Using AMSA and P-ASA nerve blocks for esthetic restorative dentistry.

Esthetic restorative dentistry procedures represent an increasing segment of the services provided by the general practitioner. One important assessment criterion for a successful anterior esthetic restoration is how well it harmonizes with the lips to create a pleasing smile line. Unfortunately, traditional local anesthetic techniques interfere with this assessment by distorting the lips and face during anesthesia. The anterior, middle superior alveolar block and the palatal approach anterior superior alveolar block injections represent two recently defined techniques to anesthetize maxillary teeth effectively without numbness of the face, lips, or muscles of expression. Although safety and efficacy studies are only beginning to emerge, these injections appear to be useful additions to local anesthetic techniques, especially when anterior esthetic restorative procedures are being performed.

An in vitro study of needle force penetration comparing a standard linear insertion to the new bidirectional rotation insertion technique.

OBJECTIVE: The purpose of this study was to determine the effect of a bidirectional rotation insertion technique on the force necessary to puncture and advance a needle through a tissuelike substance. METHOD AND MATERIALS: Two in vitro penetration test models were constructed using different tissuelike substances of different densities. Each tissuelike substance was tested with 30-gauge, 27-gauge, and 25-gauge needles of two brands commonly used in dentistry. The needles were placed to a standardized depth of 0.5 inch (1.27 cm) at a standardized rate of insertion. A customized dental surveyor allowed controlled forces to be applied. A linear insertion technique and a newly described bidirectional rotation insertion technique were tested. The force of puncture and penetration drag was recorded with an electronic digital scale. A total of 400 needle insertions were performed. RESULTS: A multivariate analysis of technique, material, needle gauge, and needle brand revealed the data to be statistically significant, demonstrating no overlap. The post-hoc analysis of between-subject effects found that the needle insertion technique accounted for the most powerful effect in reducing force penetration. The bidirectional insertion technique had the greatest influence on reducing the force penetration irrespective of material, needle gauge, or needle brand tested in this study. CONCLUSION: The bidirectional rotation insertion technique required two to three times less force than did a standard linear insertion technique. A continuous rotation in a single direction would be expected to produce similar results. Needle gauge and needle design have a smaller effect on reducing force penetration than did the technique used during insertion. The in vitro model used in this study represents a reliable dynamic testing system that can be used for future evaluation of needles.

Histologic response to intraligament injections using a computerized local anesthetic delivery system. A pilot study in mini-swine.

BACKGROUND: Intraligamentary (periodontal ligament) injection has been used to locally control pain with minimal anesthetic dose. The purpose of the present study was to determine the histologic effect of using a computer-controlled local anesthesia delivery system (CCLADS) for the administration of a periodontal ligament injection in the mini-swine model system. METHODS: Thirty-two sites in 3 mini-swine pigs with healthy periodontium were selected. Each site was notched on the mesial-lingual line angle of the tooth to allow a reference for needle placement and provide a histologic marker. An anesthetic cartridge was used with a 30-gauge needle attached to the handpiece of the CCLADS. This provided a controlled flow rate for 2 minutes. The control sites were treated with the same needle in place for 20 seconds. The animals were sacrificed and provided observation periods of 1 hour, 1, 4, 7, 21, and 49 days. Specimens were stained with hematoxylin and eosin and trichrome. RESULTS: Twenty-four hours after injection, limited localized inflammation was present. By 7 days, the ligament appeared within normal limits. Apical migration of the junctional epithelium extended to the apical limit of the notch and was similar in test and control specimens. CONCLUSIONS: Within the limits of this study, the histologic results showed that tissue responses following intraligament injections using a CCLADS demonstrated limited inflammatory responses within the first 24 hours, which abated by 7 days postinjection. Similar migration of the junctional epithelium was seen in test and control specimens and was probably related to tooth injury rather than anesthetic injections. Further investigations are warranted using CCLADS to determine whether clinical benefits will translate in the human model system.

In vitro study of needle deflection: a linear insertion technique versus a bidirectional rotation insertion technique.

OBJECTIVE: Deflection of dental needles during tissue penetration has been associated with a failure to achieve successful anesthesia. The purpose of this study was to determine whether needle deflection in a tissuelike substance could be minimized through the use of a bidirectional rotation insertion technique. METHOD AND MATERIALS: Three in vitro deflection test models were constructed, each incorporating a different tissuelike substance of a different density. Each substance was tested with 3 different needle sizes (30-guage, 27-gauge, and 25-gauge). A customized dental surveyor allowed for standardized needle insertions to a standardized depth of 20 mm. Two different insertion techniques, a linear insertion technique and a newly described bidirectional rotation insertion technique, were tested. Radiographic analysis was performed after each insertion. RESULTS: The bidirectional rotation insertion technique described was consistently more effective in minimizing needle shaft deflection for 30-, 27-, and 25-gauge needles. The differences were statistically significant. Each of the different tissuelike substances consistently demonstrated this reduction in needle deflection. CONCLUSION: The factor that most greatly affects the path taken by a needle through a tissuelike substance is the force vectors that act on the needle's beveled surface. The use of a bidirectional rotation insertion technique minimized needle deflection, resulting in a straighter tracking path for 30-, 27-, and 25-gauge dental needles, in 3 different tissuelike substances tested in this study.

P-ASA block injection: a new palatal technique to anesthetize maxillary anterior teeth.

UNLABELLED: This technique article presents a new local anesthetic injection that is reported to produce anesthesia of the six maxillary anterior teeth, the anterior third of the palate, and the facial gingiva from a single-site injection. The injection is referred to as the palatal approach anterior superior alveolar (P-ASA) nerve block. The 0.9 to 1.4 mL dosage recommendation for this block injection is significantly less than for a traditional supraperiosteal approach. The primary advantage of this injection is that it allows the dentist to anesthetize the teeth and gingiva without collateral anesthesia to the lips, face, or muscles of facial expression. Therefore, the smile line is not distorted during the operative phase of an appointment, and the patient is more comfortable postoperatively. CLINICAL SIGNIFICANCE: The P-ASA is a new block injection technique that provides anesthesia of the maxillary anterior teeth from a single injection without numbness of the face, lips, and muscles of facial expression. This injection technique prevents distortion of the smile line and enhances restorative procedures that use the lip line as an esthetic reference element.

The AMSA injection: a new concept for local anesthesia of maxillary teeth using a computer-controlled injection system.

This article describes a new injection technique for the maxillary arch that achieves pulpal anesthesia of the central incisor through the second premolar without collateral anesthesia of the face and muscles of expression. This palatal injection can be delivered easily, consistently, and virtually imperceptibly with a recently introduced computer-controlled local anesthesia delivery system. The anterior (AMSA) middle superior alveolar block, is a single-site injection requiring less than one cartridge of anesthetic and is ideal for maxillary esthetic restorative dentistry because it does not distort the smile line. A clinical example is also presented.

A 21st century computerized injection system for local pain control.

This article describes a new computerized local anesthetic injection system for pain control. The core technology of this system is the microprocessor-controlled delivery of anesthetic solution at a constant pressure and controlled volume, regardless of encountered variations in tissue resistance. This fine-tuned, high suffusion flow rate of anesthetic provides a rapid onset of anesthesia for most patients. Traditional block injections and infiltrations as well as palatal injections and periodontal ligament injections are administered with precision, ease, and patient comfort.