Microsphere controlled drug delivery for local control of tooth movement.

Background: Because orthodontic tooth movement is dependent upon osteoclast-mediated resorption of alveolar bone adjacent to the pressure side of tooth roots, biologic mediators that regulate osteoclasts can be utilized to control tooth movement. Objectives: To develop a novel method to locally enhance orthodontic anchorage. Methods: We encapsulated osteoprotegerin (OPG) in polymer microspheres and tested the effectiveness of microsphere encapsulated versus non-encapsulated OPG for enhancing orthodontic anchorage in a rodent model of tooth movement. A single injection of 1 mg/kg non-encapsulated or microsphere encapsulated OPG was delivered into the palatal mucosa mesial to the first maxillary molar 1 day prior to tooth movement. A positive control group received injections of 5 mg/kg non-encapsulated OPG every 3 days during tooth movement. After 28 days of tooth movement, hemi-maxillae and femurs were dissected. Molar mesial and incisor distal tooth movement was measured using stone casts that were scanned and magnified. Local alveolar, distant femur bone, and tooth root volumes were analyzed by micro computed tomography. Serum OPG levels were measured by ELISA. Osteoclast numbers were quantified by histomorphometry. Results: The single injection of microsphere encapsulated OPG significantly enhanced orthodontic anchorage, while the single injection of non-encapsulated OPG did not. Injection of encapsulated OPG inhibited molar mesial movement but did not inhibit incisor tooth movement, and did not alter alveolar or femur bone volume fraction, density, or mineral content. Multiple injections of 5 mg/kg non-encapsulated OPG enhanced orthodontic anchorage, but also inhibited incisor retraction and altered alveolar and femur bone quality parameters. Increased OPG levels were found only in animals receiving multiple injections of non-encapsulated 5 mg/kg OPG. Osteoclast numbers were higher upon tooth movement in animals that did not receive OPG. Osteoclast numbers in OPG injected animals were variable within groups. Conclusions: Microsphere encapsulation of OPG allows for controlled drug release, and enhances site-specific orthodontic anchorage without systemic side effects. With additional refinements, this drug delivery system could be applicable to a broad array of potential biologic orthodontic therapeutics.

Direct Resin Composite Restoration of Maxillary Central Incisors with Fractured Tooth Fragment Reattachment: Case Report.

This article presents a clinical protocol to reconstruct two accidentally damaged maxillary central incisors using composite resin material and a fractured tooth component. A patient was referred to the clinic with fracture of the two maxillary central incisors. Clinical examination revealed that both teeth were fractured in the middle third of the crown and that the fractures involved enamel and dentin with no pulp exposure. The patient had also suffered a lower lip laceration. When the lip was evaluated, a fractured fragment of the maxillary right central incisor was found inside the wound. The missing part of the tooth was replaced via adhesive attachment. Due to the damage of the fractured part of the maxillary left central incisor, direct composite restoration of this tooth was performed. With the advent of adhesive dentistry, the process of fragment reattachment has become simplified and more reliable. This procedure provides improved function, is faster to perform, and provides long-lasting effects, indicating that reattachment of a coronal fragment is a realistic alternative to placement of conventional resin composite restorations.

Prenatally administered HMB modifies the enamel surface roughness in spiny mice offspring: An atomic force microscopy study.

OBJECTIVE: The aim of this research was to check the effect of the prenatally administered ß-hydroxy ß-methylbutyrate (HMB) on the development of enamel surface of the spiny mice offspring. DESIGN: The spiny mice dams were randomly assigned into three groups: control group (not supplemented with HMB) and two experimental groups in which powdered HMB was given at the daily dosage of 0.2g/kg of body weight (group I) and 0.02g/kg of body weight (group II) during the last period of gestation. Newborn pups were euthanized by CO2 inhalation. The morphology of incisor teeth was analysed using atomic force microscopy (AFM) in semi-contact mode in the height, magnitude and phase domains. Height images became a basis for determination of surface roughness parameters. RESULTS: Conducted study indicated that maternal HMB administration markedly influences enamel development. Enamel of offspring's teeth in both experimental groups was characterized by significantly smaller values of indices describing surface roughness and profile. HMB supplementation influenced the calculated parameters regardless of the diet type and offspring sex, however higher dose of HMB caused stronger changes in enamel surface's physical properties and could be observed in higher intensity in the male group. CONCLUSIONS: HMB administration caused reduction in the irregularities of enamel surface, thereby possibly reducing the probability of bacteria adhesion and caries development. These observations may serve to improve nutrition and supplementation of animals and could be a lead for further research.

[Behavior of the periodontium during leveling of the mandibular incisors: what precautions are needed?]. / Comportement du parodonte au cours du nivellement des incisives mandibulaires : précautions à prendre∗.

Since the position of the mandibular incisors is one of the keys to successful treatment, most orthodontic treatments focus on control but take no special precautions regarding the periodontal environment. Can we trust the lateral headfilm alone when evaluating such slender quantities of bone surrounding the mandibular incisors? What is the true bone situation prior to treatment and above all, following alignment, leveling and uprighting of the incisors? We performed a prospective 3-year study on 50 patients to assess the periodontal behavior of the mandibular incisors following a leveling phase by means of a clinical approach using periodontal and radiologic probing based on measurements of bone thickness obtained by cone beam. The bone loss observed was not inconsiderable given the thinness of the initial bone. In the face of this clinical situation, we need to adapt our treatment by performing a pre-orthodontic periodontal check-up and by supplementing the diagnosis with 3D examinations for at-risk patients and by checking the incisal axes during the leveling phase. The advent of cone beam has provided us with a valuable tool making it possible to individualize orthodontic treatment and view the posttreatment bone environment and root positions.

Sodium Thiosulfate for Recovery of Bond Strength to Dentin Treated with Sodium Hypochlorite.

INTRODUCTION: The aim of this study was to evaluate the efficacy of sodium thiosulfate (Na2S2O3) for restoring adhesion to pulp chamber dentin treated with sodium hypochlorite (NaOCl) and EDTA. METHODS: Sixty-three crowns of bovine incisors were cut to expose the dentin pulp chamber. The specimens were polished and randomly distributed into 9 groups (n = 7) according to the following protocols used: 0.9% sodium chloride for 30 minutes (negative control), 5.25% NaOCl for 30 minutes, 17% EDTA for 3 minutes, and 5.25% NaOCl for 1 minute (positive control). The other groups, after treatments with NaOCl and EDTA, were immersed in 0.5% or 5% Na2S2O3 for 1, 5, and 10 minutes or just immersed in an inert solution for 10 minutes (0.9% sodium chloride). After drying the specimens, Scotchbond Multi-Purpose (3M ESPE, St Paul, MN) was applied to the pulp chamber dentin followed by Filtek Z250 composite (3M ESPE). Six rectangular slabs were obtained from each specimen, and the dentin/resin interface was tested by using a universal testing machine. The resulting data were submitted to 1-way analysis of variance and the Duncan test (P = .05). RESULTS: There was a significant decrease in bond strength regarding NaOCl and EDTA (P < .05). When 5% Na2S2O3 was used for 10 minutes, the bond strength was found to be statistically equal to the negative control and higher than the positive control (P < .05). CONCLUSIONS: The use of Na2S2O3 can significantly increase the bond strength of composite resin to NaOCl/EDTA-treated dentin, allowing adhesive restorations to be immediately applied after endodontic treatment.

The use of a single-step regenerative approach for the treatment of a replanted mandibular central incisor with severe resorption.

AIM: To report the clinical and radiographic treatment outcome of an immature replanted mandibular incisor with severe inflammatory external root resorption following a single-step regenerative approach. SUMMARY: A 7-year-old female patient was referred 1 week following an extrusion injury to her mandibular central incisor (tooth 31). There was a history of a 6 months previous avulsion injury to the same tooth, which had been replanted after 20 min of extra-oral time. On clinical examination, all teeth were asymptomatic and there was an arch wire splint placed on the mandibular incisors. Radiographic examination revealed severe inflammatory external root resorption of tooth 31. A diagnosis of necrotic pulp and asymptomatic apical periodontitis was made. Under local anaesthesia and rubber dam isolation, an access cavity was prepared. The canal was irrigated using 6% NaOCl solution delivered through the EndoVac negative pressure irrigation system (Endo Vac, Axis/SybronEndo, Coppell, TX, USA). A 17% EDTA solution was used for 5 min followed by a final rinse of sterile water. The periapical tissues were probed using a K-file, and bleeding was induced. A blood clot was allowed to form filling the entire canal. A thick plug of MTA was placed in direct contact with the blood clot. The tooth was restored with composite resin. All procedures were performed in a single visit. The splint was removed 2 weeks later. Recall examination after 24 months revealed healthy soft tissues with normal periodontal probing and mobility. The 24 months radiographic evaluation revealed healing of the severe inflammatory external root resorption and continuous root development/dentine wall thickening of the apical third. No signs of ankylosis or significant discoloration was present.

Morphological features of the maxillary incisors roots and relationship with neighbouring anatomical structures: possible implications in endodontic surgery.

The purpose of this study was to investigate the relationship between the root apex of the upper incisors and neighbouring anatomical structures as well as the morphology of the root-end foramen after apicoectomy. Fifty-seven patients requiring endodontic surgical treatment for a maxillary anterior root were enrolled. A preoperative diagnostic computed tomography (CT) scan was analysed to determine: the distance between the anterior wall of the nasopalatine duct and the central (CI-ND) incisor root 4mm from the apex; and the distance between the floor of the nasal cavity and the tip of either the central (CI-NF) or the lateral (LI-NF) incisor root. After apicoectomy, root-end foramen endoscopic pictures were taken in order to characterize their morphology. Fifty-nine central and 26 lateral incisors were evaluated. The average CI-ND was 4.71 ± 1.26 (SD) mm. The average CI-NF was 10.62 ± 2.25 mm. The average LI-NF was 13.05 ± 2.43 mm. The foramen shape after apicoectomy was ovoid to circular in about 90% of cases in both central and lateral incisors. A sound knowledge of the anatomical relationships at the surgical site is essential for the clinician to perform a safe endodontic surgical procedure.

Doppler ultrasound to detect pulpal blood flow changes during local anaesthesia.

AIM: To examine whether Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. METHODOLOGY: Changes in pulpal blood flow in maxillary central incisor teeth of 18 patients (mean age 26.7 years, 13 men, five women) after infiltration anaesthesia were examined. Before infiltration anaesthesia, the pulpal blood flow was measured using Doppler ultrasound. A local anaesthetic solution containing 2% lidocaine with 1:80,000 epinephrine was injected into the submucosa above the experimental tooth. The Doppler ultrasound test was carried out at 5, 10, 20, 30, 45 and 60 min after infiltration. The parameters were Vas (maximum linear velocity, cm s(-1) ), Vam (average linear velocity, cm s(-1) ) and Vakd (minimum linear velocity, cm s(-1) ), which are indicators of the level of blood flow. The mixed procedure at the 95% confidence interval was used to examine the changes in pulpal blood flow after the injection. RESULTS: The linear velocity profiles (Vas, Vam, and Vakd) decreased sharply 5 min after anaesthesia and then reduced continuously for 30 min. The maximum degree of blood flow reduction in Vas, Vam and Vakd was 58%, 83% and 82%, respectively. After 30 min, the linear velocities increased gradually. The Vam returned to the pre-anaesthesia state at 60 minutes but the Vas and Vakd did not recover completely. CONCLUSIONS: Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. In the future, Doppler ultrasound can be used as a tool for measuring pulpal blood flow.

Preservation of an injured vital tooth using ultrasonic device and mineral trioxide aggregate.

The purpose of this case report is to present a root fracture repair procedure for non devitalized injured tooth. One injured, non-endodontically treated maxillary anterior tooth in which an incomplete vertical root fracture involving only the buccal side was suspected, underwent an exploratory flap to visualize the pattern of bone loss and assess the type of root fracture. The pre-operative diagnosis was confirmed. A groove following fracture line was prepared using retro-tips driven by an ultrasonic device and sealed with Mineral Trioxide Aggregate (MTA), following filling of the bone defect with Calcium Sulphate. At 24 months follow up the case showed clinical and radiographic success. The present surgical approach showed preservation of function and vitality of tooth with a shallow incomplete vertical root fracture.

Study of the effectiveness of propolis extract as a storage medium for avulsed teeth.

The purpose of the present study was to evaluate the efficacy of propolis extract in maintaining the viability of human periodontal ligament (PDL) cells, and to radiographically analyze tooth replantation and the adjacent periodontium in dogs after storage in this extract. Human PDL cells were incubated with the experimental media propolis, milk, saliva, Hank's balanced salt solution (HBSS), and Dulbecco's modified Eagles medium (DMEM, positive controls), and distilled water (negative control). Cell viability was determined 0, 1, 3, 6, 12, and 24 h later by colorimetric MTT assay. Thirty incisors from dogs were divided into two storage time blocks (1 and 3 h) and were maintained in the experimental media. HBSS served as a positive control, and dry teeth (on gauze) as a negative control. The replanted teeth were radiographed once per month for 6 months. The radiographic images were standardized by the shortening/lengthening factor, and were both qualitatively and quantitatively analyzed. The in vitro results showed that the efficacy of propolis in maintaining functional viability of PDL cells was similar to that of milk. Propolis and milk were significantly better than controls from the 6-h time period. The in vivo results showed that teeth maintained in propolis medium exhibited replacement resorption with significant reduction in tooth length, similar to teeth maintained in saliva and dried teeth. This resorption was less intense with the 3-h storage time than the 1-h storage time. Conditions close to normal were found in teeth maintained in milk, similar to the HBSS control. Therefore, although propolis was effective in maintaining the viability of human PDL cells, resorption of the tooth replantation in dogs occurred under these experimental conditions.

Re-attachment of anterior tooth fragment using a self-etching adhesive: a case report.

AIM: The purpose of this case report is to describe the re-attachment of an anterior tooth fragment using a self-etching adhesive. BACKGROUND: Fracture of anterior teeth by trauma is a common problem in children and teenagers due to their active lifestyle. Restoration of these teeth often presents a challenge because of the large pulp in young teeth and open apical foramen depending on the age of the child. New dental adhesive materials offer an alternative solution for the treatment of some anterior tooth fractures. REPORT: A 17-year-old female patient presented for treatment of a fractured maxillary left central incisor. The clinical examination revealed the exposure of dentin, but there was no exposure of the pulp. The patient saved the tooth fragment making it available for re-attachment to the remaining tooth structure. Under local anesthesia and rubber dam isolation the tooth fragment was re-attached using a self-etching adhesive and a microhybrid composite. SUMMARY: The re-attached tooth fragment was assessed clinically, radiographically, and using photographs at one, six, 12, 24, and 36 month intervals. The tooth remained vital, and there was no change in the color of the tooth at the three-year recall.

Remineralization effects of gum arabic on caries-like enamel lesions.

OBJECTIVE: Gum arabic is a natural polysaccharide exudate from Acacia senegal and other related African species of Acacia. Gum arabic is considered to have an ability to enhance remineralization, because of its high concentration of Ca(2+). However, the caries preventive capacity of gum arabic has been scarcely investigated. We evaluated the cariostatic activities of gum arabic using histopathological methods to determine its effects on remineralization. DESIGN: Following incubation in demineralization solution, human third molars were exposed to 10 mg/ml of gum arabic, sodium fluoride at 1000 ppm (NaF), or double distilled water (DW, negative control), then subjected to demineralization-remineralization cycles. Before and after demineralization-remineralization cycles, contact microradiographs of each sample were taken and mineral distribution quantities were calculated. RESULTS: The remineralization ratio of the molars exposed to gum arabic was similar to that of those exposed to NaF, while the ratios of both were significantly greater than that of those exposed to DW. CONCLUSIONS: Gum arabic enhanced the remineralization of caries-like enamel lesions in vitro, suggesting its inhibitory effects towards dental caries.

Removal of the smear layer from flattened canals using different chemical substances.

This study used scanning electron microscopy to evaluate the flattened root canals of human mandibular incisors cleaned with nickel-titanium instruments and different chemical substances. Teeth were selected and divided randomly into five groups (n = 10) according to the chemical substances used in the biomechanical preparation: 5.25% sodium hypochlorite (Group 1), 5.25% sodium hypochlorite plus a final irrigation with 17% EDTAC (Group 2), EDTA gel combined with 5.25% sodium hypochlorite (Group 3), 2% chlorhexidine gel (Group 4), and 5.25% sodium hypochlorite combined with Glyde File Prep gel (Group 5). Data analysis showed a statistically significant difference (p < 0.001) among groups. Groups 1 and 5 were similar statistically (p > 0.001) and displayed a higher amount of smear layer on canal walls. Samples from Groups 2, 3, and 4 revealed root canal walls without smear layer and exposed dentin tubules. Among the associations tested in this study, 5.25% sodium hypochlorite solution combined with 17% EDTAC, 5.25% sodium hypochlorite combined with EDTA gel, and 2% chlorhexidine gel all were effective substances for removing the smear layer from flattened root canals.

Effect of various Ca2+/PO4(3-) concentrations of linseed-based saliva substitutes on enamel in vitro.

Remineralization might be hampered by various polymers used in saliva substitutes. Thus, the present study evaluated the effects of various calcium and phosphate concentrations of linseed-based solutions on the mineral loss of pre-demineralized bovine enamel in vitro. A commercially available saliva substitute (Salinum) based on linseed was tested as well. Enamel specimens were prepared from bovine incisors and embedded in epoxy resin. One-third of each sample was covered with nail varnish (control of sound enamel). After demineralization (37 degrees Celsius; pH 5.0; 14 days) another third of the samples was nail-varnished again. Subsequently, the specimens (n = 10) were exposed to 12 linseed-based solutions (Ca(2+) addition 0-2 mM; PO4(3-) addition 0-3.2 mM) at pH 5.5 and 6.5 as well as to Salinum) for 14 days (37 degrees Celsius). The differences in mineral loss between the values prior to and after the storage in the various solutions were evaluated from microradiographs of thin sections (100 mum). The general linear model revealed a significant dependency for the mineral loss on 'calcium' (P = 0.003), but not on 'pH' (P = 0.397) and 'phosphate' (P = 0.094). Salinum) induced a significant greater mineral loss compared with equivalently saturated solutions (P < 0.05; anova, Bonferroni). The solution with the highest calcium and phosphate concentration showed the greatest mineral gain (P = 0.033; paired t-test). The addition of calcium and phosphate seems to have a positive effect on the remineralizing qualities of linseed-based saliva substitutes.

Periodontal healing after intentional auto-alloplastic reimplantation of injured immature upper front teeth.

BACKGROUND/AIMS: Conventional endodontic treatment results in high complication quota when performed in immature teeth. Intentional reimplantation with extraoral insertion of an endodontic implant (auto-alloplastic reimplantation) is an alternative. METHOD: In a retrospective study, the healing of 40 teeth reimplanted intentionally according to this method in patients aged 7 to 15 years was evaluated. Clinical tests (palpation, percussion sound, periotest values) and radiographical examinations were used to determine the type of periodontal healing (inflammatory resorption/periodontitis apicalis; replacement resorption/ankylosis; normal healing). RESULTS: Mean lifetime of the replanted teeth was 59.2+/-42.5 months, estimated survival time on the basis of the Kaplan-Meier analysis was 99.5 months. 17 teeth (42.5%) were classified as failures, mostly due to inflammatory resorption or periodontitis apicalis. Further investigations demonstrated that success rate and retention period of intentionally replanted teeth depend on the preoperative condition of the pulp. Teeth with preoperative infection suffered frequently from inflammatory resorption or periodontitis apicalis after being replanted (14 of 28 teeth). Estimated survival time according to Kaplan-Meier was 75.5 months. In contrast, inflammations or progressive resorptions were not observed in teeth without preoperative infection of the pulp. All these 12 teeth showed normal periodontal healing and regular tooth mobility. In the absence of any pathology in clinical or radiological findings after an average functional period of 72.3 months, the prognosis can be presumed excellent. Estimated survival time of 148.3 months according to Kaplan-Meier differs significantly from survival time of teeth infected preoperatively. CONCLUSIONS: From the results of this investigation, it may be concluded that an infection of the pulp - due to delay of treatment or attempts at endodontic therapy - should be avoided before intentional replantation of immature front teeth with pulp necrosis. Periodontal healing of the autologous root is not impaired by the insertion of posts made of Al2O3-ceramics or titanium. The inserted posts do not ankylose. Orthodontic movement of auto-alloplastically replanted teeth is possible.

The treatment of nonvital immature teeth with calcium hydroxide-sterile water paste: two case reports.

Death of the dental pulp before completion of root development results in a tooth with an open apex. During endodontic treatment, the open apex makes obturation difficult, because there is no apical stop against which the filling can be packed and condensed. For many years, open apices have been treated by root canal fillings or by periapical surgery with or without a reverse seal. Currently, the conservative approach is preferred over surgical management, to avoid the physical and psychological trauma of surgery to a young patient. Two patients were treated by calcium hydroxide-sterile water paste to promote the apexification of the nonvital teeth with an incompletely formed apex. Normal endodontic preparation of the canal had been carried out in the immature tooth. Radiologic examination after 6 to 9 months showed that the apex of the maxillary incisors was completed by newly formed tissue.

The diagnostic value of coronal dark-gray discoloration in primary teeth following traumatic injuries.

The diagnostic value of dark-gray discoloration of the crown of primary incisors following traumatic injury as a predictor of pulp vitality is controversial. This retrospective study attempted to examine the condition of the pulp of primary incisors with dark-gray discoloration following traumatic injuries. Forty-eight gray caries-free, traumatized primary incisors were examined clinically and radiographically prior to treatment. All teeth included in the study were free of any clinical and/or radiographic signs of pulp necrosis. Crown discoloration was the only clinical or radiographic sign of pulp involvement. Pulpectomy was performed in five teeth within the first month after trauma, in 16 teeth during the second month, 11 teeth between 2 and 6 months, seven teeth between 6 and 12 months, and three teeth after more than a year. In six teeth the time of injury was unknown. Endodontic treatment was initiated without local anesthetic under rubber dam, access to the pulp chamber with high speed, and debridement with a barbed broach. Assessment of the pulp condition was made upon opening the pulp chamber, as follows: Vital-pulp bled when exposed; partial necrosis-bleeding disclosed at the apical area during debridement; total necrosis-no bleeding was observed. Pulp necrosis was found in 37 teeth (77.1%), 10 teeth (20.8%) presented partial necrosis, and only one tooth (2.1%) had a vital pulp. Dark-gray discoloration of primary incisors could be interpreted as an early sign of pulp degeneration that would deteriorate into necrosis. Moreover, discolored primary incisors can be necrotic even without presenting tenderness to percussion, increased mobility, and periapical osteitis.

Front tooth replacement with Tübingen (Frialit) implants: a radiographical evaluation.

A total of 214 radiographs of 76 Tübingen implants placed in the anterior region of the maxillae of 56 patients were evaluated by two observers. The first radiographs were taken after implant placement (n = 76). The second set of radiographs were taken during months 13-23 (n = 53), the third during the months 24-35 (n = 28), the fourth during months 36-47 (n = 15), the fifth during months 48-59 (n = 18) and the sixth during months 60-72 (n = 20). Only four radiographs were available after longer periods, namely the eight and the ten year of function. The two observers together classified the marginal bone height (mesial and distal) as 0 (no resorption) or 1-5 in steps of 2.5 mm resorption. A score of 1 represents marginal bone resorption less than 2.5 mm, 2 from 2.5 mm to 5 mm, 3 from 5 to 7.5 mm, 4 from 7.5 to 10 mm and 5 more than 10 mm loss of marginal bone height. Thirty-six implants scored marginal bone height of 0 or 1. Twenty-two implants scored not higher than 2. Eight implants scored bone loss up to 3, four up to 4 and one up to 5. Five implants were lost.

[The congenital absence of the permanent upper lateral incisors with the persistence of the deciduous canines in a subject of the Iron Age from the Sulmona (AQ) necropolis]. / Assenza congenita degli incisivi laterali superiori permanenti con persistenza dei canini decidui in un soggetto dell'età del Ferro della necropoli di Sulmona (AQ).

The paper reports a case of bilateral agenesia of the permanent upper lateral incisors associated with the persistence of the deciduous eye teeth placed between the first premolars and the permanent canine teeth which, in turn, had emerged in place of the agenetic lateral incisors (situs dentis inversus) in a adult male from the Iron Age whose skeletal remains were exhumed from tomb no. 58 of the Sulmona necropolis (AQ). The authors place the case in the context of agenesia as found both in today's population and in ancient times.