The effectiveness of using local anesthesia with general anesthesia in pediatric dental rehabilitation: a systematic review and meta-analysis

Abstract

Background

There are no established evidence-based guidelines for the administration of intraoperative local anesthesia (LA) during dental rehabilitation under general anesthesia (GA). This systematic review aims to evaluate the effects of intraoperative LA on physiological parameters and pain control in children undergoing GA for comprehensive dental treatment.

Methods

Comprehensive search was conducted across four electronic databases: PubMed, Cochrane Central Register of Controlled Trials, EBSCO, and Scopus. Search strategy was structured, yielding 14 articles that follow the study inclusion criteria. Risk of bias was performed using Cochrane Collaboration's tool for randomized trials and confidence of recommendation according to Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). Whenever there were sufficient studies with comparable data, meta-analysis was performed.

Results

Pain levels were significantly lower in the LA group compared to controls (OR = 0.32, 95% CI 0.14–0.70, P = 0.005). Lip and/or cheek biting occurred more frequently in the LA group, though this difference was not statistically significant. Although reductions were observed in physiological parameters, only the decrease in end-tidal CO₂ volume reached statistical significance (P = 0.02). The included studies were rated as having low confidence and quality based on the GRADE assessment.

Conclusion

While the intraoperative use of LA under GA reduced postoperative pain and end-tidal CO₂ volume, other effects were negligible, making its routine use optional. Evidence suggests targeting LA for high-pain procedures, such as multiple extractions, while exercising caution or withholding it during deep sedation to mitigate potential drops in tidal volume.

Systematic review registration

PROSPERO CRD42022340846

Supplementary Information

The online version contains supplementary material available at 10.1186/s13643-026-03181-2.

Introduction

Most children can undergo dental treatment in a conventional setting utilizing various behavior management strategies. However, in complex or challenging cases, advanced behavior management techniques such as general anesthesia (GA) offer effective alternatives for dental care. Examples of such cases include children with significant anxiety, extensive treatment needs, early age, and/or physical/mental challenges [1, 2].

The advantage of GA therapy lies in its ability to complete all necessary treatment in a single session, minimizing stress for the patient, parent, and dentist. It is particularly beneficial for children that are medically compromised and those that need rapid intervention in a short period of time, especially for those who might require extensive work [3]. Despite its benefits, GA is often viewed as a last-resort option due to its high cost, risk–benefit analysis, and parental acceptance [4].

Furthermore, GA causes physiological changes affecting cardiovascular, respiratory, and neural systems [5]. These changes can be further compounded by comprehensive dental treatments. Invasive dental procedures, such as administration of anesthesia and tooth extractions, can lead to significant physiological effects, including alterations in respiratory rate, heart rate, and blood pressure [6, 7]. Additionally, factors such as medication interactions and duration of anesthesia can also contribute to these physiological changes, highlighting the importance of careful monitoring during and after treatment [8].

In addition, post-operative discomfort and pain is a most common consequence of complete dental rehabilitation [9]. Studies reported that GA can be an additional source of post-operative discomfort. Intubation causes sore throats in 27% of pediatric patients [10, 11]. The majority of patients reported distresses as a result of undergoing dental treatment under GA. This discomfort is reinforced by the dental comprehensive procedures. Studies reported that children may experience pain following GA for dental restorations, stainless steel crowns (SSCs), pulpotomies, and extractions, with pain intensity increasing with the number of procedures [4, 11–13]. A significant portion experiences moderate-to-severe pain following dental surgery [10].

Current pain theories and research suggest that the use of local anesthesia (LA) during general surgeries can aid in post-operative pain control and prevent activation of deep pain pathways [14–16]. Studies on procedures like tonsillectomy, appendectomy, orchidopexy, and hypospadias repair have demonstrated improved post-operative comfort and recovery with intraoperative LA use [16]. It was also reported to increase the quality of recovery [17]. LA provides pain relief for about 2-h post-operatively that was described to be better than systemic analgesia [18, 19]. In addition, it was reported to have other potential benefits such as hemorrhage control [14]. On the other hand, other studies found that the use of LA in children undergoing oral rehabilitation under GA did not affect post-operative pain [18, 19] and could even increase post-operative dizziness [20] distress [21]; causing excessive dribbling due to unfamiliar numbness sensation and inadvertent lip biting [21, 22].

However, the use of LA in conjunction with GA remains a topic of debate in the literature. Conflict of reports and limited studies on LA use during dental rehabilitation under GA [23, 24] warrant the need for established evidence. This systematic review aims to review the literature on the effect of intraoperative LA on physiological parameters and pain control in children undergoing GA for comprehensive dental treatment. The research question driving this review is: “Does the use of intraoperative LA have a positive impact on pain control and physiological parameters following GA for comprehensive dental treatment in children?”

This review seeks to clarify the role of intraoperative LA during GA for pediatric dental procedures, aiming to provide evidence-based insights that could enhance pain management strategies and improve overall patient care in pediatric dentistry.

Methods

Protocol and registration

This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [25, 26]. The protocol was registered on June 30th, 2022, in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42022340846).

Information sources and search strategy

We conducted a comprehensive search across four electronic databases: PubMed, Cochrane Central Register of Controlled Trials, EBSCO, and Scopus. The search had no limit constraint regarding publication time up to (September 15, 2024) and no restriction on publication language. A complete search query was constructed using Medical Subject Headings (MeSH) keywords “Anesthesia, General; Anesthesia, Local; Anesthetics, Local; Dental Care; Epinephrine; Intraoperative Care Pain, Post-operative; Post-operative Hemorrhage; physiologic parameter; Randomized Controlled Trials; Adolescent; Child; Humans”. The EndNote reference manager (EndNote® version 9, Niles Software, USA) was used to detect and eliminate repeated studies.

Eligibility criteria

We employed the PICOS framework—Population, Intervention, Comparison, Outcomes, and Study Design—to establish our eligibility criteria.

• Population: participants younger than 17 years old at the start of therapy who underwent any dental treatment, including fillings, pulp therapy, or tooth extraction under GA.

• Intervention: active intervention: any LA (including type/dose/method) given during dental treatment under GA.

• Comparison: placebo or no LA or another LA prescription, including different types, doses, or methods.

• Outcomes: pain control (post-operative pain or distress measurements whether stated as pain severity, presence or absence of pain, or both), and physiological changes (Intraoperative or post-operative bleeding or physiological parameters, including heart rate, respiratory rate, and/or end-tidal CO₂ or analgesic requirement after GA). Intraoperative nociceptive responses were monitored via physiological changes, serving as objective indicators of the unconscious patients’ responses to surgical interventions.

• Study design: randomized and non-randomized clinical trials (RCTs and non-RCTs) with at least two trial arms comparing intraoperative LA for intraoperative pain and post-operative pain and other sequelae of dental treatment performed under GA. Trials comparing active LA intervention with placebo or no treatment and trials directly comparing one active LA intervention with another were eligible for inclusion.

Studies that did not have a pre-specified control group, conducted procedures other than dental or carried out on adults (over 18 years old) or medically compromised patients were excluded from this review.

Study selection and data extraction

Two authors (DJ and DA) independently assessed titles and abstracts for inclusion in the review, resolving disagreements by discussion with an expert (HS). The full text of the potentially relevant reports was retrieved and examined for eligibility according to the inclusion criteria. Additionally, a hand search of reference lists from identified published work for potential studies was eligible for inclusion. We attempted email correspondence with investigators to clarify study eligibility where primary studies did not report information, or it was unclear. We made final decisions on study inclusion through discussion and consensus.

Quality assessment and bias risk assessment

To assess the risk of bias in each included RCT, two authors used the Cochrane Collaboration's tool Review Manager (RevMan 8.12.0) [27]. Furthermore, the Consolidated Standards of Reporting Trials (CONSORT) checklist was used to assess the quality of reporting. The review authors undertook this independently and in duplicate as part of the data extraction process. The following domains were assessed: sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessor, incomplete outcome data, selective reporting, and other sources of bias. These domains were analyzed for each study and categorized as low risk of bias, high risk of bias, or unclear (some concerns bias).

Furthermore, we created a table describing the 27 items of the CONSORT checklist for each included study. We marked each study following previous systematic reviews [28, 29] as low-quality from 1 to 9; moderate-quality from 10 to 18; and high-quality from 19 to 27 of reporting. In the domain of blinding of participants and personnel, we based our judgment solely on the blinding of the participant. As the studies included were likely to include no treatment as a comparator, we could not see how personnel could be blinded in such a trial. Furthermore, we judged the lack of blinding of personnel to have a limited impact on performance bias.

The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was utilized to evaluate the certainty of the evidence and the strength of recommendations. Each research question was assessed across five established domains: risk of bias, inconsistency, indirectness, imprecision, and publication bias. Following the GRADE criteria, the evidence was categorized into four levels (high, moderate, low, or very low). Any serious study limitations or inconsistencies across the included trials resulted in a downgrade of the overall certainty of the evidence.

Data synthesis

Descriptive data was collected by three reviewers from the eligible manuscripts (DJ, DA, and AZ) and discussed with the expert (HS). The study setting, the number and age of children involved, the type of dental treatment performed, the amount and type of pain relief medications administered, and the various measured outcomes were organized and tabulated. Subgroup analyses comprised the following factors: (1) Age groups: 0–5 years, 6–9 years, and 10–16 years. (2) Types of LA utilized: lignocaine, articaine, prilocaine, or other alternatives. (3) Techniques for LA administration: infiltration, block, or intraligamental. (4) Extent of dental procedure: number of necessary extractions or restorations. Our primary analyses included all studies, regardless of their risk of bias. When two studies compared similar treatments and reported the same outcomes at the same time, one of the studies was excluded. For quantitative synthesis, at least two or more studies using the same assessment tool should be present. The software Revman, version 5, was used for the meta-analysis. Clinical heterogeneity was evaluated using Cochran's Q test, defined by the Nordic Cochrane Centre and the Cochrane Collaboration. To examine statistical heterogeneity, we planned to employ the Chi-square test to determine the presence of heterogeneity and the I² statistic to quantify the percentage of variability in effect estimates attributed to heterogeneity rather than sampling error. Pooled studies with a > 25% to 75% heterogeneity were considered low to moderate heterogeneity. A random effect model was applied in the presence of heterogeneity and fixed model when the heterogeneity scored zero. The threshold for a statistically significant P value was set at 0.05.

Subgrouping in the forest plots was based on the outcome measurements (pain and physiological parameter) and type of operative procedure. Our objective was to assess the impact of certain factors on the outcomes of the intervention. Funnel plots were used to assess precision and the possibility of minor study effects.

Results

Study selection

Our search of articles published up to August 6th 2024 yielded a total of 680 hits from three search engines: PubMed/MEDLINE (344), Cochrane (148), and Scopus (21), EBSCO (42). A total of 401 hits were obtained from the electronic search after duplicates were removed. After screening abstracts, 60 articles were selected for full-text assessment (Fig. 1). Two hundred and seventy-four articles were irrelevant and therefore excluded. One hundred and twenty-seven abstracts were reviewed, and 67 studies were excluded due to not meeting the inclusion criteria. Sixty studies were assessed for eligibility with their references, and 47 reports were excluded because they did not fulfill the eligibility criteria. From the references list of the articles, one thesis was also included in this review [30]. After a thorough evaluation, 14 studies followed the inclusion criteria and were included in this systematic review.

Fig. 1.

PRISMA Flow diagram of study selection process

Characteristics of the study setting and participants

Design of the included studies was parallel-group controlled trials that examined the effects of LA during and after surgery and the side effects of GA-assisted dental care. Out of the 14 included studies, two studies compared two active LA interventions [18], while the remaining ten compared an active intervention to a placebo [16] or no treatment [9, 17, 19, 21, 23, 30–36].

The studies involved children age ranging from 2 to 17 years. The number of children randomized in the 14 studies ranged from 9 to 142 child [16, 30]. The range of dental care provided under GA includes rubber dam placement [30, 36], extractions [16–19, 21, 23, 32–35], crowns [9, 30, 35], and pulpotomy [36, 37]. The majority of studies involved dental extractions of primary teeth.

Characteristics of the intervention and outcome

Lidocaine was used as the LA agent in 5 studies [9, 30, 32, 33, 35]; Lignocaine was used in 3 studies [16, 18, 21]. Also, Xylocaine [36], Prilocaine [34], Mepivacaine [19], and Bupivacaine [23] were used in the other. All the studies used epinephrine as the vasoconstrictor.

The studies employed various methods to assess pain. Pain was measured using multiple scales, including the Visual Analog Scale (VAS) [23, 34], Wong-Baker FACES [17, 35], and the CHEOPS scale [33]. Additionally, three studies utilized the FLACC scale [9, 30, 35]. Assessments were conducted at different time points: at waking (all studies), on discharge [16, 34] and post-discharge [16, 19, 35]. Studies found no significant differences between cases and controls in pain reduction except for two studies [9, 18].

The extent of post-operative bleeding was evaluated in two studies [21, 33]. There was a statistically significant difference between the cases and controls, with significantly longer bleeding time in the control group P = 0.001 [21] and P = 0.02 [33].

As for the assessment of patient distress, Noble et al. (1994) utilized a distress scale of 4-point Likert scale to measure levels of distress both on waking and before discharge [34]. Al-Bahlani et al. (2001) employed the Total Pain and Psychological Pain Scale (TPPPS) post-operative [21]. Coulthard et al. (2006) measured distress using a 5-category scale of behavior distress at two specific intervals: on waking and again 30-min post-intervention [16]. Finally, Townsend et al. (2009) assessed distress without specifying the method used nor the time points [35]. Out of the four studies that assess distress, two studies found a statistically significant reduction of distress when using LA in patients under GA P = 0.007 [34] P < 0.001 [21].

Post-operative anxiety was assessed in two studies using the Venham Picture Scale [31, 32]. Out of them, one study reported a significant decrease of the Venham median score in cases compared to controls (P = 0.003) [32].

In addition, two studies assist lip and cheek biting [16, 35]. Both studies reported no significant differences between cases and controls.

Physiological measures (mean end-tidal CO₂, mean heart rate, mean respiratory rate) were assisted in three studied [30, 36, 37]. El Batawi et al. (2014) found significant differences in tidal CO2 at the pretreatment period (P = 0.0006) [37]. In Skarda’s study (2021), significant differences were found in mean heart rate (P = 0.02) and mean end-tidal CO₂ (P = 0.01) [30]. A summary of the included studies can be found in Tables 1, 2, and 3.

Table 1.

Chronological overview of the characteristics of the included studies

Study	Sample size	Cases	Control	Procedure type	Measurements variables (tool)	Case	Control	P value
Pain
Noble et al., (1994) [34]	N = 100	LA (3% Prilocaine with felypressin 0.03 U/mL) n = 57	No LA (−ve) n = 43	Extracted (#1 ≥ Tooth)	VAS mean ± SD	23 ± NR	18 ± NR	0.46
Jürgens et al., (2003) [18]	N = 72	LA (2% lignocaine) N = 50	IV and/or oral analgesics a n = 22	Extractions (# any teeth)	Yes/no % Post-operative	4/50 (8%)	6/22 (27%)	> 0.05
Anand et al., (2005) [23]	Split mouth N = 30	LA (0.5% bupivacaine with 1:200,000 epinephrine) n = 30	No LA (−ve) n = 30	Extractions (permanent molar)	VAS 0–100 median (range) Post-operative Maxilla Mandible	18 (10–39) 20 (5–45)	29 (11–50) 30 (12–50)	0.33 0.29
Coulthard et al., (2006) [16]	N = 140	LA (2% lidocaine—epinephrine) n = 70	Saline intraoral injection n = 69	Extractions (1–10 teeth)	“mean ± SD” (5-face scale) Pre-operative Post-operative 30 min	0.06 ± 0.24 1.45 ± 1.38 1.74 ± 1.44	0.10 ± 0.43 1.37 ± 1.32 1.70 ± 1.32	Not mentioned 0.72 0.63
McWilliams et al., 2007 [33]	N = 85	LA (4% lidocaine—epinephrine) n = 45	No LA (−ve) n = 40	Extraction (primary molars)	CHEOPS median (range) Post-operative	6 (0–11)	6 (0–13)	0.99
Leong et al., (2007) [32]	N = 52	LA (2% lidocaine with 80:000 epinephrine) n = 36 Infiltration n = 17 Intraligamental n = 19	No LA (−ve) n = 18	Extractions (# any teeth)	Pain/discomfort STPPS mean ± SD Post-operative Infiltration Intraligamental	4 ± 3.8–5.0 4 ± 3.8–5.0	4 ± 2.5–4.0 4 ± 2.5–5	0.32
Sammons et al,.(2007) [17]	N = 86	LA(2% lignocaine) n = 42	No LA (−ve) n = 44	Extraction	TPPPS median (range) Wong-Baker FACES) Median (range) Post-operative 5 min score 15 min score 30 min score 60 min score	3 (0 −7.5) 0 (0–1) 1 (0–4) 0 (0–2) 0 (0–0)	3 (0–10) 0 (0–5) 1 (0–4) 0 (0–3) 0 (0–0)	0.42 0.023 0.904 0.797 0.763
Townsend et al., (2009) [35]	N = 27	LA (2% with 1:100,000 epinephrine) n = 15	No LA (−ve) n = 12	≥ 2-fillings, 2-anterior extractions, 4-crown/side	FLACC mean ± SD (On-discharge) Wong-Baker FACES®	2.47 ± 69 0.30 ± 0.21	2.58 ± 2.54 0.60 ± 1.35	0.88 0.92
Moness et al., (2019) [19]	N = 96	LA 3% mepivacaine hydrochloriden n = 46	No LA (−ve) n = 50	Group A: only restorative treatment (case = 24, control = 24) Group B: restorative and extraction (case = 22, control = 26)	UPAT: seven pain scores (mean ± SD) Pre-operative Post-operative After-discharge Pre-operative Post-operative After-discharge	7.63 ± 0.82 4.29 ± 0.75 1.63 ± 0.71 7.50 ± 0.74 4.18 ± 66 1.50 ± 0.60	7.67 ± 0.92 4.25 ± 68 1.50 ± 0.59 7.69 ± 0.88 4.15 ± 0.73 1.42 ± 0.64	Not mentioned
Lipp et al., (2021) [9]	N = 88	LA (2% lidocaine with 1:100,000 epinephrine) n = 43	No LA (−ve) n = 45	Comprehensive treatment	FLACC Yes/no (FLACC ≥ 1 (%)) Post-operative Moderate/severe pain (FLACC ≥ 4 (%)) Post-operative	7/43 (16%) 4/43 (9.3%)	15/45 (33.3%) 10/45 (22.2%)	0.02 0.23
Skarda (2021) [30]	N = 9	LA (2% lidocaine-epinephrine) n = 5	No LA (−ve) n = 4	Rubber dam, SSC and space maintainer	Yes/no (%) Parental report FLACC median (range) Baseline Post-operative PPPM Post-operative	2/5 (40%) 0 (0–2) 0 (0–4) 5 (3–7)	3/4 (75%) 0 (0–1) 1.5 (1–4) 3 (3–7)	0.73 0.65 0.90 0.74
Bleeding
Al-Bahlani et al., (2001) [21]	N = 100	LA (2% lignocaine—epinephrine) n = 50	No LA (−ve) n = 50	Extraction	Assessment of Hg/blood collected amount using an estimation formula mean ± SD	0.79 ± 0.06	1.19 ± 0.10	0.001
McWilliams et al., 2007 [33]	N = 85	LA (4% lidocaine—epinephrine) n = 45	No LA (−ve) n = 40	Extraction (primary molars)	4-Assessment-needs-questions on: -suctioning of bleeding, -change the dentalPads, -reassess the child for bleeding -further operation to control bleeding	1/45 (2.22%)	7/40 (17.5%)	0.02
Distress
Noble et al., (1994) [34]	N = 100	LA (3% prilocaine with felypressin 0.03 U/mL) n = 57	No LA (−ve) n = 43	Extracted (#1 ≥ Tooth)	Distress scale (4-point Likert scale, grouping no with 1 score) (on waking = on discharge)	14 (24%)	22 (51%)	0.007
Al-Bahlani et al., (2001) [21]	N = 100	LA (2% lignocaine—epinephrine) n = 50	No LA (−ve) n = 50	Extraction	TPPPS mean ± SD Post-operative	63.93 ± NR	37.07 ± NR	< 0.001
Coulthard et al., (2006) [16]	N = 142	LA (2% lignocaine—epinephrine) n = 70	Saline intraoral injection n = 71	Extraction of 1 to 10 teeth	Distress using a five-category scale of behavioral distress Pre-operative Post-operative 30 min	2.07 ± 0.27 2.24 ± 0.87 2.57 ± 0.83	2.12 ± 0.45 2.24 ± 0.87 2.42 ± 0.74	Not mentioned 0.72 0.63
Townsend et al., (2009) [35]	N = 27	LA (2% with 1:100,000 epinephrine) n = 15	No LA (−ve) n = 12	≥ 2-fillings, 2-anterior extractions, 4-crown/side	Parental negative Comments on the child’s behavior (yes/no) Post-discharge	3/15 (20%)	0/12 (0)	0.09
Anxiety
Anand et al., (2005) [23]	Split mouth N = 30	LA (0.5% bupivacaine with 1:200,000 epinephrine) n = 30	No LA (−ve) n = 30	Extractions (permanent molar)	Venham Scale/median (range) (mean ± SD) Pre-operative Post-operative	2 (0–3) 2 (0–2) (2 ± 0.33)	1 (0–3) 3 (0–5) (3 ± 0.98)	0.74 0.18
Leong et al., (2007) [32]	N = 52	LA (2% lidocaine with 80:000 epinephrine) n = 36 Infiltration n = 17 Intraligamental n = 19	No LA (−ve) n = 18	Extractions (# any teeth)	Venham Scale/median (range) (mean ± SD) Infiltration Pre-operative Post-operative (15 min) Inter-ligmanetal Pre-operative Post-operative (15 min)	2 (0–5.5) 5 (1.5–9) (5 ± 2.17) 2.5 (5–5.8) 9 (5.3–9)	3 (0.5–7) 7 (4–9) (7 ± 1.15)	0.003 0.02
Lip and/or cheek biting
Coulthard et al., (2006) [16]	N = 140	LA (2% lidocaine—epinephrine) n = 70	Saline intraoral injection n = 69	Extractions (1–10 teeth)	Lip and/or cheek biting (Parents report (yes/no)) 24-h post-operatively	1/69 (1.4%)	3/70 (4.3%)	0.62
Townsend et al., (2009) [35]	N = 27	LA (2% with 1:100,000 epinephrine) n = 15	No LA (−ve) n = 12	≥ 2-fillings, 2-anterior extractions, 4-crown/side	Lip and/or cheek biting (Parents report (yes/no)) 4–6- hours post-discharge Soft tissue damage (parents report yes/no))	4/11 (36%) 2/15 (13%)	1/12 (8%) 0/18 (0%)	0.155 0.22
Vital signs
Watts et al., (2009) [36]	N = 48	LA (2% xylocaine) n = 24	No LA (−ve) n = 24	Extracted (#1 ≥ Tooth)	Mean Heart rate (bpm)
					Pre-treatment During-treatment: -Rubber dam clamp -Pulpotomy -Crown -Extraction	118.54 ± 15.80 120.38 ± 15.49 119.11 ± 18.03 121.13 ± 16.06 119.53 ± 16.50	111.58 ± 14.05 117.82 ± 14.67 117.96 ± 16.87 112.96 ± 14.35 124.38 ± 16.45	Not mentioned
					Mean Respiratory rate (bpm)			Not mentioned
					Pre-treatment During-treatment: -Rubber dam clamp -Pulpotomy -Crown -Extraction	30.58 ± 5.69 30.96 ± 5.82 32.63 ± 7.17 30.30 ± 6.09 30.33 ± 5.08	29.92 ± 5.12 30.41 ± 5.47 33.88 ± 6.85 30.00 ± 6.26 32.08 ± 5.50	Not mentioned
					Mean End tidal CO2 (mm Hg)			Not mentioned 0.004
					Pre-treatment During-treatment: -Rubber dam clamp -Pulpotomy -Crown -Extraction	50.54 ± 3.55 50.88 ± 3.39 50.26 ± 3.46 50.96 ± 3.97 50.2 ± 3.55	51.42 ± 3.08 49.82 ± 3.49 50.24 ± 4.15 51.25 ± 3.61 47.46 ± 4.16
El Batawi et al., (2014) [37]	N = 80	LA (2% lidocaine with epinephrine) n = 40 Combined with: Extraction: Intra-ligamental Pulpotomies: Intra-pulpal 3% lidocaine Cavity preparation infiltration:	No LA (−ve) n = 40	Comprehensive dental treatment	Mean Heart rate (bpm)
					Pre-treatment During-treatment: cavity preparation Extraction Vital pulpotomies	99.3 ± 2.4 99.6 ± 2.2 101.7 ± 3.5 103.1 ± 2.1	98.3 ± 2.8 106.5 ± 1.9 117.7 ± 6.0 119.8 ± 2.4	0.089 3.70 1.15 1.03
					Mean Respiratory rate (rr)
					Pre-treatment During-treatment: cavity preparation Extraction vital pulpotomies	26.0 ± 1.4 26.4 ± 1.0 27.0 ± 1.3 27.6 ± 0.9	25.6 ± 1.7 28.0 ± 1.0 31.5 ± 0.8 31.5 ± 0.9	0.23 1.25 2.09 1.97
					Mean tidal Co2 (mm Hg)
					Pre-treatment During-treatment: cavity preparation Extraction Vital pulpotomies	40.0 ± 1.0 40.2 ± 0.8 39.3 ± 1.0 39.7 ± 0.9	39.2 ± 1.1 41.2 ± 8.4 36.0 ± 1.1 35.7 ± 0.9	0.0006 0.45 2.57 3.08
Skarda (2021) [30]	N = 9	LA (2% lidocaine-epinephrine) n = 5	No LA (−ve) n = 4	Rubber dam, SSC and space maintainer	Procedure time min, median (range)	98 (85–118)	63 (57.5–71.5)	0.0275
					Heart rate ppm, median (range)	113.91 (1.96)	123.36 (2.26)	0.0205
					Respiratory rate bpm, median (range)	22.13 (1.01)	22.11 (1.16)	0.9904
					End tidal CO2 mm Hg, median (range)	42.56 (0.69)	46.01 (0.8)	0.0197
					Systolic BP median (range)	88.96 (1.05)	88.44 (1.21)	0.7638
					Diastolic BP median (range)	39.62 (1.06)	38.68 (1.23)	0.5965

Abbreviations: LA local anesthesia, IV intra venous, VAS visual analogue scale, NR not reported, CHEOPS Children’s Hospital of Eastern Ontario Pain Scale, STPPS Simplified Toddler Preschooler‐Postoperative pain scale, FLACC Faces Legs Activity Crying Consolability assessment tool, PPPM Parental Post-Operative Pain Measure, UPAT universal pain assessment tool, Parent’s Post-Operative Pain Measure, TPPPS Toddler Preschooler‐Postoperative pain scale system, bpm pulse per minute, CO₂ carbon dioxide, BP blood pressure, NR not recorded, −ve” negative control, SSC stainless steel crown

Table 2.

Cochrane’s risk of bias assessment summary for randomized clinical trials [9, 16, 19, 21, 23, 32–36]

Table 3.

Results of meta-analysis subgrouping

Subgroups	Mean difference; P value (95% CI)	Heterogeneity I 2
Pain after comprehensive treatment	P = 0.005 (0.14 to 0.70)	0%
Anxiety with extraction using Venham Scale	P = 0.17 (− 1.59 to 0.27)	61%
Lip and/or cheek biting with extractions	P = 0.82 (− 0.08 to 25.39)	67%
Heart rate	− 1.67; P = 0.07 (− 3.46 to 0.12)	97%
Respiratory rate	− 1.13; P = 0.07 (− 2.35 to 0.09)	98%
End-tidal volume CO2	− 1.39; P = 0.02 (− 2.55 to 0.22)	96%

Abbreviation: CI confidence interval

Risk of bias in included studies

The main limitations of the included studies were in random sequence generation, allocation concealment, sample size, and investigator reliability. Overall, seven studies were categorized as “high-risk” [18, 19, 21, 33–36], three as “moderate-risk” (Anad 23, Calthout 16, Lip 9), and four as “low-risk” [17, 30, 32, 37]. Of these, all except three studies [17, 32, 37], there were issues with random sequence generation. Additionally, allocation concealment was unsatisfactory in five studies: Noble [34], Townsend [35], Jürgens [18], McWilliams [33] and Moness [19]. Blinding of outcome measurement was implemented and successfully reported in most of the studies, with the exception of four studies [18, 21, 33, 34]. Furthermore, small-study effects were measured using a funnel plot showing publication bias. Table 2 summarizes the risk of bias of included studies. Appendix 1 provides a summary of the quality results based on the CONSORT checklist.

Meta-analysis results

Meta-analysis results are shown in Figs. 2, 3, 4, 5, 6, 7 and Table 2.

Fig. 2.

Meta-analysis for studies assisting post-operative pain cases compared to control during comprehensive dental care under general anesthesia. Abbreviations: LA Local anesthesia, CI confidence interval

Fig. 3.

Meta-analysis for studies assisting post-operative anxiety case compared to control during tooth extraction under general anesthesia. Abbreviations: LA local anesthesia, SD standard deviation, CI confidence interval

Fig. 4.

Meta-analysis for studies assisting post-operative lip and/or cheek biting case compared to control after tooth extraction under general anesthesia. Abbreviations: LA local anesthesia, CI confidence interval

Fig. 5.

Meta-analysis of studies comparing heart rate case to control during comprehensive dental care under general anesthesia according to the dental procedure performed. Abbreviations: LA local anesthesia; SS stainless steel crown, SD standard deviation, CI confidence interval

Fig. 6.

Meta-analysis of studies comparing respiratory rate changes case to control during comprehensive dental care under general anesthesia. Abbreviations: LA local anesthesia, SSC stainless steel crown, SD standard deviation, CI confidence interval

Fig. 7.

Meta-analysis of studies comparing the change of CO₂ end-tidal case to control during comprehensive dental care under general anesthesia. Abbreviations: LA Local Anesthesia, SSC Stainless Steel Crown, SD standard deviation, CI confidence interval

Post-operative pain with comprehensive treatment with LA vs no LA

Figure 2 shows the forest plot for the relationship between post-operative pain after administering LA (case) compared to no LA administration (control) during comprehensive dental care under GA. After the comprehensive procedure, the pain was statistically significantly decreased in cases compared to controls (OR 0.32, 95% CI 0.14 to 0.70 and P = 0.005).

Post-operative anxiety with extraction with LA vs no LA using Venham Scale

Figure 3 shows the forest plot for the relationship between post-operative anxiety after administering LA (case) compared to no LA administration (control) during tooth extraction under GA. After extraction, the anxiety was reduced in the case compared to the control. However, this decrease is not statistically significant (mean differences − 0.66, 95% CI − 1.59 to 0.27 and P = 0.17).

Post-operative lip and/or cheek biting with extractions with LA vs no LA

Figure 4 shows the forest plot for the relationship between studies post-operative lip and/or cheek biting after administering LA (case) compared to no LA administration (control) after comprehensive dental treatment under GA. The lip and/or cheek biting was slightly increased in the cases compared to the controls. However, this increase is statistically not significant (OR 1.41, 95% CI 0.08 to 25.39; P = 0.82).

Heart rate

Figure 5 shows the forest plot for the relationship between for studies comparing mean heart rate after the administration of LA compared to no LA administration during comprehensive dental care under GA. The overall mean heart rate difference was not statistically different between cases and controls (mean difference − 1.67 and 95% CI − 3.46 to 0.12; P = 0.07). There was a decrease in heart rate after administering LA following pulpotomy (mean differences − 3.60, 95% CI − 10.88 to 3.68 and P = 0.33) and extraction (mean differences − 1.75, 95% CI − 4.63 to 1.13 and P = 0.23). There was no statistical difference when applying the LA during the SSC procedure (mean differences 0.42, 95 CI − 0.10 to 0.95 and P = 0.40.

Respiratory parameters

Figures 6 and 7 show the forest plot for the relationship between studies comparing mean respiratory rate and mean tidal CO₂ volume after the administration of LA compared to no LA administration during comprehensive dental care under GA. The overall mean respiratory rate difference was not statistically different between cases and controls (mean difference − 1.12 and 95% CI − 2.34 to 0.09 and P = 0.07). There was no statistically significant decrease in mean respiratory rate following LA application during pulpotomy (mean differences − 0.22, 95% CI − 6.26 to 1.81 and P = 0.28), extraction (mean differences − 2.22, 95% CI − 5.94 to 1.51 and P = 0.24), rubber dam (mean differences − 0.26, 95% CI − 0.78 to 0.26 and P = 0.32), and SSC (mean differences 0.02, 95% CI − 0.32 to 0.37 and P = 0.89).

A significant reduction in CO₂ end-tidal volume was observed following LA administration under GA (mean difference − 1.39 and 95% CI − 2.55 to − 0.22; P = 0.02).

Assessment of the body of the evidence by GRADE

The GRADE rating for each meta-analysis was determined by the type of the studies and its strengths. The evidence was determined to have a low overall quality. GRADE profile tables were created and presented in Appendix 2.

Discussion

The administration of LA during GA for full mouth rehabilitation in pediatric patients is a widely debated topic within the field of pediatric dentistry. While some clinicians argue that LA is unnecessary during GA, others believe that it is essential for pain management and successful treatment outcomes. This review explored various studies that evaluated the outcome when LA is given in pediatric patients undergoing full mouth rehabilitation under GA. One argument against the administration of LA is that it may increase the risk of complications. Since LA involves injecting a numbing agent into the tissues, there is a possibility of swelling, bleeding, or infection at the injection site [38]. However, full mouth rehabilitation can be an extensive and invasive treatment, involving multiple extractions, restorations, and potentially even surgeries. Without LA, pediatric patients may experience significant pain and discomfort after the procedure, which can be traumatic and lead to anxiety and dental phobia in the future.

Different types of LA were used in the included studies during GA including 3% Prilocaine with felypressin [34], 2% lignocaine [17, 18, 21], 2% lidocaine-epinephrine [9, 16, 30, 32, 33], 3% mepivacaine [19], 0.5% bupivacaine [23] and 2% xylocaine [36]. Lidocaine was the most frequently utilized anesthetic, which is expected since it is among the common medications for managing intraoperative pain in dental procedures.

In the context of postoperative pain following tooth extraction, evaluated through a binary yes/no question, there was no statistically significant difference between the LA and control in most of the studies [16, 21, 34, 35]. However, when conducting a meta-analysis between studies with similar methodologies, the relationship was significant, and the heterogeneity among studies was low (I² = 0%), demonstrating consistency in the findings. These results suggest that the administration of LA does not significantly influence the subjective experience of pain immediately after extraction when compared to the absence of LA. This difference may be attributed to the effects of general anesthesia itself, which is well known for providing considerable pain relief. Furthermore, assessing pain in young children is challenging due to their limited ability to understand assessment instructions and express their pain. Most studies in this review focused on alternative measures of pain, such as observing the child's movements or signs of distress. One method used in the studies is the FLACC pain measurement scale. Two randomized clinical trials, Townsend et al. [35] and Lipp et al. [9] investigating SSC postoperative pain using FLACC case compared to control during comprehensive dental care under GA. According to the FLACC scale, postoperative pain after LA showed significant reduction in pain when LA was used compared to non-LA groups. The primary concern that needs to be addressed is the sample size used in the studies. Furthermore, both studies showed wide confidence intervals that overlapped with the null effect, indicating substantial level of uncertainty in the results.

Some studies have assessed pain levels upon awakening or shortly thereafter, with follow-up periods varying among studies; some extended evaluations up to several days post-operative [23, 32]. Evaluating pain immediately after surgery may have presented challenges, as participants are commonly in a state of distress upon regaining consciousness, which likely reduced the sensitivity of pain assessments. Given that the majority of studies utilized short-acting LA, it remains unclear why pain was measured several hours following the procedure. Notably, Leong [32] reported that postoperative pain/discomfort and anxiety scores were not significantly different during the period of recovery. However, on the first night, the intraligamental group had significantly lower pain scores. This observation posed a challenge for explanation, especially because the LA effect had been washed out.

The heart rate showed a trend suggesting a reduction in heart rate following LA administration; however, the result did not reach statistical significance [30, 36, 37]. The borderline P-value and high heterogeneity indicate substantial variability in the effects of LA on heart rate. LA may provide some physiological relaxation, as evidenced by the reduced heart rate, but inconsistency across studies calls for more controlled investigations.

This study found a tendency towards decreased respiratory rate following LA administration; this was not statistically significant [30, 36, 37]. The non-significant result, coupled with high heterogeneity, suggests that LA’s effect on respiratory rate is variable and not robust enough to make a conclusive conclusion. Differences in patient demographics or procedural techniques might explain the variation.

Significant reduction in CO₂ end-tidal volume was observed following LA administration during GA with high heterogeneity. This finding suggests that LA could have a measurable impact on respiratory parameters, specifically CO₂ end-tidal, which reflects ventilatory efficiency [30, 36, 37]. Despite the high heterogeneity, the statistically significant reduction warrants further exploration into how LA impacts respiratory function during dental procedures under GA.

The studies included in this review exhibited clinical variation, as evidenced by variations in LA type, composition, and outcome measures. The included studies used different types of outcome measurements and periods. While some studies used self-reported or parent-reported rating scales, the Wong-Baker FACES® Pain Rating Scale [9, 30, 35], visual analogue scales (VAS) [23, 34]; others used more complex scales based on aggregating investigator scores of movement, crying, etc., such as the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) [33] or TPPPS [17, 32]. In addition, different types of LA were used during GA including 3% Prilocaine with felypressin [34], 2% lignocaine [17, 18, 21], 2% lidocaine-epinephrine [9, 16, 30, 32, 33], 3% mepivacaine [19], 0.5% bupivacaine [23] and 2% xylocaine [36].

Furthermore, the timing and dosage of supplementary analgesics varied across studies. While these analgesics were frequently administered concurrently with or shortly after the LA, specific dosages were often not reported, being standard components of the GA protocol rather than study-specific interventions. Additionally, there was variability in the timing of follow-up assessments [16, 17, 23, 32, 33, 35, 36].

In this review, it was difficult to draw a definitive conclusion on the benefits of using LA during dental treatment under GA. Due to significant differences in outcome measures, interventions, and treatment types, we encountered difficulty in combining all the included studies in a meta-analysis. The effectiveness of LA was complicated by the additional use of supplementary analgesics. However, few studies showed significant results in reducing post-operative pain [23, 34], with some reporting non-significant outcomes [16, 18, 19, 33, 35].

Confounding factors

The definition of pain addresses its subjective nature, as it is typically understood as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage” [39, 40]. Moreover, the measurement of pain itself presents inherent challenges, largely due to the difficulty of quantifying it, as pain includes both affective and sensory components. These complexities contribute to the confounding of outcomes in the studies analyzing [31, 32]. On the other hand, the utilization of pain relievers by most of the included studies while receiving GA would be regarded as standard practice, as advised by the Association of Pediatric Anesthesiologists [41]. It is scientifically reasonable that the analgesic properties of these drugs could mask any supplementary effects arising from the LA. In most of the analyzed studies, additional analgesics were administered together with the LA, either during surgery or soon after it [16, 17, 22, 23, 32, 33, 35, 36].

Quality of the evidence

The overall quality of the evidence related to outcomes such as pain, distress, bleeding, and various physiological parameters was found to be very low across all comparisons. Our assessment led to a downgrade in the quality of the evidence due to issues of inconsistency, imprecision, and potential bias. Furthermore, many of the studies reviewed were characterized by small sample sizes, and the risk of bias within the studies has further diminished our confidence in the findings. Consequently, we remain extremely uncertain regarding the effect of the LA across all four comparisons. This uncertainty indicates that the available body of evidence does not support the formulation of any robust conclusions. Therefore, despite the exploration of these outcomes, the limitations present in the studies, including their methodological variations and inherent biases, impede the ability to draw definitive recommendations. The findings highlight the need for further research with improved methodological protocols to enhance the reliability of the outcomes assessed.

Future work

Future studies should include a well-designed randomized controlled trial to quantitatively assess pain levels after full mouth rehabilitation procedures using a combination of assessment methods. Investigating patient satisfaction, anxiety levels, and recovery experiences in patients receiving combined anesthesia techniques can provide insights into the overall effectiveness of this intervention. Investigating the effectiveness of combined anesthetic techniques in different age groups could uncover variations in responses and help in tailoring anesthesia strategies to individual needs.

Strengths and limitations

Up to our knowledge, this review represents the most recent and comprehensive evaluation of the benefits of combining LA with GA in pediatric dental rehabilitation. It highlights the effectiveness of combining local and GA in pediatric dental rehabilitation, offering valuable information for practitioners. Also, the findings can inform best practices in pediatric dentistry, improving patient outcomes and procedural safety. Furthermore, this review identified areas lacking sufficient research, which can guide future studies. However, the review’s findings were constrained by the quality and quantity of published literature. The variability in the methodology of the included studies created challenges in comparing results or drawing solid conclusions. Moreover, the differences in the studies’ protocol and assessment methods across studies complicated the integration and interpretation of results.

Conclusions

While the intraoperative use of LA under GA reduced postoperative pain and end-tidal CO₂ volume, other effects were negligible, making its routine use optional. Evidence suggests targeting LA for high-pain procedures, such as multiple extractions, while exercising caution or withholding it during deep sedation to mitigate potential drops in tidal volume. Further research is needed to investigate the clinical significance of this intervention, particularly in terms of its impact on post-operative and overall patient related-outcomes.

Abbreviations

LA

Local anesthesia

GA

General anesthesia

GRADE

Grading of Recommendations, Assessment, Development, and Evaluations

SSCs

Stainless steel crowns

TPPPS

Total Pain and Psychological Pain Scale

VAS

Visual Analogue Scale

CHEOPS

Children's Hospital of Eastern Ontario Pain Scale

FLACC

Faces Legs Activity Crying Consolability assessment tool

Authors’ contributions

STI, DYJ, AYA and DAA: conceptualization, methodology and study design, investigation, data curation, formal analysis, software, project administration, supervision, writing-original draft and writing and editing final draft of the manuscript. HJS and NH: conceptualization, methodology, and study design, supervision, and writing and editing final draft of the manuscript. All authors read and approved the final manuscript.

Funding

The project was funded by KAU Endowment (WAQF) at King Abdulaziz University, Jeddah, Saudi Arabia. The authors therefore acknowledge, with thanks, WAQF and the Deanship of Scientific Research (DSR) for their technical and financial support.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.