Comparative analyses among interfaces of some ceramic materials and bone in sheep

Aim of this work is the evaluation of “in situ” implants in an animal model to study the interfaces that some ceramic materials for dental bone defects develop with bone and to check which material is more osteoconductive.In a sheep’s jaw, eight holes were drilled and filled with six ceramic materials in granular shape. Two bilateral holes were left empty as reference. The ceramic materials were: porous tricalcium phosphate (TCP), porous hydroxylapatite (HA) and four bioactive glasses. The glasses differ for doping agents that affect the velocity of biodegradation in the living body.Monthly radiographs were taken and the X-ray pictures analyzed by means of a Video Display Computer in order to quantify the optical density changes occured in the holes. After 4 month implantation, the segments of the jaw containing the materials were fixed in paraformaldehyde, embedded in methylmethacrylate and sectioned.The results obtained under the microradiograph, the SEM and the X-ray microprobe showed a good bone repair only with TCP granules. A great degradation was seen in HA granules and particularly in glasses.The degradation modified the structure and the composition of the glass granules, but it was not followed by a consequent bone deposition.Des granules de Phosphate TriCalcique, de Hydroxyapatite et de trois céramiques bioactifs (A, AKRA 15 et 18) ont été implantés pendant 4 mois dans des cavités produites dans la mandibule d’un mouton, dans le but d’en évaluer les capacités ostéoréparatrices. Les études en microradiographie, au MEB et à la microsonde à rayons X des coupes de la mandibule, incluse dans le méthacrylate, mettent en évidence que seulement le PTC produit une réparation satisfaisante, tandis que les autres matériaux n’induisent pas une néoformation osseuse au niveau des lésions expérimentales

Implantations dentaires en alumine monocrystalline chez l’animal: étude du tissu périmplantaire

After the extraction of two molars in a dog’s jaw, a single crystal alumina screw was implanted.Monthly radiographs were taken and analyzed by means of a video display computer (VDC) to obtain densitometric informations about the interface.After one year implantation, the bone segment containing the prosthesis was fixed in 4% paraformadehyde, embedded in methacrylate and sectioned by a microtome saw.The results in light microscopy with ordinary and polarized light, in SEM and X-ray microanalysis, show the presence of a thick connective tissue layer interposed between the screw and the bone. The histological findings confirm the results obtained through the VDC analysis of the radiographic images.Un implant, sous forme de vis d’alumine monocrystalline, a été placé dans la mandibule d’un chien. Le pivot est resté in situ pendant 1 an sans être chargé.Les résultats des analyses des coupes au microscope photonique, au MEB et à la microsonde à rayons X mettent en évidence l’existence d’une couche épaisse du tissu conjonctif autour de l’implant et confirment les analyses, par analyseur digital (VDC), des radiographies endobuccales

Comparative study on bone regeneration of cystic lesions

Obiettivi. Determinare la rigenerazione ossea di difetti cistici delle ossa mascellari dopo riempimento con osso autologo o con copolimero PLA-PGA (Fisiograft ®) tramite valutazioni cliniche, radiologiche e istologiche. Materiali e Metodi. Otto pazienti maschi consenzienti, affetti da cisti odontogena in rapporto a elementi dentari a prognosi infausta in cui il trattamento endodontico clinico era fallito, sono stati sottoposti a intervento di enucleazione cistica e a innesto con osso autologo (gruppo di controllo GC) o con copolimero (gruppo di trattamento GT) con follow-up di 4 mesi. Risultati. I risultati clinici e radiologici (area, diametri, livelli di grigio) evidenziano un lieve miglior esito per il gruppo di controllo, senza differenze statistiche significative. L’analisi istologica delle biopsie di quattro mesi evidenziava uno steady-state osteogenico nel GC, con frammenti di osso risparmiato dagli osteoclasti e porzioni di osso neoformato. Osso neoformato a fibre intrecciate e attività fosfatasi alcalina positiva erano invece caratteristiche distintive del GT. L’ammontare di osso presente (TBV) non risultava differente nei due gruppi (m ~ 16,5%). Conclusioni. I risultati ottenibili con il copolimero, non molto diversi da quelli conseguiti con osso autologo, sono da considerarsi molto apprezzabili in considerazione della maneggevolezza del materiale e dell’assenza della necessità di un sito donatore secondario. Abstract Comparative study on bone regeneration of cystic lesions Objectives. To evaluate healing of cystic lesions in human jawbone filled with autologous bone or PLA-PGA copolymer (Fisiograft®), by means of clinical, radiological and histological methods. Material and Methods. After informed consent eight male patients underwent surgical treatment of dental cysts caused by teeth where endodontic treatment failed. Patients were randomly divided into 2 groups: the first (control group) received an autologous bone graft while the second (treatment group) was treated by copolymer with a follow-up of 4 months. Results. Autologous bone provided a lightly better clinical and radiological (area, diameters, gray level) outcome without statistically significant differences. Bone activities were enhanced in sites treated with copolymer, whereas a steady-state was observed with autologous bone. The amount of bone (TBV) was similar in both groups (m ~ 16,5%). Conclusions. Our results indicate that best outcomes are achieved using autologous bone graft, but good results can also follow the use of copolymer to promote healing of severe bone defects. Additionally, copolymer is easy to handle and does not require a secondary donor site.□Objectives. To evaluate healing of cystic lesions in human jawbone filled with autologous bone or PLA-PGA copolymer (Fisiograft ®), by means of clinical, radiological and histological methods. □Material and Methods. After informed consent eight male patients underwent surgical treatment of dental cysts caused by teeth where endodontic treatment failed. Patients were randomly divided into 2 groups: the first (control group) received an autologous bone graft while the second (treatment group) was treated by copolymer with a follow-up of 4 months. □Results. Autologous bone provided a lightly better clinical and radiological (area, diameters, gray level) outcome without statistically significant differences. Bone activities were enhanced in sites treated with copolymer, whereas a steady-state was observed with autologous bone. The amount of bone (TBV) was similar in both groups (m ∼ 16,5%). □Conclusions. Our results indicate that best outcomes are achieved using autologous bone graft, but good results can also follow the use of copolymer to promote healing of severe bone defects. Additionally, copolymer is easy to handle and does not require a secondary donor site

Effetto del calcitriolo sulla velocità dello spostamento dentario e sul tessuto osseo in corso di trattamento ortodontico in ratti giovani ed adulti.

Scopo della presente ricerca è valutare l’effetto del calcitriolo sulla velocità dello spostamento dentario e sul tessuto osseo in corso di trattamento ortodontico in ratti giovani ed adulti. Lo studio è stato eseguito su un totale di 80 ratti albini outbred Wistar maschi: 38 giovani (11-13 settimane di età) e 42 adulti (22-27 settimane di età). Un’inclinazione mesiale del primo molare superiore veniva ottenuta mediante l’applicazione di molle chiuse di nickel-titanio che liberavano una forza di 25 cN, applicate tra gli incisivi ed il primo molare. Gli animali, giovani ed adulti, comprendevano un gruppo di controllo ed un gruppo sperimentale suddiviso a sua volta in quattro gruppi in base alla durata del trattamento ortodontico: 3, 7, 14 e 21 giorni. Ad eccezione del gruppo di controllo tutti ricevevano, ogni tre giorni, un’iniezione intramucosa di 20 ml di calcitriolo (Calcijex, 10 –10 mol/L) a livello della superficie palatale mesiale del primo molare superiore di sinistra. Nel lato opposto veniva iniettato un uguale volume di PBS. Una parte degli animali trattati per 21 giorni subiva un trattamento aggiuntivo di tetraciclina allo scopo di ottenere la marcatura dell’osso in formazione. Nei soggetti adulti il movimento dentario sul lato sperimentale, che riceveva l’iniezione di calcitriolo, è risultato maggiore del 160 % (p<0,001) rispetto al lato trattato con solo PBS dopo 21 giorni di trattamento. In corrispondenza del lato sperimentale è stata osservata una più diffusa fluorescenza dell’osso alveolare compreso tra primo e secondo molare e della parete alveolare vestibolare dell’osso mascellare. L’analisi istochimica dell’attività osteoclastica, valutata su sezioni colorate per la fosfatasi acida tartrato resistente (TRAP), indica, nel lato sperimentale, una maggiore estensione delle aree interessate dall’erosione degli osteoclasti in animali adulti con tempo di trattamento di 3 giorni. L’analisi delle microradiografie delle sezioni dell’osso alveolare evidenzia che tessuto non calcificato risulta quantitativamente maggiore nel lato sperimentale rispetto al lato di controllo. La somministrazione di calcitriolo non presenta alcuna indicazione nei ratti giovani nei quali l’effetto del calcitriolo non sembra produrre variazioni della velocità dello spostamento dentario

A new histological method to study oral soft tissue penetrability to iodine and optimize oral use of iodine solutions

The aim of this work is to establish a histological method to fix iodine inside slides of treated oral mucosa more permanently in order to allow section counterstaining and facilitate improved clinical and experimental studies on iodine penetration. Transforming iodine into a stable histological formation inside tissues is particularly useful for histological analysis of clinical and experimental iodine treatments. In the field of oncology, this method can be applied to povidone-iodine-treated (human or animal) mucosa or skin, to organs treated with iodine tincture or Lugol’s solution, to oral lesion detection and to mucogingival junction identification

Induction and pharmacological treatment of oral osteopenia in rats.

3nonenoneZAFFE D.; COCCHI D.; C. PAGANELLIZaffe, D.; Cocchi, Daniela; Paganelli, Corrad

Histomorphometric study of bone reactions during orthodontic tooth movement in rats

Histomorphometric study of bone reactions during orthodontic tooth movement in rat

Rabbit bone behavior after orthodontic and pulsed low-frequency electromagnetic field treatments

The effect of low-frequency pulsed electromagnetic fields (PEMF) on bone was studied after an orthodontic treatment. A spring was positioned between the incisors and the first molar on both sides of the rabbit mandible for 14 days. A PEMF treatment was performed 6 h/day on the right side only. A greater distance between the first and the second molar was recorded in the PEMF treated side with respect to the left side. In addition, analysis of undecalcified sections shows a lower number and width of erosion cavities and a greater amount of newly formed (fluorescent) bone on the right side. In conclusion, PEMF treatment not only appears to increase bone formation, as previously reported in the literature, but, acting on osteoclast activity, also seems to improve bone quality during orthodontic treatment