Research Demonstrates the Safety of Local Anesthesia Administration by Dental Hygienists

Part 2 of a two-part series. Part one appears in the May issue of Dimensions of Dental Hygiene available here.

Legislative update: The Texas legislature has passed a bill that allows dental hygienists to administer local anesthesia infiltration injections, which is awaiting the governor’s signature. Georgia’s governor has officially signed the bill that allows dental hygienists to administer local anesthetic injections throughout the state.

Studies published over the past half-century demonstrate that dental hygienists safely administer local anesthetic injections within the standard of care and provide outcomes similar to or better than dentists or medical providers (Table 1).^1–15 In the first pilot program designed to train dental hygienists in expanded functions, complications following anesthesia administration by dental hygienists rarely occurred.¹⁶ Of the 19,849 injections administered by dental hygienists, only three cases (0.01%) of transient paresthesia were identified with no reports of severe or permanent complications.¹⁶

More recent research evaluating adverse events associated with dental hygienists administering local anesthesia revealed minimal complication rates and no reports of severe adverse events.² An analysis of 923 consecutive patients seen by dentists and dental hygienists for local anesthetic administration within a portable pediatric dental clinic found no statistical differences in complication rates between dentists and dental hygienists.⁸ The study found that complications were rare, and the most common adverse event was self-inflicted lip soft-tissue injury (1.95%).

An evaluation was completed of intraoral administration of local anesthetics for 172 individuals with intellectual or developmental disabilities by dentists and dental hygienists.⁹ The analysis determined that local anesthesia-related adverse events were rare and that there was not a statistically significant difference with complication rates during local anesthesia administration between dentists and dental hygienists. A survey of Massachusetts dental hygienists determined that 81% of respondents administering local anesthesia had not experienced any complications during their careers.¹⁰

The absence of reported disciplinary actions has also substantiated the safety of local anesthesia administered by dental hygienists. Based on surveys reported in 1990 and 2005, there were no formal complaints related to local anesthesia administration by dental hygienists to relevant oversight agencies and/​or authorities.¹¹ From 1990 through 2022, data from the National Practitioner Data Bank (NPDB) showed only two of the 2,434 (0.08%) dental hygiene malpractice reports pertained to the administration of local anesthesia.¹²

Effectiveness

A successful patient experience with local anesthesia centers on achieving profound anesthesia to optimize comfort (Table 2).^7,10,15–21 The first experimental training program at the Forsyth School for Dental Hygienists published results demonstrating high success rates with local anesthesia by dental hygienists (96.7% for infiltration and 85.7% for nerve block injections).¹⁶ Since this study was published in the late 1970s, several publications have replicated these success rates and found the results are similar to success rates of local anesthesia administration by dentists, 90% to 100% with infiltration and 80% to 90% success with nerve block injections.^2,15,22–24

In 1986, University of Iowa dental faculty members from the restorative and periodontal departments evaluated 3,926 injections administered by dental hygiene students and found 95% were successful.¹⁷ In 2000, approximately 5 years following the implementation of local anesthesia by dental hygienists in Arkansas, 92% of 182 surveyed Arkansas-based dentist-employers believed their dental hygienists could effectively administer local anesthesia injections.¹⁸

In 2002, 76% (n=273) of Minnesota dental hygienists reported successful anesthesia 90% to 100% of the time, 16% reported success 75% to 89% of the time, 2% reported success 51% to 74%, and 6% did not respond to the question.¹⁴ An evaluation of Massachusetts dental hygienists with local anesthesia permits determined that 90.5% reported success rates above 85% with more than two-thirds reporting 95% or higher.¹⁰

An analysis of clinically active dental hygienists in Pennsylvania self-reported high success rates with local anesthesia: 95% to 100% success rate (55.9% of respondents) and 85% to 94% success rate (39.4%). Mirroring studies with dentist local anesthesia administration, infiltration injections were reported with higher success rates, and nerve block injections were associated with lower success scores.

The comfortability of dentists delegating the administration of local anesthesia to dental hygienists is well documented. A 2022 analysis of Pennsylvania dental hygienists administering local anesthesia determined that 26.9% administer injections for patients to be treated by dentists.⁷ A national prospective survey found that the majority (58.4%, n=150/⯹) of dental hygienists administering local anesthesia injections responded they have provided anesthetic injections to patients being treated by dentists.⁶ Further, regional analysis completed by these investigators determined that the practice of dental hygienists administering local anesthesia for dentists was more common in areas of the United States where dental hygienists were permitted to administer local anesthetics for the longest periods of time.

The type of practice setting also impacted whether dental hygienists provide injections for patients being treated exclusively by a dentist. A national evaluation (n=257) determined that those working within a periodontal specialty practice were the most likely to have administered local anesthesia for the dentist’s patient in the past (89.5%), followed by public health (83.3%), general dentistry (58.5%), academia (40.0%), and pediatric dentistry (20.0%).²⁵

Patient Comfort

A comfortable injection that results in low to no anxiety is a hallmark of a successful anesthesia administration.^26,27 De St. Georges²⁶ and Bulger²⁷ published prospective surveys of what patients are looking for in a dentist and why people hate the dentist. The two most significant like/​hate factors were:

Like: does not hurt and a painless injection

Hate: pain and the needle

In an analysis of 18 patients with a recent dental visit, the majority believed their dental hygienist provided a more comfortable local anesthesia injection than their dentist.¹⁵ Patient satisfaction with dental hygienists providing local anesthesia is generally positive and has been attributed to slower administration rates, attention to detail, or greater empathy.²

Operational Utilization and Efficiency

A review of primary practice areas indicates that urban counties have a greater number of dental hygienists who hold local anesthesia permits, while rural counties have a higher proportion of dental hygienists who are qualified to administer local anesthetic injections but are not currently doing so.²⁸ The dental hygienists attribute this to reasons such as their supervising dentist not considering it advantageous or a lack of perceived demand for the service.^7,28

For a procedure to be widely adopted into daily operations, a demand and value for the service must be demonstrated. Anderson¹⁴ reported that 58% of responding dentists revealed that a dental hygienist’s ability to administer local anesthesia was valuable to their practice, with 64.4% reporting their practice ran more smoothly, and 53.1% noting that dental hygienists were more thorough with treatment procedures.

In an analysis of Pennsylvania dental hygienists who administer local anesthesia, respondents strongly agreed that the ability to provide injections improved office efficiency and allowed the patient’s treatment to be more thorough.⁷

In similar findings, Cross-Poline and colleagues¹⁹ reported that most dentists identified a benefit to both their practices and their patients because of the administration of local anesthesia by dental hygienists. DeAngelis and Goral¹⁸ found that most dentists indicated that local anesthesia administration by dental hygienists produced positive effects on their practice in the form of smoother schedules, patient satisfaction and comfort, and improved productivity.

A 2011 national survey found that 59.5% (n=429) of US dental hygienists administer at least one local anesthesia injection weekly.⁶ The results demonstrated that nerve block and infiltration injections were the most administered injection techniques. The analysis also determined that dental hygienists practicing within a periodontal specialty setting were utilizing injections most often and those within pediatric specialty settings were utilizing injections the least over the course of a week. Additional studies reported similar findings with dental hygienists working in periodontal offices administering local anesthesia for three to six patients per week, while hygienists working in general practice administer local anesthesia for one or two patients per week.^2,3,6,12,17

Conclusion

A significant history of research and literature validates the frequent, safe, and effective practice of local anesthesia administration by dental hygienists. According to previous studies, dental hygienists are regularly providing local anesthesia safely and effectively, which is beneficial both to dental practices and patients. Local anesthesia education and training of dental hygienists have been standardized and feature appropriate instructional materials. In addition, there is a great deal of commonality between dental and dental hygiene local anesthesia training, regardless of location.

Given a 50-year history of safe and effective administration of local anesthetics by dental hygienists, and its widespread utilization and acceptance by experts and leading professional organizations, the administration of local anesthetics by dental hygienists has become a national standard of care.

References

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3. Gutmann ME, DeWald JP, Solomon ES, McCann AL. Dental and dental hygiene students’ attitudes in a joint local anesthesia course. Probe. 1997;31(5):165–170.
4. Teeters AN, Gurenlian JR, Freudenthal J. Educational and clinical experiences in administering local anesthesia: a study of dental and dental hygiene students in CaliforniaJ J Dent Hyg. 2018;92:40–46.
5. Johnston A. Evaluating the role of dental hygienists in the role of anesthesia and analgesia. In: Dental Anesthesia: A Guide to the Rules and Regulations of the United States. 5th ed. New York: The Orchard Publishing; 2013.
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7. Dental Medicine Consulting. Pain Management in Dentistry. Available at: dentalmedicineconsulting.c/​m/​?pa_​e_​id=1332. Accessed May 17, 2023.
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From Dimensions of Dental Hygiene. June 2023; 21(6):14-17.