Pulpotomy in caries-exposed immature permanent molars using calcium-enriched mixture cement or mineral trioxide aggregate: a randomized clinical trial.

OBJECTIVE: To compare clinical and radiographic outcomes of pulpotomy treatment using calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA) in carious-exposed vital immature permanent first molars. DESIGN: Fifty-one immature molars with clinical carious exposure with symptomatic/asymptomatic pulpitis met the inclusion criteria and randomly assigned to one of the treatment groups (CEM [26 teeth; 59 roots], MTA [25 teeth; 59 roots]). After performing pulpotomy and covering the radicular pulps with the biomaterials, all teeth were permanently restored. Blinded clinical and radiographic evaluations were performed at 6 and 12 months after operation for signs of success or failure. Radiographs were evaluated for complete/partial apical closure. The data were analysed using chi-square test and generalized estimating equation (GEE) model. RESULTS: There was no significant difference at the baseline between the two experimental groups. All available cases (49 teeth) showed pulp survival and signs of continuous root development after 12 months. Overall, complete apical closure (apexogenesis) occurred in 76.8% and 73.8% of radiographically interpreted roots in CEM cement and MTA groups, respectively. There was no statistical difference in terms of radiographic outcomes between two groups. CONCLUSIONS: Calcium-enriched mixture cement and MTA showed similar performance in pulpotomy of immature caries-exposed permanent molars.

Tongue deformation, jaw movement and muscle activity during mastication in pigs.

This study was undertaken to address the lack of information about tongue functional deformation in relation to jaw movement and muscle activity. Dimensional changes in tongue anterior and base widths, body length and base thickness were measured using six ultrasonic crystals implanted into the tongue in eight Yucatan minipigs. Jaw movements were captured on videotape and digitized, and electromyography (EMG) of tongue intrinsic (verticalis/transversus [V/T], superior and inferior longitudinalis [SL, IL]), extrinsic (genioglossus and styloglossus [GG, SG) and jaw (masseter and digastricus [MA, DI]) muscles were recorded. Signals from these three sources were synchronized. Tongue dimensions showed stereotyped and rhythmic changes during chewing cycles, with the largest changes in the body length and base thickness of the contralateral (non-working) side. The anterior tongue widened during jaw opening while the tongue base widened and thickened during jaw closing. The body lengthening accompanied base widening and ended at early power stroke, while base thickening lasted through most of the power stroke. Significant associations were found between changes of anterior width, body length and base thickness and integrated EMGs of VT, SL, SG, GG, MA and DI, but not IL. Thus, majority of tongue dimensional expansions occur during jaw closing. Intrinsic tongue muscle activities are not correlated more with tongue dimensional changes than are extrinsic tongue and jaw muscle activities.

Roles of intrinsic and extrinsic tongue muscles in feeding: electromyographic study in pigs.

The performance of tongue muscles in various feeding behaviours is not well defined. This study was undertaken to examine the role of the intrinsic and extrinsic tongue muscles during natural drinking, food ingestion and chewing. Ten 12-week-old Yucatan miniature pigs (5 in each gender) were used. Under anesthesia, fine-wire electrodes were inserted into three intrinsic (verticalis and transversus [V/T]; superior and inferior longitudinalis [SL and IL]) and two extrinsic (genioglossus [GG] and styloglossus [SG]) tongue muscles and two jaw muscles (masseter [MA] and anterior digastricus [DI]). Electromyogram (EMG) and jaw movement were recorded and synchronized when pigs were drinking water, ingesting and chewing food freely. Chewing frequency (CF), onset of activation, burst duration and integrated activity (IEMG) were assessed quantitatively, and EMG activities during drinking and ingestion were examined qualitatively. Results indicate that during chewing, the V/T and GG had one phase of activity starting at early jaw opening, and the V/T activity lasted through late of jaw closing. The SL, IL and SG had double phases with the first starting at jaw opening and the second at late jaw closing phases. The three intrinsic tongue muscles and the SG were active during 35-48% of the chewing cycle. IEMG values of the SL, IL and SG of both sides were significantly greater compared to the other muscles (p<0.05-0.01). Both the SL and the IL showed significantly higher activities in the contralateral than ipsilateral sides (p<0.05). The timing sequences of both extrinsic and intrinsic muscles were similar between ingestion and chewing, but amplitudes of the GG and IL were greatly enhanced and those of the MA and SL were reduced during ingestion. The simultaneous activation of the MA, GG and V/T were seen during drinking, along with major activity in the GG and V/T. These results suggested that the majority of activity in the intrinsic and extrinsic tongue muscles occurred during jaw opening and the occlusal phases of chewing. The activity of the GG and IL played a major role during ingestion, whereas simultaneous activation of jaw, extrinsic and intrinsic tongue muscles and major activity in the GG and V/T occurred during drinking.

Recent advancements in regenerative dentistry: A review.

Although human mouth benefits from remarkable mechanical properties, it is very susceptible to traumatic damages, exposure to microbial attacks, and congenital maladies. Since the human dentition plays a crucial role in mastication, phonation and esthetics, finding promising and more efficient strategies to reestablish its functionality in the event of disruption has been important. Dating back to antiquity, conventional dentistry has been offering evacuation, restoration, and replacement of the diseased dental tissue. However, due to the limited ability and short lifespan of traditional restorative solutions, scientists have taken advantage of current advancements in medicine to create better solutions for the oral health field and have coined it "regenerative dentistry." This new field takes advantage of the recent innovations in stem cell research, cellular and molecular biology, tissue engineering, and materials science etc. In this review, the recently known resources and approaches used for regeneration of dental and oral tissues were evaluated using the databases of Scopus and Web of Science. Scientists have used a wide range of biomaterials and scaffolds (artificial and natural), genes (with viral and non-viral vectors), stem cells (isolated from deciduous teeth, dental pulp, periodontal ligament, adipose tissue, salivary glands, and dental follicle) and growth factors (used for stimulating cell differentiation) in order to apply tissue engineering approaches to dentistry. Although they have been successful in preclinical and clinical partial regeneration of dental tissues, whole-tooth engineering still seems to be far-fetched, unless certain shortcomings are addressed.

Management of inflammatory external root resorption by using calcium-enriched mixture cement: a case report.

INTRODUCTION: Inflammatory external root resorption is one of the major complications after replantation of avulsed teeth. Here we report a case of inflammatory external root resorption in a maxillary left central incisor in an 11-year old male patient that was managed and treated by using calcium enriched mixture (CEM) cement. METHODS: The patient's chief complaint was mobility of avulsed and replanted maxillary left central incisor and pain in chewing on left central and lateral incisors. Radiographic examination showed progressive inflammatory external root resorption of the left central incisor with an inadequately obturated root canal treatment. Both teeth were immature and had periapical radiolucencies. Both teeth were irrigated copiously with 2.5% NaOCl and obturated with CEM cement. However, the central incisor was treated with calcium hydroxide 6 weeks before CEM cement obturation. RESULTS: The clinical and radiographic examinations at 3-, 6-, 12-, 24-, and 40-month follow-up showed that treated teeth were functional with normal mobility, the progression of the inflammatory external root resorption ceased, the resorptive lacunae were filled with newly formed bone, and periapical radiolucencies healed. CONCLUSIONS: Considering the biological properties of CEM cement, especially its alkalinity and sustained calcium hydroxide release, using this novel cement for treatment of inflammatory external root resorption and obturation of immature necrotic teeth might be an applicable choice.

Regenerative endodontic treatment (revascularization) for necrotic immature permanent molars: a review and report of two cases with a new biomaterial.

INTRODUCTION: Revascularization is a valuable treatment in immature necrotic teeth that allows the continuation of root development. In this article we describe successful revascularization treatment of 2 necrotic immature first mandibular molars. METHODS: The clinical and radiographic examinations showed extensive coronal caries, immature roots, and periapical radiolucencies in mandibular first molars of a 9-year-old boy and an 8-year-old girl. The exam findings suggested revascularization treatment in both cases, which was started with irrigation of the canals by using NaOCl 5.25% for 20 minutes, followed by 3 weeks of triple antibiotic (metronidazole, ciprofloxacin, and minocycline) paste dressing. Next, the antibiotic paste was removed, bleeding was induced in the canals, and calcium enriched mixture (CEM) cement was placed over blood clots. RESULTS: In radiographic and clinical follow-ups both cases were asymptomatic and functional, periapical radiolucencies were healed, and roots continued to develop. CONCLUSIONS: Revascularization is a realistic treatment in immature necrotic molars. In addition, placing CEM cement as a new endodontic biomaterial over the blood clot formed inside the canals provided good seal and favorable outcomes.