Gutta-percha (G) and sealer do not resist coronal leakage. In this study, the effect of orifice plugs using dentin-bonding/composite resin(C) or IRM on coronal leakage was evaluated in vivo. Sixty-one premolar roots in three beagle dogs were instrumented and filled with G and AH 26(S), or G alone. The coronal 2 mm was replaced with C or IRM, or left untreated. The access cavities were kept open for 8 months, the dogs were killed and the periapical regions of the roots were histologically examined. Periapical inflammation was observed in 89% of the group without plugs, but in those with plugs, the occurrence was decreased to 39% (C + G + S), 38% (IRM + G + S) and 58% (C + G), respectively. Furthermore, severe inflammation was observed in 50% of the former group but only 0 to 17% of the latter. The substantial reduction in apical periodontitis by the use of coronal plug underscores the clinical importance of providing an additional barrier to coronal leakage in comparison to that provided by gutta-percha and sealer alone.

A dog model was used to assess and compare in vivo the efficacy of gutta-percha and AH26 sealer versus Resilon with Epiphany primer and sealer [Resilon "Monoblock" System (RMS)] filled roots in preventing apical periodontitis subsequent to coronal inoculation with oral microorganisms. There were 56 vital roots in the premolars of seven adult beagle dogs aseptically instrumented, filled, and temporized. The roots were randomly divided into four experimental groups (Coronal Leakage Model) and one negative control group and filled as follows: group 1-lateral condensation of gutta-percha and AH26 sealer (n=12); group 2-vertical condensation of gutta-percha and AH26 sealer (n=12); group 3-lateral condensation of RMS (n=12); group 4-vertical condensation of RMS (n=10); negative control (n=10)-gutta-percha and AH26 sealer or RMS root fillings using lateral or vertical condensation techniques as in groups 1 to 4. Positive control-57 additional premolar roots were instrumented, infected and not filled (beginning of the Entombment Model experiment). The premolars in groups 1 to 4 were accessed again, inoculated with dental plaque scaled from the dog's teeth, and temporized. This fresh innoculum of microorganisms was repeated on two more occasions at monthly intervals. The teeth in the negative control group were not accessed again and remained undisturbed. On the 14-wk postcoronal inoculation, dogs were euthanized, and jaw blocks prepared for histologic evaluation under a light microcope. Mild inflammation was observed in 82% (18 of 22) of roots filled with gutta-percha and AH26 sealer that was stastistically more than roots filled with RMS (19% or 4 of 21) and roots in the negative control (22% or 2 of 9) (McNemar paired analysis, p < 0.05). The Resilon "Monoblock" System was associated with less apical periodontitis, which may be because of its superior resistance to coronal microleakage.

Increased levels of systemic inflammatory markers have been observed in patients with chronic dental diseases, such as marginal periodontitis. A canine model was used to determine if a systemic inflammatory response was evident during chronic apical periodontitis (CAP). Dental pulps in 10 dogs were exposed and infected with dental plaque to induce CAP. Blood samples were drawn preoperatively and postinfection when CAP was seen radiographically. In three of the 10 dogs, an intravenous challenge of Porphyromonas gingivalis A7436 was given subsequent to the development of CAP. An ELISA assay was used to measure the levels of C-reactive protein (CRP) and serum amyloid A (SAA) as markers of systemic inflammation. During CAP the levels of CRP and SAA were not statistically different from the preoperative values as determined by the Friedman test (p < 0.05). One dog, which had an unplanned trauma-induced laceration of the paw 2 days before blood sampling, showed a 40-fold increase in CRP. The 3 dogs challenged by intravenous P. gingivalis A7436 showed elevated levels of CRP, consistent with an acute phase response. These data demonstrate that the canine model provides a useful means for studying the systemic effects of apical periodontitis, and show that CAP is not associated with elevated CRP or SAA.

Coronal microbial leakage is an important cause of apical periodontitis and thus should be prevented if possible. The purpose of this study was to compare microbial leakage of new and standard obturation techniques over a 30-day period. A split chamber microbial leakage model was used in which Streptococcus mutans placed in the upper chamber could reach the lower chamber only through the obturated canal. Leakage was assessed every day for 30 days. One hundred forty single-rooted human teeth were used in this study, equally split between lateral, vertical, and Obtura II condensation; SimpliFill with Obtura II condensation; FibreFill; and a combination of FibreFill and SimpliFill. Cochran-Mantel-Haenszel row mean score statistics showed a high statistical significance when all groups were compared (p < 0.0001). Microbial leakage occurred more quickly in lateral and vertical condensation techniques compared with SimpliFill and FibreFill techniques. A combination of an apical plug of gutta-percha with SimpliFill and a FibreFill coronal seal was the best obturation technique used (SimpliFill-FibreFill group).

Aim oxide aggregate (NITA) or amalgam root-end Fillings in extracted teeth under low-vacuum (LV) versus high- vacuum (HV) scanning electron microscope (SEM)viewing conditions.Methodology Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with NITA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1,50 turn (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoatcd (LVDU)). The sections were then air-dried. gold-coated and gap size was recorded once again at. the fixed points under HV (10)(-6) Torr; HV dry coated (HVDC)). Specimen cracking. and the size and extent of the crack were noted.Results Gap sizes at fixed points were smallest under LVW and largest under HVDCSEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis. with gap size Lis the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001).Conclusions This study showed that NITA produced a Superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, it correction factor of 3.5 and 2.2, respectively may be used to enable relative comparisons of gap size to LVW conditions.

The purpose of this study was to compare bacterial leakage using Streptococcus mutans and Enterococcus faecalis through gutta-percha and a thermoplastic synthetic polymer-based root filling (Resilon) using two filling techniques during a 30-day period. Teeth were decoronated, roots prepared to a length of 16 mm, and instrumented to ISO sizes 40 to 50. A total of 156 roots were randomly divided into 8 groups of 15 roots (groups 1-8) and 3 control groups (12 roots each). Roots were filled using lateral and vertical condensation techniques with gutta-percha and AH 26 sealer (groups 1 and 2) or with gutta-percha and Epiphany sealer (groups 3 and 4). Groups 5 and 6 were filled with Resilon and Epiphany sealer using the lateral or vertical condensation techniques. A split chamber microbial leakage model was used in which S. mutans placed in the upper chamber could reach the lower chamber only through the filled canal. Groups 7 and 8 were identical to groups 5 and 6 respectively; however, E. faecalis was used to test the leakage. Positive controls were filled with Resilon (12 roots) and gutta-percha (12 roots) without sealer and tested with bacteria, whereas negative controls (12 roots) were sealed with wax to test the seal between chambers. All but one positive control leaked within 24 h, whereas none of the negative controls leaked. Resilon showed minimal leakage (group 8: one leakage; groups 5-7: each with two leakages), which was significantly less than gutta-percha, in which approximately 80% of specimens with either technique or sealer leaked. Kruskal-Wallis test showed statistical significance when all groups were compared (p < 0.05). Mann-Whitney U test compared the respective groups and found Resilon groups superior to gutta-percha groups (p < 0.05).

A case is presented where the mesially impacted mandibular second molar teeth were surgically uprighted in an 11-year-old female patient. Bone regeneration is shown in the areas occupied by the impacted second molars with maturation of bone and cortication of the crest of the alveolar bone. The probing depths are also normal with no residual bony defects. This healing was achieved with no bone grafting procedure, emphasizing two important factors: to prevent/minimize any trauma to the tissues at the site of elevation and uprighting of the tooth (i.e. maintaining viable periodontal ligament cells and minimal cementum damage); and to obtain primary closure whilst allowing the tissue in the mesial defect to reorganize against the scaffold of bone. However, the procedure on the one side was complicated with necrosis and infection of the pulp space with external inflammatory root resorption. Endodontic therapy of this tooth proved to be successful with periradicular healing radiographically and re-establishment of the lamina dura. At the 3-year follow-up, the endodontically treated tooth showed no clinical and radiographic signs of pathology. The left second mandibular molar had no pulpal or periodontal postsurgical complications, which may be attributed to apparently more open apices allowing for pulp revascularization after manipulation at the time of surgery. This report illustrates unassisted wound healing that occurs in the area of uprighting with complete reconstitution of periodontal anatomy without additional regenerative procedures to augment bone.