teeth roots and the maxillary sinus floor, the maxillary sinus can significantly impact various dental treatments, including endodontic procedures and surgical apicectomy, periodontal flap surgery, surgical tooth extraction, dental implantation, and orthognathic surgeries. Specifically, in orthodontics, the location of the maxillary sinus floor may affect tooth movement and insertion of temporary anchorage devices (TADs). This study aims to evaluate the dimensions and location of the maxillary sinus in the Chinese orthodontic patient population with skeletal class I. Using cone-beam computed tomography (CBCT), the volumetric size, height, width, and depth of the sinus and the amount of alveolar bone below the sinus floor and buccal/palatal to the sinus wall were compared between patients of different genders and different vertical skeletal patterns. Unlike the previously reported skeletal class II population, the skeletal class I patients with different vertical patterns do not have significantly different size sinuses. On the other hand, males have larger maxillary sinuses in all parameters than females in the testing population. In addition, no significant correlation was noticed between the SN-MP angle and sinus dimensions or between the ANB angle and sinus dimensions. Nevertheless, the distance from the sinus floor to the alveolar bone crest is not correlated with skeletally sagittal or vertical parameters in females but negatively correlated with the skeletal sagittal parameter in males. In summary, different from the skeletal class II population, there is no significant difference in maxillary sinus size and location among different vertical skeletal patterns in the skeletal class I population. Compared to the skeletal class II population, a higher percentage of the skeletal class I population has an alveolar bone with less than 5 mm thickness, representing a narrowed safe zone of TADs placements.

Maxillary and dental development in the offspring of protein-restricted female rats.

Nutritional restriction during developmental periods impairs organ physiology. Female rats were subjected to protein restriction during pregnancy and lactation to analyze dental and maxillary development. Four exposure groups were considered: normal-protein diet during pregnancy and lactation (NP, 17% casein), low-protein diet during lactation (LP-L, 6% casein), low-protein diet during pregnancy and lactation (LP), and low-protein diet during pregnancy (LP-G). Maxillae from 15-day-old male pups were collected. All protein-restricted groups presented increased dentin thickness and reduced alveolar bone area. When protein restriction was applied during both gestation and lactation (LP), harmful effects were observed in the form of loss of protective OPG (osteoprotegerin) in tooth epithelium-mesenchyme, due to higher RANKL expression, delay in odontoblast maturation, less dental pulp vascularity, reduction in amount of alveolar bone, and less matrix mineralization. In the LP-L group, effects of protein restriction seemed less harmful, and despite less alveolar bone, the enhancement in BMP-7, VEGF, and RANKL seems a compensatory signal to maintain maxillary osteogenesis. In LP-G animals, Dspp expression was higher, suggesting a delay in odontoblast maturation or expression recuperation. In conclusion, maternal protein restriction affects dental and maxillary development. A low-protein diet only in gestation allows for normal development. A low-protein diet during gestation-lactation results in impaired odontogenesis that may increase susceptibility of dental anomalies.

Status of the alveolar bone after autotransplantation of developing premolars to the anterior maxilla assessed by CBCT measurements.

Background/AimsAutotransplantation of developing premolars is an established treatment to replace missing teeth in the anterior maxilla in growing patients with a reported success rate of over 90%. The normal shape of the alveolus is observed after transplantation, but data on the presence and amount of alveolar bone after healing has not been previously reported. The aim of this study was to look for potential differences in alveolar bone dimensions between sites where autotransplanted premolars replaced missing incisors and control sites of contralateral incisors.Material/MethodsThere were 11 patients aged between 10 and 12 years five months (mean age: 10 years and 7 months) who underwent autotransplantation of a premolar to replace a central incisor. Cone Beam Computed Tomography (CBCT) performed at least 1 year after transplantation served to evaluate bone at sites of autotransplanted premolars and controls (contralateral maxillary central incisor). The thickness of the labial bone, plus the height and width of the alveolar process were measured on scans and compared at transplant and control sites.ResultsMean thicknesses of the labial bone at the transplant and control sites were 0.78 mm and 0.82 mm respectively. Mean alveolar bone height was 15.15 mm at the transplant sites and 15.12 mm at the control sites. The mean marginal thickness of the alveolus was 7.75 mm at the transplant sites and 7.98 mm at the control sites. Mean thicknesses of the alveolus for half of its vertical dimension at the transplant and control sites were 7.54 mm and 8.03 mm, respectively.ConclusionThe mean values of bone thickness, width and height of the alveolar process at sites of transplanted premolars were comparable to the mean values for the control incisors. Successful autotransplantation of developing premolars to replace missing central incisors allowed preservation of alveolar bone in the anterior maxilla.

Cone-Beam Computed Tomography Analysis of the Prevalence, Length, and Passage of the Anterior Loop of the Mandibular Canal.

When placing implants in the anterior mandible, it is important to avoid damaging the mandibular nerve and its terminal extensions. The objective of this study was to determine the prevalence, length, and passage of the anterior loop of the mandibular canal, as well as the quantity of alveolar bone that is coronal to the canal, to help with implant placement in the anterior mandible. Cone-beam computerized tomography (CBCT) scans of 124 patients with 248 hemi-sections were evaluated. Anterior loop prevalence was determined using reconstructed panoramic and cross-sectional views; length was measured as the distance between the most mesial aspect of the mental foramen to the most mesial aspect of the anterior loop on cross-sectional views. The bucco-lingual position of the anterior loop inside the mandible and the apico-coronal dimensions of the alveolar bone above it were measured on cross-sectional views to determine the passage of the anterior loop and the bone available coronally, respectively. The effects of sex, age, side, and dentate status on the prevalence and length of the anterior loop were analyzed statistically. Prevalence of the anterior loop at the patient and hemi-section levels was 25% and 24%, respectively, and its median length was 1.63 mm (range, 0.52-3.92 mm). The anterior loop was apical to the mental foramen and mostly located within the buccal or middle one-third of the alveolar ridge, with an average height of coronal alveolar bone of 17.12 mm. Sex, age, side, and dentate status did not affect anterior loop prevalence and length. In conclusion, because of great variation, a case-by-case CBCT evaluation of the anterior loop is necessary before placing implants in the anterior mandible.

Alveolar bone height and thickness assessed by CBCT

Abstract Objectives To seek information regarding the relationship between the quantity of alveolar bone and the angle and sagittal position of the incisors. This was to be further determined in relation to the basal bones and facial pattern with the aim of establishing a predictive model based on the study of a lateral cephalogram. Methods The distance from the cemento-enamel junction to the labial alveolar crest and the bone thickness half-way along the root of the most prominent upper and lower incisor were measured in a sample of 100 cone beam computed tomography (CBCT) scans of patients aged between 15 and 34 years. Lateral cephalograms of the patients were extracted from the scans and used to measure the buccolingual angle and antero-posterior position of the incisors in addition to the facial pattern of each patient. Results A correlation was found between bone thickness around the upper incisor and the variables of the incisal angle and its sagittal position. The inclination of the lower incisor (IMPA) was related to cortical bone thickness. The cemento-enamel junction to alveolar crest measurement (bone height) was related to the antero-posterior position of the lower incisor in men. The facial pattern was unrelated to any of the variables. Conclusions The angle and sagittal position of the upper and lower incisors were associated with alveolar bone thickness in men. Only the antero-posterior position of the lower incisor was related to its alveolar bone height. In women, only the angle of the lower incisor was associated with bone thickness.

Novel bioceramic-reinforced hydrogel for alveolar bone regeneration.

The osseointegration of dental implants and their consequent long-term success is guaranteed by the presence, in the extraction site, of healthy and sufficient alveolar bone. Bone deficiencies may be the result of extraction traumas, periodontal disease and infection. In these cases, placement of titanium implants is contraindicated until a vertical bone augmentation is obtained. This goal is achieved using bone graft materials, which should simulate extracellular matrix (ECM), in order to promote osteoblast proliferation and fill the void, maintaining the space without collapsing until the new bone is formed. In this work, we design, develop and characterize a novel, moldable chitosan-pectin hydrogel reinforced by biphasic calcium phosphate particles with size in the range of 100-300μm. The polysaccharide nature of the hydrogel mimics the ECM of natural bone, and the ceramic particles promote high osteoblast proliferation, assessed by Scanning Electron Microscopy analysis. Swelling properties allow significant adsorption of water solution (up to 200% of solution content) so that the bone defect space can be filled by the material in an in vivo scenario. The incorporation of ceramic particles makes the material stable at different pH and increases the compressive elastic modulus, toughness and ultimate tensile strength. Furthermore, cell studies with SAOS-2 human osteoblastic cell line show high cell proliferation and adhesion already after 72h, and the presence of ceramic particles increases the expression of alkaline phosphatase activity after 1week. These results suggest a great potential of the developed moldable biomaterials for the regeneration of the alveolar bone. The positive fate of a surgical procedure involving the insertion of a titanium screw still depends on the quality and quantity of alveolar bone which is present in the extraction site. Available materials are basically hard scaffold materials with un-predictable behavior in different condition and difficult shaping properties. In this work we developed a novel pectin-chitosan hydrogel reinforced with ceramic particles. Polysaccharides simulate the extracellular matrix of natural bone and the extensive in vitro cells culture study allows to assess that the incorporation of the ceramic particles promote a pro-osteogenic response. Shape control, easy adaption of the extraction site, predictable behavior in different environment condition, swelling properties and an anti-inflammatory response are the significant characteristics of the developed biomaterial.

Radiographic evaluation of anatomical variables in maxilla and mandible in relation to dental implant placement.

Oral rehabilitation using implants is rapidly replacing tooth supported prostheses. The success of implants is largely dependent on the quality and quantity of alveolar bone. In this study, we assessed the location of limiting anatomical structures and the amount of alveolar bone available for implant placement. Six hundred digital panoramic radiographs (300 males and 300 females) of dentate patients aged between 15-60 years were selected from the archives. The radiographs were subdivided into 3 groups with age interval of 15 years. Then the location of mental foramen, anterior loop, mandibular canal and maxillary sinus was determined. The amount of bone available was measured in both maxilla and mandible in the premolar and molar regions. The mental foramen was most commonly located at the apex of the second premolar in both the genders. The anterior loop was more readily visible in the younger age group. The amount of bone available in the premolar and molar region of the mandible is nearly the same, while more bone is available in the premolar region of the maxilla. The location and morphology of anatomical structures of the jaws vary not only in different populations but also within the same population. The amount of bone available also showed variations in the same population and in the same individual on the right and left sides. The limiting anatomical structures govern the amount of bone available for possible implant placement.

임플란트 증례에서 발생하는 심미적 문제점들에 관한 고찰

전치부 임플란트의 심미성에 영향을 미치는 중요한 요소는 다음과 같다. 1) 임플란트 식립체의 올바른 위치, 2) 치조골의 충분한 양, 3) 연조직의 최적의 양. 임플란트 위치는 심미적인 치료결과를 얻는 데에 가장 중요한 요소일 것이다. 임플란트의 3차원적 위치는 치조제의 위치와 방향에 의해 결정된다. 임상가들은 수복물을 제작할 때 흔히 자연치를 모방하려 한다. 그러나 심미적인 진단 및 치료를 하는 과정에서 잊지 말아야 할 것은 얼굴형태, 입술, 치은, 치조제, 그리고 잔존치아들과의 상관관계를 고려하는 것이다. 전치부는 구치부에 비해 생물학적으로 불리하며, 조금이라도 임플란트 위치가 틀어지면 심미적으로 좋지 않은 결과를 야기할 수 있다. 임플란트 3치원적 위치의 생물학적, 보철적 의미를 이해한다면, 전치부에 더욱 심미적인 결과를 얻을 수 있을 것이다. The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture, 2) Enough amount of alveolar bone, 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant' s 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

Comprehensive approach with implant

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture 2) Enough amount of alveolar bone 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant's 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

Three-dimensional observations of the incisive canal and the surrounding bone using cone-beam computed tomography

The shape of the anterior region of the maxilla is critical when planning implant treatment. The purpose of the present study was to assess the typical morphology of the incisive canal and surrounding bone. In total, 70 maxillae of Japanese dry skulls were used after being divided into dentate and edentulous groups. Cone-beam computed tomography (CBCT) images of the maxilla were acquired by using standardized methods. Using the anterior nasal spine as a reference point, the change in position was measured and analyzed statistically. Also, three-dimensional (3-D) images of the incisive canal were classified into five subsets: cylinder, groove, penetration, bifurcation at the superior portion, and bifurcation at the inferior portion. The quantity of alveolar bone in the incisor region was greatly reduced from the alveolar ridge and labial surface. Moreover, the vertical position of the incisive foramen was significantly (P < 0.05) superior in the edentulous groups. Regarding the classification of maxillae by the 3-D shape of the incisive canal, many canals were cylindrical. Horizontal bone reduction from the labial side and vertical bone reduction from the alveolar crest were conspicuous; thus, the angle of the anterior alveolar bone changed after the loss of teeth. The incisive canal diameter in the edentulous group was larger than in the dentate group. The nondestructive assessment of the incisive canals and surrounding bone with CBCT showed two typical shapes for the presence or absence of the incisors. These findings indicate the importance of image diagnosis before esthetic restoration.

A ortodontia na atuação odontogeriátrica

OBJETIVO: este artigo tem como objetivo abordar as características do tratamento ortodôntico associado a uma atuação odontogeriátrica, pois devido a um aumento da expectativa de vida, um maior número de pacientes idosos tem procurado tratamento odontológico para uma reabilitação estética e/ou funcional. METODOLOGIA: através de uma avaliação de dados presentes na literatura são abordados fatores como enfermidades sistêmicas, uso de medicamentos, condição da saúde bucal, quantidade de osso alveolar, motivação do paciente e estabilidade oclusal após a terapia ortodôntica. Para exemplificar o tratamento ortodôntico no paciente idoso são apresentados dois casos clínicos. CONCLUSÕES: o tratamento ortodôntico representa uma intervenção viável na atuação odontogeriátrica, desde que realizado com forças suaves, considerando as limitações de cada caso e respeitando as características inerentes a esta atuação.

Morphologic Analysis of the Incisive Canal With CBCT

WITH CBCT. R. Asaumi, T. Kawai, I. Sato, S. Yoshida, and T. Yosue, Nippon Dental University, Tokyo, Japan. Objectives. The shape of the anterior region of the maxilla is critical when the implant treatment is planned. The purpose of the present study was to assess the typical morphology of the incisive canal and surrounding bone with respect to the presence or absence of the upper incisors. Materials and methods. The maxillas of 68 Japanese dry skulls were used and divided into a dentate group and an edentulous group. Cone-beam computerized tomography (CBCT) images of the anterior region of the maxilla were acquired. With the anterior nasal spine (ANS) as a reference point, the change of position was measured and analyzed statistically. Also the microscopic specimens around the incisive canals obtained from cadavers were observed histologically, and the internal structures of incisive canals were inspected. Results. The quantity of alveolar bone in the incisor region was greatly reduced from the alveolar ridge and labial surface; therefore the alveolar ridge was located in the posterior and palatal position in the edentulous group. Moreover, it was confirmed that there was also influence on the palatal bone posterior to the incisive canal, because a vertical position of the incisive foramen had been significantly (P .05) superior in the edentulous groups. The incisive canal had many nerves and blood vessels which were less than 1 mm in diameter. Discussion. The horizontal bone reduction from the labial side and the vertical bone reduction from the alveolar crest were conspicuous; therefore the angle of the anterior alveolar bone changed after the loss of teeth. The incisive canal diameter increased after loss of the incisors. The nondestructive assessment of the incisive canals and surrounding bone with CBCT derived 2 typical shapes for the presence or absence of the incisors. These findings indicated the importance of image diagnosis before esthetic restoration.

Three-year treatment outcomes with three brands of implants placed in the posterior maxilla and mandible of partially edentulous patients

Survival rates of implants in posterior regions vary among clinical studies. Problems occur more often in the posterior segment of the maxilla due to proximity of the maxillary sinus and reduced quality or quantity of alveolar bone. This clinical study evaluated the treatment outcomes of 3 brands of implants in the posterior maxillae and mandibles of 63 patients. Treatment outcomes of all implants were assessed according to implant type, location, patient gender, periodontal status, and prosthesis type. A total of 203 implants-105 ITI (ITI), 53 Camlog (CAM), and 45 Frialit (FRI)-were placed in 63 patients (38 women, 25 men). One hundred twelve implants were located in the posterior mandible and 91 in the posterior maxilla. All implants were longer than 10 mm and had a diameter larger than 3.5 mm. Implants in the ITI group were placed in a 1-stage surgery. The CAM and FRI groups were treated with a 2-stage surgical protocol. Implants were not loaded until osseointegration was complete, which was determined clinically and radiographically. At that point, implants were restored with 50 single crowns and 81 fixed partial dentures (FPDs). While 11 FPDs connected implants to natural teeth, 70 FPDs were supported by implants only. Standardized radiographs were made, and clinical parameters were recorded at prosthesis insertion (baseline) and at each recall evaluation (6, 12, 24, and 36 months). Plaque index (PI), sulcus bleeding index (SBI), peri-implant probing depth (PD), and radiographic marginal bone loss (MBL) levels were recorded at baseline, along with any biological and mechanical complications. Repeated-measures ANOVA, Kruskal-Wallis test, Wilcoxon signed rank test, and paired samples tests were used for statistical analysis (alpha=.05). One implant was lost during the osseointegration period in 1 woman due to infection. The cumulative implant treatment outcome was 99.3%. At the 3-year recall, plaque accumulation was significantly higher than baseline scores (P=.01, Wilcoxon signed rank test). Eight percent of the patients presented>2 mm PD at 2-year recall. The influence of observation time was found to be significant for the mean MBL values between groups (P=.001). When MBL values were compared between groups, no significant differences were found. For 1 patient in the FRI group, abutment loosening was observed and both the crown and the abutment were replaced. Patient satisfaction in all groups was high. The 3 brands of implants evaluated in this study exhibited similar positive treatment outcomes after 3 years.

Mandibular phenotype of p20C/EBPβ transgenic mice: Reduced alveolar bone mass and site-specific dentin dysplasia

CCAAT enhancer binding proteins (C/EBP) comprise a family of basic-leucine zipper transcription factors that regulate cellular differentiation and function. To determine the role of C/EBP transcription factors in osteoblasts and odontoblasts, we generated a transgenic (TG) mouse model with Co1a1 (pOBCol3.6) promoter-targeted expression of a FLAG-tagged dominant negative C/EBP isoform, p20C/EBPβ (previously LIP). Two of the four transgenic lines presented with abnormalities in the developing incisors, including breakage, overgrowth, and malocclusion. Histological examination revealed that the amount of alveolar bone was reduced in TG compared to wild-type (WT) mice. By microcomputed tomography (microCT), the bone volume fraction of the mandible was reduced at the level of the first and third molars, demonstrating a severe mandibular osteopenia. The lingual dentin morphology of TG incisors differed dramatically from WT. Labial dentin (enamel side) showed normal thickness and tubular dentin structure, whereas the lingual dentin was thinner (25–30% of WT at the alveolar crest) with an amorphous globular structure characteristic of dentin dysplasia. FLAG immunostaining was seen in both lingual and labial odontoblasts, indicating that the site-specific defect was not due to a lack of labial transgene expression. Northern blot analysis demonstrated reduced osteocalcin expression in TG mandibles, while bone sialoprotein was increased, consistent with prior results in calvariae and long bones. Dental sialophosphoprotein, a marker of the odontoblast lineage whose absence causes dentin dysplasia, was modestly reduced in TG mice by Northern blot and in situ hybridization analysis. By fluorescence microscopy, pOBCol2.3-GFP, a marker of the odontoblast lineage, was expressed in both labial and lingual odontoblasts, although GFP-marked lingual odontoblasts were more flattened than WT cells. Moreover, GFP-positive processes in the lingual dentin tubules were truncated and less organized than those in WT dentin. MicroCT analysis showed reduced tissue density in the lingual dentin. These data suggest that C/EBP transcription factors may be involved in the regulation of odontoblast polarization and dentin matrix production.

Bone structure effect on root resorption.

To explore if alveolar bone shape and density might promote external apical root resorption. Panoramic radiographs of 700 patients who had orthodontic treatment at Temple University were reviewed and 22 patients with radiographic evidence of root resorption on the lower incisors were selected for the study. Exclusion criteria included a history of systemic diseases, craniofacial abnormalities, tooth injury, endodontically treated teeth, and impacted teeth. Pre-treatment (T1) and post-treatment (T2) cephalometric radiographs were converted into digital format and enhanced to reduce contrast variability and improve edge definition. Tooth length, root length, root area, alveolar area around the root including cortical area, area of medullary bone, and area of the symphysis were measured using an interactive software algorithm. A region of interest within the symphysis was also defined and trabecular space area and fractal dimension calculated as an estimate of bone density. Root area and tooth length were correlated negatively with changes in root area, tooth area, and root length. Larger teeth demonstrated a greater amount of root resorption. Dentoalveolar complex dimensions remained relatively unchanged during tooth movement. The amount of alveolar bone around the root, thickness of cortical bone, density of the trabecular network, and fractal dimension showed no significant correlation with the extent of the external apical root resorption. The results of this study suggest that the density and morphology of the dentoalveolar complex are not significant factors in the etiology of external apical root resorption.

Effects of Tumor Necrosis Factor-α Inhibitors Pentoxifylline and Thalidomide on Alveolar Bone Loss in Short-Term Experimental Periodontal Disease in Rats.

Pentoxifylline (PTX) and thalidomide (TLD) have been shown to inhibit cytokine synthesis, mainly tumor necrosis factor (TNF)-α, in different inflammatory conditions. We studied the effects of these cytokine inhibitors in an experimental model of periodontitis. Wistar rats were subjected to a ligature placement around the second upper right molars. Alveolar bone loss was evaluated by the sum of the distances between the cusp tip and the alveolar bone along the axis of each molar root, subtracting from the contralateral side. Histopathological analysis was based on cell influx, amount of alveolar bone, and cementum integrity. Animals were weighed daily, and total and differential peripheral white blood cell counts were performed at 6 hours and 1, 7, and 11 days after induction of periodontitis. Groups were treated with saline (positive control), PTX, or TLD 1 hour before and daily up to 11 days after induction of periodontitis. Alveolar bone loss was inhibited 42%, 54%, and 69% by PTX at 5, 15, and 45 mg/kg, and 25%, 25%, 42%, and 54% by TLD at 5, 15, 45, and 90 mg/kg, respectively, as compared to the control (P <0.05; analysis of variance). Histological analysis showed that PTX and TLD reduced cell influx and alveolar bone and cementum destruction. PTX and TLD also reversed peripheral lymphomonocytosis but not weight loss, as compared to controls. These data showed that both PTX and TLD reduced alveolar bone loss in periodontitis. The data showed a protective effect of PTX and TLD on experimental periodontitis, suggesting a role for TNF-α in the pathophysiology of periodontitis. J Periodontol 2004;75:162-168.

The progress of the periodontal syndrome in the rice cat. II. The effects of a diphosphonate on the periodontium.

The effects of a diphosphonate, dichloromethylene diphosphonate (C12MDP) were studied using the rice rat as a model of periodontal bone loss. C12MDP was given in daily subcutaneous injections at dosages of 0 (control), 0.1, 1.0, or 10.0 mg/kg/day; these treatments were continued for periods of 6, 12, or 18 weeks. The amount of alveolar bone was increased over age matched controls at the 1.0 and 10.0 mg/kg/day doses at 6 weeks; at 12 and 18 weeks, all doses including 0.1 mg/kg/day showed increases in bone over controls. Due to increased connective tissue fibrosis, the CI2MDP treated animals had fewer vascular spaces. Also, the amount of destroyed tissue in the interdental test site was increased in animals given 10.0 mg/kg/day of C12MDP. The number of fibroblasts per mm of bone surface decreased slightly at 6 weeks, but was otherwise not different from controls in treated animals at 12 and 18 weeks. Numbers of osteoblasts decreased greatly at all doses at both 12 and 18 weeks time. There were no significant differences between treated and control animals in the number of osteoclast nuclei per mm bone surface. Also, the numbers of inflammatory cells residing at the bone surface increased at all time periods in the 10.0 mg/kg/day dose group. Finally, the proliferative activity of PDL fibroblasts decreased dramatically at all time periods in the 10.0 mg/kg/day dose group. The response of the proximal tibia to C12MDP was compared to the alveolar bone response in these animals by measuring amounts of bone in respective areas. While the dose response curves are similar, the tibiae showed greater increases in bone mass.