Clinical Effectiveness of Fiber-reinforced Composite Space Maintainer and Band and Loop Space Maintainer in a Pediatric Patient: A Systematic Review and Meta-analysis

Rationale

Primary dentition plays a vital role in the growth and development of the child. It aids in speech, mastication, appearance, prevention of deleterious oral habits, and guiding permanent teeth during an eruption. ¹ Premature loss of deciduous teeth leads to crowding, rotation, distal drifting of the tooth, and impaction of the permanent teeth. ^2,3

Primary teeth are considered to be the best space maintainer under normal physiological conditions. ⁴ However, in cases with premature loss of primary teeth, the best way to prevent future malocclusion would be to place an effective, affordable, and perdurable space maintainer. Space maintainers are applicable dental devices specifically designed to maintain or to create an additional space that was lost due to premature loss of primary teeth. ⁵

Various types of space maintainers can be used which depend on the dental developmental stage, dental arch involved, the number of teeth involved, location, and type of primary teeth involved. ⁶ Among all the available appliances, band and loop space maintainer (BLSM) is the most commonly used. ⁴ Qudeimat and Fayle ⁷ stated that the BLSM is economical, easy to fabricate, adapts easily, and requires less chairside time. However, it has many disadvantages like increased laboratory time, frequent dislodgement due to cement loss, increased visits and does not prevent rotation or tipping of adjacent teeth. To overcome the disadvantages of BLSM, a prefabricated BLSM were introduced. However, the only advantage it had over BLSM is that subsequent appointment for placement is not required was costlier than the latter. ⁸

Recently, a fiber-reinforced composite resin space maintainer (FRCSM) was introduced to overcome the disadvantages posed by BLSM. Fiber-reinforced composite resin space maintainers (FRCSM) are esthetic, less bulky, less time consuming, occupies less space in the oral cavity, well tolerated by the patient, does not require annual maintenance steps and physical strength is comparable to the conventional BLSM. ^9–11

There are only a few studies that attempted to compare the clinical performance of FRCSM and BLSM which were of the different follow-up period. ^8,12,13 Some of these studies favored FRCSM over BLSM while others favored BLSM. Literature has reported a wide variation in the survival rate of metal-based and resin-based space maintainers. At present, the lack of adequate evidence precludes clinicians from recommending a single best-fixed space maintainer. Therefore, there is a need for a systematic review to critically appraise and summarize the results of clinical trials evaluating the effectiveness of FRCSM, since FRCSM could be a very good alternative to BLSM.

Objective

This systematic review was planned to evaluate the clinical effectiveness of FRCSM and BLSM in pediatric patients.

Protocol and Registration

The protocol of this systematic review was registered on PROSPERO (International Prospective Register of Systematic Reviews, National Institute for Health Research) with registration number-ID-CRD42020165831. This review follows the PRISMA statement 2009.

Eligibility Criteria

The eligibility criteria of the included studies were determined scientifically with the scope of evaluating the clinical effectiveness of fiber-reinforced composite space maintainer (FRCSM). They were as follows:

• Participant/population characteristics
• Studies were conducted on children in the age-group of 3–12 years.

Inclusion Criteria

Exclusion Criteria

• Patient with abnormal dental conditions such as crossbite, open bite, and deep bite.

Intervention

• Fiber-reinforced composite space maintainer.

Control Group

• Band and loop space maintainer.

Outcome

Study Design

• Randomized controlled trials (RCTs).

Information Sources

A systematic search of major electronic databases was performed to include publications in English in the time period of 2000 to October 2020.

Electronic searches were performed in the following search engines:

• PubMed.
• Cochrane Central Register of Clinical Trials (CENTRAL).
• Google Scholar.

Search

Study Selection

Study selection and data collection were performed by two independent authors, i.e., Henpu Kamki (HK) and Hemraj Badhe (HB) and in case of any discrepancies, it was resolved by the third author, i.e., Ritesh Kalaskar (RK).

Data Collection Process

Data collection was performed using a customized data extraction form.

Data Items

Information related to the study including study design, method of randomization, description of population in terms of age and gender, sample size, details of inclusion and exclusion criteria in the study as well as the control group. The data were sorted based on the outcome and intervention. The primary outcomes for FRCSM were durability, failure rate/success rate, caries, and gingival inflammation of the abutment tooth. The primary outcome for BLSM were durability, failure rate, band slippage toward the gingival surface, caries, and gingival inflammation of abutment tooth. Secondary outcomes are a duration for fabricating appliance, patient and parental acceptance for both FRCSM and BLSM.

Risk of Bias in Individual Studies

The risk of bias in individual studies was evaluated by Cochrane collaboration’s risk of bias tool.

Summary Measures

The primary outcome of this systematic review was to assess the effectiveness of FRCSM in terms of durability, failure rate/success rate, caries, and gingival inflammation of abutment teeth. The primary outcomes for BLSM were durability, failure rate, and band slippage toward the gingival surface, caries, and gingival inflammation of the abutment tooth. Secondary outcomes were duration for fabricating appliance, patient, and parental acceptance.

Synthesis of Results

The meta-analyses were applied with RevMan 5.3 (RevMan 5.3, The Nordic Cochrane Centre, Copenhagen). Heterogeneity was assessed by a Q test and quantified with I ² statistics. Data were obtained from the included studies. Success/failure of the space maintainer was considered as the primary outcome. Comparisons between FRCSM vs BLSM were performed using the frequency of failure after 6 months and 12 months. For analysis, if the test showed substantial heterogeneity (I ² > 50%), a random-effects model was applied, or else (I ² ≤ 50%), a fixed-effects model would be used.

Study Selection

The initial search strategy yielded a total of 147 results including the studies obtained from Google Scholar. After duplication removal, articles were evaluated for their abstracts and full texts. Finally, after strict and careful application of the inclusion and exclusion criteria, eight articles were selected for the final systematic review (Flowchart 1). ^8,12–18

Risk of Bias within Studies

Risk of bias for randomized trials: Cochrane risk of bias tool for randomized controlled trials (Figs 1 and 2).

Results of Individual Studies

Results of individual studies are given in Tables 1 and 2.

Synthesis of Results

Summary of Evidence

At present, there is only one systematic review conducted by Ramakrishnan et al. assessing the survival rate of different fixed posterior space maintainers used in pediatric dentistry. They reported that there is a wide variation in the survival rate of metal-based and resin-based space maintainers and also variation existed within the metal-based space maintainers as well. Therefore, there is inadequate evidence to recommend any particular fixed space maintainer as the best due to the lack of well-designed studies. ¹⁹ Kargul et al. ²⁰ evaluated glass fiber-reinforced composite resin (FRCSM) as a fixed space maintainer in children for 12 months and found that it functions well up to 5 months. A similar conclusion was also drawn by Saravanakumar et al. ²¹ that FRCSM (Ribbond®) can be accepted over conventional BLSM for an only short period.

Quality and Design of Included Studies

To assess the quality and design of included studies, risk of bias analysis of included studies was carried out using the Cochrane risk of bias tool. Overall, a high risk of bias was observed in all the included studies. High risk was mostly due to: (a) inability to blind participants and principal investigator because of the nature of the intervention, (b) allocation concealment was not done in any of the studies, (c) random sequence generation was not reported in four studies. ^12–14,18 Moreover, the randomization method was not properly explained in four studies ^8,15–17 which led us to categorize it as an unclear risk of bias. A low risk of bias was seen in attrition and reporting bias in all the included studies. Only one study ¹⁵ performed a split-mouth design which minimized the inter-subject variability.

Characteristics of the Studied Groups

In all the clinical trials, participants were in the age-group of 4–10 years. Inclusion and exclusion criteria were similar in all the studies, except for a study conducted by Yassa et al. ¹⁵ in which cases with only premature bilateral loss of the first primary molar were included. The follow-up period for space maintainers varied from 6 to 12 months. The sample size of included studies mostly ranged from 20–30. The criteria used for evaluating the effectiveness of both SM were distortion/debonding at the enamel-composite interface, cement loss/debonding at the fiber-composite interface, fracture loop/fracture fiber framework, caries, and gingival inflammation. ^8,12–18

Assessment of Individual Space Maintainers

Band and Loop Space Maintainer

Band and loop space maintainer exhibited higher survival rate in three of the included studies, ^8,16,17 whereas one study reported a similar failure rate for both FRCSM and BLSM. ¹⁴ In this review, it was observed that the most common reason stated for the failure of the BLSM was majorly cement loss, ^{8,12,13,15–18} followed by slippage of band gingivally causing gingivitis ^12–16 and fracture of the loop. ^8,12–14,18 Distortion of the band was observed to have very less implication in failure of BLSM since it was reported in only two of the studies. ^13,14

Failure of BLSM due to cement loss might be due to various reasons, among which inadequate moisture control was the most commonly cited reason. ^8,12–18 Inadequate moisture control can lead to cement loss in glass-ionomer cement even though it has low oral solubility. ^12,13,18 Two studies ^8,14 reported that along with inadequate isolation during cementation, cement loss could also be attributed to poor band fit. Potgieter et al. ¹⁴ specifically mentioned that GIC could have led to cement loss since the ideal cement to secure bands as suggested by Croll et al. ²⁷ was zinc phosphate or polycarboxylate cement. But all the included studies used GIC for cementing the band since GIC has additional fluoride-releasing the property. Setia et al. ¹⁶ reported that though extreme care was exercised during appliance fabrication, still there might have been some failure at the band cement interface, leading to the failure of the space maintainer. The author further reported that the failure could have also been due to the non-adherence of the patient to the postoperative instructions. ¹⁶ On contrary to other included studies, Tunc et al. ¹⁷ reported only one case of cement loss. They reported that these findings could be due to differences in luting cement (GIC) and length of follow-up periods as compared to the previously conducted studies where zinc phosphate or polycarboxylate cement were used for band cementation.

The second possible reason for the failure of BLSM was due to distortion of wire. This failure could be due to bending of the loop with subsequent submerging of the wire beneath the gingiva as reported in one study. The author reported that bending of the loop may have occurred due to the intermittent functional loading on the space maintainer causing high compressive stresses on the tooth supporting the cantilever extension. This same observation was made by White et al. ²⁸ in his study. Another reason reported by the author was the extension of the loop to the deciduous canine with the absence of a rest which gave the cantilever wire a smaller contact area leading to instability of the loop. ¹⁴ Garg et al. ¹³ also reported that the reason for the distortion of wire might be because the solder wire loop lost proper contact with the non-attached abutment tooth, eventually submerging into the gingiva. This reason was also suggested by Croll ²⁷ and Kara et al. ²⁹ in their study. Also, distortion of wires might have occurred due to children fiddling with devices, as one child admitted to playing with the wire in one study. ¹⁴ This finding was in accordance with Sasa et al. ³⁰

Another reason for failure was the solder breakage (fracture of the loop). This failure may have occurred due to poor quality of construction which may either be due to an incomplete solder joint, ⁸ overheating of the wire during soldering, a remnant of flux on the wire, over thinning the wire during polishing, or failure to encase the wire in the solder. ^12,14,18

Meta-analysis

This meta-analysis combines data across studies to estimate failure rate with more precision than in a single study. The main limitation of this meta-analysis is the small number of included studies and small patient population, also the variation in the follow-up period, which could influence the results. More randomized trials would be required to increase the accuracy of the results. Meta-analysis was done for failure rate at 6 months and 12 months. It was observed that after 6 months FRCSM performed better than BLSM. ^{8,12–14,16–18} However, at the end of 12 months BLSM performed better than FRCSM. ^8,15,17,18

Strengths and Limitations

The strength of this systematic review is its complete adherence to PRISMA statement 2009. This review attempted to evaluate the effectiveness of FRCSM when compared with BLSM which has not been evaluated before. Additionally, this review only considered RCTs adding to its validity. This review also included a meta-analysis that compared the failure rate at the 6th and 12th month. The main shortcoming of this systematic review is the limited number of databases searched and the limited number of existing studies.

There is much need to conduct more RCTs with larger sample size and preferably split-mouth design since split-mouth design removes much of the inter-subject variability and can be used to check patient preferences. These studies should mainly focus on the bonding of FRCSM to the appropriate tooth surface to minimize the mechanical stresses subjected to it, in both maxillary and mandibular arch with an adequate long-term follow-up. Also, the patient should be instructed not to play with the space maintainer as this may result in inadvertent failure of the space maintainer.