How tough is that root canal?

It is not uncommon to be faced with difficult treatment planning decisions when a patient presents with an endodontic problem during a routine day in the practice of general dentistry. Signs and symptoms of pulpal or periapical disease dictate the need for decision-making, and frequently the result of that decision is magnified by the patient experiencing severe pain. Our purpose is to present a link between case selection based on risk factors and the self-assessment of the dentist regarding his or her ability or motivation to treat a given case.     

Why do I need a root canal?

Bacteria invading the pulp cause pulpal necrosis and the need for endodontic treatment. If bacteria are present after treatment, the root canal may fail. For the root canal to be successful in necrotic cases or retreating failing cases, the bacteria in the root canal walls must be removed and the canal sterilized with calcium hydroxide.     

How does canal taper affect root stresses?

AIM: To examine the effect of specific tapers on root stresses and thus vertical root fracture. METHODOLOGY: The effect of taper on root stresses was calculated during simulated warm vertical compaction of gutta-percha in a straight rooted premolar for three tapers (0.04, 0.06 and 0.12 mm mm(-1)) using finite element analysis. Stresses in the dentine were observed whilst the root was filled with three subsequent gutta-percha increments. Each increment was compacted at 10 or 15 N and the gutta-percha cooled down to 37 degrees C. After filling, composite was polymerized in the access space. A functional occlusal load of 50 N was then applied on the buccal cusp incline. The stress distribution in the root during the occlusal loading was compared with the stresses during filling. RESULTS: During filling, the highest stresses were found: (a) at the canal surface; (b) using the smallest taper; (c) in the apical third; and (d) during the first gutta-percha increment. The root stress distribution changed when the functional post-filling load was applied. It generated the highest stresses at the external root surface, with a tensile stress concentration at the lingual surface of the cervical third. Since the stresses during simulated masticatory loading concentrated on the external surface, an increased taper size caused only slightly higher root stress levels. CONCLUSIONS: With increasing taper, root stresses decreased during root filling but tended to increase for masticatory loading. Root fracture originating at the apical third is likely initiated during filling, whilst fracture originating in the cervical portion is likely caused by occlusal loads.     

Comparison between two thermoplastic root canal obturation techniques regarding extrusion of root canal filling—a retrospective in vivo study

Objectives

The aim of this study was to compare two different thermoplastic techniques—a core-carrier technique (Thermafil) and warm vertical compaction—in terms of overextension of root canal filling in vivo.

Materials and methods

Flaring of 88 teeth was conducted using Pro Files .04 as finishing files, and the teeth were obturated using Thermafil. Flaring of 74 teeth was performed using Pro Files .06 as finishing files, and the teeth were obturated using warm vertical compaction.

Results

Seventy (80 %) of the teeth obturated using Thermafil and 31 (42 %) teeth obturated using warm vertical compaction show extruded root canal filling. In contrast to Thermafil, there is a higher rate of extruded root canal filling of teeth with more than one root canal using warm vertical compaction.

Conclusion

Thermafil demonstrated a higher rate of extruded root canal filling compared to warm vertical compaction. Warm vertical compaction is a more predictable method of filling compared to Thermafil.

Clinical relevance

Root canal filling extrusion will cause irritation of the surrounding tissue and impair repair processes. In the present in vivo study, there was a higher rate of root canal filling extrusion using Thermafil compared to warm vertical compaction.     

CarisolvTM: an alternative to NaOCl in immature root canals?

AIM: To test the null hypothesis that Carisolv is no more effective than 1% sodium hypochlorite in cleaning uninstrumented, immature root canals. METHODOLOGY: A total of 240 uniform, immature ovine incisors were decoronated at the CEJ level and randomly divided into four groups of 60. After gross pulp extirpation, canals were flooded with normal saline (negative control), 1% NaOCl, Carisolv or 5% NaOCl (positive control) and incubated for 10 min (group 1), 20 min (group 2), 30 min (group 3) or 30 min, refreshing irrigant at 10 and 20 min (group 4). SEM photomicrographs of canal wall debris in the apical, middle and coronal thirds were scored against a 5-point scale. Internal consistency was assessed by kappa statistics. Debris scores for different irrigant regimes at different canal levels were analysed by non-parametric tests (P < 0.05). RESULTS: Canals were consistently cleaner in the coronal and middle than apical thirds. NaOCl (5%) was consistently most effective. Carisolv and NaOCl (1%) were no more effective than normal saline in group 1 (P > 0.05), but significantly more effective than normal saline in groups 2 (middle and apical 1/3), 3 and 4 (P < 0.05). Carisolv and NaOCl (1%) had comparable activity in groups 1, 2 (middle and apical thirds) and 3, but NaOCl (1%) was significantly more effective than Carisolv in group 4 (coronal and middle thirds). CONCLUSIONS: 1.The ovine incisor model presents opportunities to investigate irrigation regimes under controlled ex-vivo conditions. 2.NaOCl (5%) remains the most effective irrigant for rapid debris removal in immature root canals. 3.Carisolv cleans pulp debris from the walls of immature root canals as effectively as NaOCl (1%) during static, unrefreshed wall contact for between 20 and 30 min. 4. Refreshment of NaOCl (1%) enhances its cleaning ability above that of Carisolv.     

How useful is root canal culturing in predicting treatment outcome?

Microbial control--fundamental to healing of apical periodontitis--is central to endodontic practice. The effectiveness of antibacterial measures is generally monitored (in clinical research studies) by microbiological root canal sampling (MRS), which is often used as a predictor for healing. This article addresses the question of the extent to which positive or negative cultures at time of obturation are able to predict treatment outcome. To date only one small clinical study has attempted to relate the treatment outcome to intraradicular bacterial status (p = 0.025, Fisher's exact test): the strength of the association was not great, with a wide confidence interval (odds ratio = 6.8; 95% CI: 1.5 to 32). The extent to which current canal sampling techniques accurately reflect the bacterial status of the canal space must also be taken into account. False positive and negative cultures may adversely affect the performance of MRS. These conditions emphasize how potentially error-prone MRS can be. As currently practiced, intracanal sampling techniques suffer from deficiencies that limit their predictive value. This article in no way questions the role of intracanal bacteria in causing apical periodontitis, nor the central role of bacterial control in endodontic treatment. Rather, it emphasizes the need for more detailed clinical studies of bacterial status and healing, as well as refinement of techniques for microbial sampling of canals.     

Characterization of maxillary central incisor: novel crown–root relationships

Objectives

The periodontal biotype includes crown features of the maxillary central incisor (MCI), whereas root measures have been less studied. The aim of our study was to morphologically characterize MCI and search relationships between crown and root measures.

Material and methods

One hundred-fifty MCIs were used. On each tooth, several crown and root reference points were marked and the following measures were done: On crown: mesio-distal (MD?=?major, md?=?minor), axial (crown length, cervical convexity) and buccolingual diameters (Cbl); On root: mesio-distal (Rmd) and buccolingual diameters (Rbl); and tooth length. A ratio between md and MD was made in order to assess dental forms. Root diameter prediction was assessed by means of multiple and single linear regression analyses, with variable selection by backward method. Reliability of measurements was estimated by the Pearson correlation coefficient.

Results

Dental form groups were: Stout type 56.67 %, Intermediate type 22.67 %, and Strangled type 20.67 %. A significative association was found between Rbl and Cbl (p?=?0,000), Rmd with md (p?=?0.000), and Rmd with MD (p?=?0.000). The results allow predicting root diameters through crown measures.

Conclusions

There is a direct relationship between crown and root features, which allows the prediction of root diameters with a high accuracy (95 %), regardless of tooth form.

Clinical relevance

The morphometric data assess tooth diameters more accurately and could improve treatment planning, offering a more comprehensive approach to the periodontal biotype concept.     

Severe external apical root resorption��local cause or genetic predisposition?

Background

Current data suggest that a large extent of the variation in orthodontic root resorption may be explained by differences in individual genetic predisposition. This would imply, however, a similar root resorption reaction in all teeth.

Objective

To determine the incidence and extent of severe external apical root resorptions (SEARR) in maxillary incisors during multibracket (MB) appliance treatment.

Patients and methods

Of the whole sample of patients having completed MB treatment at the University of Giessen between 1991 and 2010 (P_Total=3198), all subjects exhibiting severe root resorptions on at least one maxillary incisor were selected. SEARR were defined according to Malmgren et al. [39] (grade-IV RR=resorption >1/3 root length). Evaluation was performed using orthopantomograms from before and after MB treatment. The crown and root length of the affected teeth were measured. The extent of SEARR was assessed taking pretreatment crown length into consideration.

Results

SEARR was detected in 16?patients. Thus, the incidence of SEARR on maxillary incisors during MB treatment totalled 0.5%. The median of SEARR of the affected incisors was 38.6% of the initial root length (minimum=33.4%, maximum=61.0%). Most subjects exhibited only single affected teeth. Only two subjects (0.06% absolute/12.5% relative) presented four maxillary incisors with SEARR.

Conclusions

The incidence of SEARR on maxillary incisors during MB treatment (0.5%) was very low compared to the literature. With only 12.5% of SEARR patients presenting four affected teeth, local rather than systemic/genetic factors seem to have predisposed the present subjects to SEARR.     

Improved single visit management of old infected iatrogenic root perforations using Biodentine®

Aim

The aim of this retrospective observational case series study was to evaluate the middle term outcomes on endodontic management of old infected iatrogenic root perforations using Biodentine. The treatments were always concluded in a single visit, without previous medication with calcium hydroxide. Our goal was to facilitate this kind of treatments and to make them more reproducible and manageable even for a general practitioner or a student.

A new self-designed “tongue root holder” device to aid fiberoptic intubation

Objective

In this study, we aimed to assess the feasibility of fiberoptic intubation (FOI), using a new, self-designed, “tongue root holder” device, in combination with the jaw thrust maneuver.

Methods

Three hundred patients undergoing elective surgery requiring orotracheal intubation were enrolled. Patients presented at least one or more risk factors for difficult airway. The patients were randomly allocated at a 1:1 ratio to one of two groups: group L, FOI with tongue root holder, or group C, standard FOI. Orotracheal FOI was performed after commencement of anesthesia. The jaw thrust maneuver was applied in both groups to facilitate advancement of the fiberoptic bronchoscope. The primary endpoint was the feasibility of FOI. The secondary endpoints were number of attempts, time to intubation, and airway clearance at the soft palate and epiglottis levels.

Results

The FOI was achieved in all 150 patients in group L, significantly higher than that in group C (100% vs 95.3%; P = 0.015). Less attempts of intubation were made in group L (P = 0.039). Mean time to successful intubation on the first attempt was shorter in group L (P < 0.001). The mean times to view the vocal cord and carina were also shorter in group L (P = 0.011 and P < 0.001, respectively). Airway clearance was better in group L at both the soft palate and the glottis levels (P = 0.010 and P = 0.038, respectively).

Conclusions

This study shows that FOI is feasible with the newly introduced, self-designed, “tongue root holder” device, when combined with the jaw thrust maneuver in patients with risk factors for difficult airway. The device also provides better airway clearance, less intubation attempts, and shorter time to intubation at first attempt.

Clinical relevance

Fiberoptic bronchoscope has been the gold standard for routine management of difficult airway. A technique to open the airway is introduced to reduce the incidence rate of upper airway obstruction.

     

Posterior auricular artery helix root free flap—part II: clinical application

The surgical repair of full-thickness defects involving the alae nasi is complex. Pedicle flaps such as frontal and nasolabial flaps can be used, but require several interventions with different techniques. In contrast, free flaps from the foot of the ear helix allow the three layers of the nasal wings to be reconstructed in a single operation. Nevertheless, in the classical approach, the vascular pedicle is short. Although some authors have proposed raising the flap in a retrograde manner, this still yields a relatively short pedicle with narrow vessels. In the companion paper, we demonstrated that a posterior auricular artery helix root free flap (PAAHF) can be harvested from the posterior auricular vessels, thus increasing the useful pedicle length. The case of a patient with basal cell carcinoma of the left ala is presented here. A right helix root free flap was anastomosed with the facial vessels at the left mandibular notch. This new flap overcomes the main limitation of the classical helix root flap, namely the length of the pedicle. It has all of the morphological qualities of the classical flap, but with simpler vascular assembly, since autologous venous grafts and complex anastomoses are not required.