Instrumentation Time Efficiency and Histologically the Debriding Efficacy.
Instrumentation Time Efficiency and Histologically the Debriding Efficacy.
The goal of pulp therapy in the primary dentition is to retain the primary tooth as a fully
 functional part of the dentition, allowing at the same time for mastication, phonation,
 swallowing, and the preservation of the space required for the eruption of the permanent
 tooth. The premature loss of primary teeth may cause changes in the chronology and sequence
 of eruption of permanent teeth. Maintenance of primary teeth until physiological exfoliation
 prevents deleterious habits in children.

 The primary objectives of cleaning and shaping the root canal system are removing soft and
 hard tissue containing bacteria, providing a path for irrigants to the apical third,
 supplying space for medicaments and subsequent obturation, retaining the integrity of
 radicular structure. The choice between pulpotomy and pulpectomy is generally based on the
 severity of the symptoms clinically and/or radiographically. When indicated, the primary
 tooth pulpotomy is a relatively simple procedure with generally good clinical results.
Patient selection was based on the following criteria:

 -  the aims and requirements of the study were freely accepted by the parents;

 -  primary molars with at least 11.0 ± 1.0 mm of working length

 -  Treatment was limited to patients in good health;

 -  All teeth had vital and non-vital pulps without a sinus tract;

 -  Excess of bleeding during a pulpotomy; 6) Presence of enough coronal tooth and root
 structure;

 -  No prior pulpectomy treatment on the involved tooth,

 -  absence of perforation in the internal and/or external furcation area and

 -  No analgesics or antibiotics were used before the clinical procedures began. Exclusion
 criteria were patients without inclusion requirements or failure to obtain parent´s
 authorization, and were excluded if they were older than 7 years old, had a positive
 history of antibiotic use within the past month, diabetic, hemophilic or if the tooth
 had root resorption or been previously accessed and initiated a pulpectomy.

 Once eligibility was conﬁrmed, the parents were informed of the study design, the clinical
 procedure involved, and the associated risks. Patients aged 4-7 years of age were enrolled in
 this study, forty-five teeth (19 maxillaries and 26 mandibular teeth), which had a total of
 102 canals and completely formed apices and of minimum 10 mm root length were selected. All
 selected teeth had mature apexes with no radiographic sign of root resorption.

 Of the 45 treated primary molars, 31 teeth were diagnosed as having chronic pulpitis, and 14
 as having pulp necrosis that responded negative to hot and cold tests; and, clinically, all
 pulps were conﬁrmed to be necrotic on entrance into the pulp chamber. Informed consent was
 obtained and written by the parents from each patient in accordance with the approval of the
 study by the ethical board of the Universidad Autónoma de Baja California, Facultad de
 Odontología Tijuana, México. All clinical procedures and measurements were conducted by the
 author.

 A #0 periapical radiograph was taken for each tooth in buccolingual projection to allow
 proper selection. The selected teeth included 7 second maxillary molars (three canals each),
 9 first maxillary molars (2 canals each), 3 central incisors (one canal each), 18 first
 mandibular molars (2 canals each), 8 second mandibular molars (three canals each) for a total
 of 45 teeth with 102 canals.

 A standard session time recommended by the pedodontists was approximately 20-35 minutes in
 length to allow for acceptable time for completion of treatment. All treatment was performed
 by the author. As a novel treatment in Pedodontics, were included electronic apex locator
 (EAL), EndoVac system and two rotary systems: LightSpeed LSX instruments and ProTaper Next.

 The teeth were randomly divided into 3 groups (each tooth was considered as an experimental
 unit): Control Group (n= 15): the root canals were prepared manually with K-files
 (Dentsply-Maillefer, Ballaigues, Switzerland) and "step back technique" up to size #35.

 Group 1 (n= 15): the root canals were instrumented with rotary LightSpeed LSX instruments
 (Discus Dental, Culver City, CA, USA). They were used to complete the canal preparation to a
 size #50 for the anteriors and molar teeth to size #40.

 Group 2 (n= 15): root canals were instrumented with ProTaper Next (Dentsply Maillefer,
 Ballaigues, Switzerland) using X1, X2 to X3. 0.5% NaOCl was used for irrigation. The
 instrumentation time was measured for all the procedures and the results were analyzed with
 student's t-test. All statistical procedures were computed with SPSS 21.0 (SPSS Inc.,
 Chicago, IL, USA). The Student t test was used to compare data whether there were
 statistically signiﬁcant differences between the results obtained clinically. Signiﬁcance was
 set at p < 0.05.

 Pilot study. All the procedures were done in extracted primary teeth, they were prepared and
 disinfected before using the instgruments. After the debridement of the canals, the teeth
 were sectioned longitudinally and observed under microscope.

 Clinical Protocol. After local anesthesia by 2% lidocaine with 1:100,000 epinephrine (58 Rue
 du Pont de Creteil, Saint - Maur des Fossés F-94100, France) and rubber dam isolation the
 tooth was disinfected with 2.5% NaOCl (Ultra bleach, Bentonville, AR, USA).

 All caries was removed and endodontic access cavities made with sterile high speed carbide #
 331 (SS White. Lakewood, NJ). The cervical third of each canal was ﬂared with a SX ProTaper
 ﬁle (Maillefer, Ballaigues, Switzerland).

 Each canal was irrigated consequently with 2.0 cc 0.5% sodium hypochlorite. The final rinse
 was aspirated but no attempt was made to dry the canals. Working length was established with
 the Root ZX Electronic Apex Locator (J Morita, Irvine, CA) and confirmed radiographically.
 The canals were negotiated and enlarged with K-files hand instruments (Dentsply-Maillefer,
 Ballaigues, Switzerland) until reaching an ISO #20 at the working length.

 The Root ZX was used in accordance with the manufacturer's instructions. The buccal clip was
 attached to the patient's lip, and the probe was connected to a stainless steel 15 K-ﬁle. The
 ﬁle was advanced within the root canal to a point just beyond the major foramen, as indicated
 by the ﬂashing APEX bar on the liquid crystal display of the EAL.

 When the file was in position the LCD display showed a ﬂashing bar between APEX and 1.
 Measurements were considered to be correct if the instrument remained constant for at least
 4-5 seconds. A digital photograph was taken and stored in Adobe Photoshop 5.5 (Adobe Systems
 Inc., San Jose, CA, USA). The position of the file tip for each root canal were evaluated by
 two examiners, if the two examiners disagreed a third previously calibrated researcher was
 asked to make the ﬁnal decision. The ﬁnal WL was established to be 1 mm coronal to the major
 foramen (12).

 For the control group the root canals were prepared manually with K-files and "step back
 technique" up to size #35. For the Group 1, LightSpeed LSX rotary instruments (Discus Dental,
 Culver City, CA, USA) were used to complete the canal preparation to a size #50 for the
 anteriors and molars to size #40.

 For the group 2 the root canals were instrumented with ProTaper ﬁles using X1, X2 (21mm) to
 X3 (21mm). 0.5% NaOCl was used for irrigation, the original protocol suggested by ProTaper
 for permanent teeth was simplified for this study.

 After completion of canal instrumentation, all canals were irrigated with distilled water for
 30 seconds using the EndoVac irrigation system (Discus Dental, Culver City, CA, USA).

 The EndoVac system is able to apply the irrigant to working length and evacuate it using
 apical negative pressure. The negative pressure avoids forcing the irrigant beyond the apex
 into the periapical tissues.

 The canals were dried with sterile paper points and obturated at the same appointment using
 calcium hydroxide and iodoform paste (Pearson Dental, Sylmar CA) by using pluggers or
 syringes (Messing Root Canal Gun, PD, Vevey, Switzerland). Access cavities of anterior teeth
 were etched and restored with Fuji IX (GC Corp, Tokyo, Japan). For posterior teeth, a buildup
 restoration was placed by using the same etching technique and Fuji IX or temporary metallic
 crown.

 A stopwatch with alarm (http://stopwatch.onlineclock.net/) was used to record instrumentation
 time for each group.

 Children were recalled for clinical and radiographic examinations were evaluated, based on
 the criteria of Coll and Sadrian at 6-month intervals for a follow-up period of 2 years.
 Teeth that exhibited no symptoms of pain, tenderness to percussion, swelling, sinus tract, or
 pathological mobility were judged clinically successful (42 teeth).

 Teeth that showed no evidence of periradicular or interradicular radiolucency, internal or
 external root resorption, or periodontal ligament space widening were judged raiographically
 successful. Radiographic evidence of pulp canal obliteration was noted, but it was not
 regarded as failure.
Inclusion Criteria:

 -  the aims and requirements of the study were freely accepted by the parents

 -  primary molars with at least 11.0 ± 1.0 mm of working length

 -  Treatment was limited to patients in good health;

 -  All teeth had vital and non-vital pulps without a sinus tract;

 -  Excess of bleeding during a pulpotomy;

 -  Presence of enough coronal tooth and root structure;

 -  No prior pulpectomy treatment on the involved tooth,

 -  absence of perforation in the internal and/or external furcation area and

 -  No analgesics or antibiotics were used before the clinical procedures began.

 Exclusion Criteria:

 -  patients without inclusion requirements or failure to obtain parent´s authorization,
 .) patients older than 7 years old,

 -  had a positive history of antibiotic use within the past month,

 -  diabetic, hemophilic

 -  if the tooth had root resorption or been previously accessed and initiated a
 pulpectomy.