Quality of Life with the Rehabilitation After Partial Mandibulectomy: a Systematic Review

Abstract

To evaluate the QoL before and after prosthetic rehabilitation of partial mandibulectomy patients based on the type of surgery, effects of radiation, the type of prosthesis, and to enlist their outcome on the rehabilitation. Literature search as per PICO format was carried out within a time range from January 2000 to June 2021. The review followed PRISMA guidelines and registered with the PROSPERO(CRD42021258472). The focus question was established as per the PICO format (Population, Intervention, Comparison, Outcome). The population involved partial mandibulectomy individuals with prosthetic rehabilitation as an intervention. The outcome, quality of life (QoL), was compared with the pre and post partial mandibulectomy patients rehabilitated with a prosthesis. The search yielded 367 articles and based on the search criteria only 7 articles were suitable for qualitative analysis. Marginal resection of the mandible is less aggressive than segmental resection which provided function, phonation, and esthetics at acceptable levels but the food mixing ability was reduced when resection is accompanied by glossectomy. However, the perceived chewing ability and OHRQoL were not accountable to the extent of surgical excision. An overall increase in the QoL on rehabilitation with acrylic prosthesis depicting satisfactory functionality with a considerable improvement in mastication, speech, and social life. QoL and Denture Satisfaction Index did not differ based on the number of implants in an implant overdenture prosthesis, but the chewing ability was improved. An increase in the number of remaining occlusal units improved the overall QoL. Restoration of the function, psychological comfort, and improvement in esthetics was significant in patients who underwent prosthetic rehabilitation. The QoL between conventional and implant prostheses was observed to be more similar, and the effect of remaining hard and soft tissue structures has a major influence on patient comfort signifying the influence of the extent of surgical excision.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-022-01664-x.

Introduction

Oral squamous cell carcinoma is the second most common cancer predominantly occurring in the lower third of the face, and in males with an incidence of 21.2 [1]. Unfortunately, most of these lesions are diagnosed late, and requires surgical resection along with adjacent anatomical structures such as the mandible, the floor of the mouth, tongue, and/or in combination with radiotherapy [2]. The composite resection involves removal of part of the mandible often crossing the midline, to permit complete excision of the tumor along with the periosteal lymphatics [3].

Hemimandibulectomy is performed restricting the resection to one side of the mandible [4]. The procedure involves resection of the affected mandible along with the condyle, teeth, salivary glands, and attached muscles, resulting in the deviation of the mandible inferiorly towards the resected side. The increased tension in the contralateral medial and lateral pterygoid muscle fibers will tend to rotate the mandible further towards the side of the resection to affect the mastication and mandibular movements [4, 5]. This deviation is further worsened by the rotation of the mandibular occlusal plane inferiorly due to the pull of suprahyoid muscles, and the loss of ligaments of the temporomandibular joint allows the mandible to fall vertically from its normal position. This results in facial disfigurement, loss of occlusal contact, lip incompetency for saliva control, and reduced ability to swallow [6, 7].

The loss of hard and soft tissue leads to speech impairment, reduced masticatory ability, swallowing, and esthetics. The unfavorable anatomy of the intraoral hard and soft tissues often constitutes insurmountable obstacles for dental rehabilitation and functional reconstruction, leading to a psychological disability affecting the patient’s quality of life (QoL) [3]. To minimize the psychological trauma associated with the facial disfigurement in partial mandibulectomy patients and improve the quality of life (QoL), four significant factors should be considered during prosthetic rehabilitation: the site and extent of surgery, effects of radiation, the presence or absence of teeth and psychological impact [4, 7]. The assessment of these functions aids in measuring the degree of deterioration, and frame a suitable prosthetic plan. The objective of the systematic review was to evaluate the QoL before and after prosthetic rehabilitation of partial mandibulectomy patients based on the type of surgery, effects of radiation, the type of prosthesis, and to enlist their outcome on the rehabilitation.

Materials and Method

The systematic review was conducted following PRISMA (updated October 2015) guidelines and was registered with the PROSPERO International prospective registry (Reference No: CRD42021258472) for systematic reviews. The focus question was established as per the PICO format (Population, Intervention, Comparison, Outcome). The population involved partial mandibulectomy individuals with prosthetic rehabilitation as an intervention. The outcome, Quality of life (QoL), was compared with the pre and post partial mandibulectomy patients rehabilitated with a prosthesis.

Eligibility Criteria

Two independent researchers performed the electronic search using MeSH keywords for PICO (Population, Intervention, Comparison, and Outcome) format with the Boolean index of AND between the components. The MeSH keywords for the population component were oral neoplasm (OR) jaw neoplasm. MeSH keywords for the intervention were prosthetic rehabilitation (OR) mandibular guiding flange (OR) maxillary palatal ramp (OR) complete denture (OR) implant-supported dental prosthesis. The above-mentioned intervention was compared with the keywords; hemimandibulectomy (OR) segmental mandibulectomy (OR) unilateral free end mandibulectomy (OR) marginal mandibulectomy. Finally, the outcome variable evaluated included Quality of Life (QoL).

Information Sources

Literature published in the time range of January 2000 to June 2021 was sought after by the three independent researchers in the following database; PubMed, Science Direct, Cochrane, IndMED, OVID, and EMBASE. The search for grey literature was carried out in the Opengray database.

Study Selection

Only prospective randomized controlled trial, cohort, case–control studies that analyzed the QoL after prosthetic rehabilitation of partial mandibulectomy individuals were included. The surgical excision that extensively involved the head and neck region, the studies that did not assess the QoL were not included.

Data Collection and Data Synthesis

The data were extracted by the first author and filled into a pre-defined form that evaluated the basic characteristics of the study. The extracted data was tabulated chronologically and were summarized based on the study design, number and the age of the patients, type of the prosthesis, duration/follow-up period, questionnaires used, and the intervention and outcome. The outcome of the hypothesis, Quality of life after prosthetic rehabilitation was evaluated based on the type of surgery, radiation exposure, number of occluding units, and the type of prosthesis (Table 1). The second author checked the information collected, and the third author settled the disagreement between the authors.

Table 1.

Summary of studies included in the systematic review

Author	Year	Study design	Demographic detail (age group; no. of participants)	Aim	Standards evaluated or tests done	Time of assessment	Comparison	Outcome
Schweyen R et al	2016	Prospective clinical study	131 patients with mean age of 57.7 years at the timing of radiotherapy (range 24 to 79 years)	Analyzed the influence of dental treatment in the OHRQoL of Post mandibular resection radiotherapy patients	OHRQoL -using OHIP G14	Completed at least 1 year after prosthetic restoration between representative normal population and hemimandibulectomy patient	None or fixed partial dentures (FPD) vs Removable partial dentures (RPD) vs full dentures (CD) in different tumor sites	Tumor site and QoL high significance. No treatment/FPD and RPD, CD patients did not differ significantly from each other. Teeth and type of denture had a limited effect on OHRQoL in head and neck cancer patients
Aimaijang Y et al	2015	Cross sectional study	38 patients (18 woman, 20 men; mean age, 69 years; age range, 38–87 years)	Assessed the association between the type of surgery and perceived chewing ability, objective masticatory function, and oral health-related QoL in patients with Dento maxillary prosthesis	Perceived chewing ability, objective masticatory function, and oral health related QoL	Patients underwent the questionnaire having worn the prosthesis for at least 6 months	Marginal mandibulectomy vs segmental mandibulectomy vs glossectomy	Objective mixing ability was found to be significantly low in only glossectomy group. Perceived chewing ability and objective mixing ability were significantly associated in the marginal mandibulectomy and glossectomy groups but not in the segmental mandibulectomy group
Kalaignan P et al	2018	Prospective clinical study	20 patients	Evaluated the oral health related Qol with mandibular resection prosthesis	OHRQoL, OFS-15, MFPPS-10	2 weeks and 3 months after prosthesis	QoL with prosthesis 2 weeks, 3 months	Overall QoL improved significantly from 2 weeks to 3 months after prosthetic rehabilitation
Karayazgan Saracoglu BK et al	2017	Prospective clinical study	22 patients with a mean age of 65.50 years	Evaluated the satisfaction and oral health related quality of life of patients with marginal mandibulectomy with implant retained overdentures and fixed metal acrylic resin prosthesis	OHIP-Edent	Before implant placement and 6 months after delivery of their implant supported prosthesis	Implant retained overdentures vs fixed metal acrylic resin prosthesis	OHIP-Edent values in overdenture prosthesis group were higher than those with a fixed metal acrylic resin prosthesis
Kumar VV et al	2016	Prospective randomized clinical trial	52 patients with mean age of 34.3 and 36.5 for Group I and II respectively	Assessed the difference in quality of life in patients with dental rehabilitation using two or four IP following segmental mandibulectomy	Qol, EORTC H&N	Baseline, 6, and 12 months after prosthesis delivery	ISP with 2 implants vs ISP with 4 implants	No significant differences in Qol between the two implant and four implant group
Fierz J et al	2013	Prospective cohort study	18 patients	Evaluated the Qol of tumor patients after surgery and prosthetic tumor rehabilitation	EORTC QLQ-C30, EORTC H&N35, general well-being, function, Oral symptoms	3 to 6 years after prosthetic rehabilitation	Prosthetic rehabilitation	Most common complaint was mouth opening, Xerostomia, and physical appearance
Sato et al	2013	Prospective clinical study	10 patients	Evaluated the effects of implant supported prostheses (ISPs) on oral health-related quality of life (OHRQoL) and chewing ability	OHRQoL was assessed using Oral Health Impact Profile (OHIP-49)	Before and 1 year after ISP placement	Prosthetic rehabilitation	ISP placement improves OHRQoL and the self-assessed masticatory ability. Moreover, the prosthesis type were not significantly affecting OHRQoL

Risk of Bias Assessment

The bias assessment for randomized controlled trials was performed using the “Revised Cochrane risk of bias tool for randomized trials (Rob2)” version of 22 August 2019 (Table 2) and the bias assessment for non-randomized controlled trial was performed using The Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) assessment tool Version 19 September 2016 (Table 3) and Newcastle–Ottawa scale (Table 4).

Table 2.

Revised Cochrane risk of bias tool for randomized trials (Rob2)

Author	Year	Risk of bias arising from the randomization process	Risk of bias due to deviations from the intended interventions	Missing outcome data	Risk of bias in measurement of the outcome	Risk of bias in selection of the reported result
Kumar VV et al	2016	Low	Low	Low	Low	Low

Table 3.

The Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) assessment tool

Author	Year	Bias due to confounding	Bias in selection of participants into the study	Bias in classification of interventions	Bias due to deviations from intended interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported result	Overall bias
Fierz J et al	2013	Low	Low	Low	Low	Low	Low	Low	Low
Aimaijang Y et al	2015	Low	Low	Low	Low	Low	Low	Low	Low
Schweyen R et al	2016	Low	Low	Low	Low	Moderate	Moderate	Low	Low
Karayazgan Saracoglu BK et al	2017	Low	Low	Low	Low	Low	Low	Low	Low
Kalaignan P et al	2018	High	High	Cannot be specified	Moderate	Moderate	High	High	High
Sato et al	2019	Low	Low	Low	Low	Low	Low	Low	Low

Table 4.

Quality assessment of included studies using Newcastle–Ottawa Scale

Author	Year	Representativeness of exposed cohort	Selection of non-exposed cohort	Ascertainment of exposure	Outcome of interest not present at beginning of study	Comparability of cohort	Assessment of outcome	Follow-up	Adequacy of follow-up
Kalaignan P et al	2018	*	–	*	*	*	*	–	–
Aimaijang Y et al	2015	**	*	**	*	**	*	*	*
Schweyen R et al	2016	**	*	**	*	**	*	*	-
Fierz J et al	2013	*	*	**	*	**	*	**	*
Sato et al	2019	*	*	**	*	**	*	**	**
Karayazgan Saracoglu BK et al	2017	**	*	**	*	**	*	**	**

Result

Study Selection

The search yielded 359 articles identified through PUBMED (121), EMBASE, OVID (231), Cochrane registry (7), and 8 Opengray literature. Two hundred forty-six duplicates were removed and the 121 articles were further analyzed by the title and abstract to check their relevance to the hypothesis. This yielded 47 articles and was further filtered for full-text availability. At the end of the structured literature search, only 7 articles were suitable for qualitative analysis based on the search criteria (Fig. 1). The meta-analysis was not performed due to heterogenicity in comparison criteria between the selected articles.

Fig. 1.

Prism flowchart

Study Characteristics

Based on the study hypothesis, 6 prospective cohort studies and 1 randomized controlled trial were evaluated. After partial mandibulectomy, a total of 83 patients were treated with conventional mandibular resection prosthesis [8, 9] and 100 patients were rehabilitated with implant-supported prosthesis [10–13]. The questionnaires that were used to assess the QoL after rehabilitation included OHIP-14, EORTC QLQ-C30, EORTC H&N35, OFS-15, and MFPPS-10 Dental Prescale 50RH System.

Qualitative Synthesis of Results

The risk of bias revealed low risk of bias for all included studies except for Kalaignan et al. (Table 2). The certainty of evidence was moderate due to heterogenicity of the collected articles even though there was low risk of bias with most of the articles.

QoL Based on the Type of Surgery

Fierz J et al. [10] proved that the QoL of surgically treated tumor patients improved after prosthetic rehabilitation. Aimaijang Y et al. [8] compared the QoL in prosthetically rehabilitated marginal mandibulectomy, segmental mandibulectomy, and glossectomy patients and suggested that the QoL was not different after rehabilitation in all the patients. However, the food mixing ability was lower in the glossectomy group. Karayazgan et al. [11] compared segmental mandibulectomy with marginal resection and stated that the marginal resection of the mandible is considered as a less aggressive and more conservative surgical procedure that provides acceptable levels of function, phonation, and esthetics improving the oral health QoL [11].

QoL Based on the Type of Prosthesis

Garrett et al. [14] determined the effectiveness of conventional and implant-supported prostheses after the surgical reconstructive procedures. He observed the patient turnover for implant prosthesis was minimal and recommended the use of implant-supported prosthesis after one year of completion of ablative surgery to avoid failure due to the recurrence that occurred during the first year. Kumar VV et al. [12] observed no significant difference in QoL on rehabilitation between two and four implants supported prosthesis after segmental mandibulectomy.

Karayazgan BK et al. [11] evaluated the satisfaction and oral health-related QoL of patients who had undergone marginal mandibulectomy followed by rehabilitation with implant-retained overdentures and fixed metal acrylic resin prosthesis. The results suggested that OHIP-Edent values in the group with an overdenture prosthesis were higher than fixed metal-acrylic resin prosthesis, denoting an improvement in the QoL.

Kalaignan P et al. [9] measured the oral health-related Qol in patients with removable mandibular resection prosthesis using the Oral Health Impact Profile (OHIP-Edent-19) and Maxillofacial Prosthesis Performance Scale (MFPPS-10) questionnaires. He suggested that the overall QoL improved significantly by 75% in patients wearing a prosthesis for a period between 2 weeks and 3 months, but the psychological discomfort (41%) after 2 weeks of the prosthesis in function was observed in more than 50% of the participants. Fierz et al. [10] stated that the prosthetic rehabilitation did not improve the oral health QoL due to compromised facial esthetics, difficulty in mouth opening, and swallowing.

Sato et al. [13] in a prospective clinical study evaluated the effects of implant-supported prostheses on OHRQoL and chewing ability. They reported that there were no significant differences in mean OHIP-49 score or self-assessed masticatory ability between the removable and fixed type of prosthesis. However, the masticatory ability increased within 1 year of prosthesis placement for both types of prosthesis, with a higher score observed in fixed prosthesis.

Qol Based on Radiation and Prosthodontic Rehabilitation

Kumar et al. [12] rehabilitated patients with the prosthesis 1-year post-radiotherapy and observed poor QoL in 8 out of 48 domains. Karayazgan et al. [11] selected patients for rehabilitation after 5 years of radiation exposure and observed an improvement in their quality of life. Fierz et al. [10] observed that the complications were more with implant treatment on individuals who had received radiotherapy. He concluded that an implant-supported prosthesis was a better treatment modality than the mucosal-supported prosthesis due to post-radiotherapy complications such as xerostomia and mucosal irritation that deters the retention of the mucosal supported prosthesis. Schweyen et al. [15] had also observed the QoL to be decreased in radiation-exposed individuals than the non-radiated individuals, though the radiation exposure was more than a year before prosthetic rehabilitation. He also concluded that the number of remaining teeth and the type of denture has a minimal effect on QoL.

Discussion

Prosthodontic rehabilitation after partial mandibulectomy should enhance mastication and esthetics by retraining the mandibular muscles that remain post-resection. The rehabilitation depends on the integrity of the mandible, the status of the teeth and muscles of mastication, and adequate salivary flow [16]. The degree of resultant disability is often related to the resection of the anterior or posterior mandible or a combination of both along with its supporting structures. The prosthodontic rehabilitation will further be challenged by the presence of xerostomia, nerve paraesthesia, graft complications, the amount of mandibular deviation, the angular pathway of mandibular closure, and the effect of resultant occlusal offset forces [17, 18].

Surgical rehabilitation after hemimandibulectomy aims primarily to bridge the defects and manage the discontinuity of the mandible to improve the quality of life. Marginal resection of the mandible is less aggressive than segmental resection due to its more conservative approach that provided function, phonation, and esthetics at acceptable levels. These functions were highly compromised, especially with the food mixing ability when resection is accompanied by glossectomy [8, 11]. However, the perceived chewing ability, and OHRQoL were not accountable to the extent of surgical excision, thereby indicating the presence of other contributing factors that have to be taken into consideration [8]. Literature also suggests that the masticatory performance after segmental mandibulectomy with free flap surgery was on par with the presurgical score [14].

Improvement of quality of life after prosthetic rehabilitation requires adequate planning in the management of soft and hard tissue defects. Pre-prosthetic surgery such as vestibuloplasty, osteotomy, and distraction osteogenesis enabled ease of prosthetic rehabilitation. Bone augments with soft tissue management are essential before implant placement and prosthetic restoration [13]. Literature suggests that the functional outcomes and depression alleviation were better with the augmentation procedure using fibula-free flap during mandibular reconstruction thereby improving the overall QoL [19, 20]. In contrast, Van Gemert et al. [21] stated better QoL in the patients with reconstruction plates than the fibula graft. However, the fibula-free flap allows the placement of implants for dental rehabilitation which is not possible with reconstruction plates [12]. Management of hard and soft tissue defects with the surgical graft leads to excessive scar tissue formation that causes difficulty in retaining the guidance prosthesis. These complications obscure the planned prosthetic treatment and hence, the prosthodontic intervention should begin immediately after the surgical phase to prevent scar formation [22].

The review suggested an overall increase in the QoL on rehabilitation with acrylic prosthesis depicting satisfactory functionality with a considerable improvement in mastication, speech, and social life [9]. The improvement was more evident at 3 months than during the 2-week post-rehabilitation [9]. The lateral shift of the mandible in a hemimandibulectomy case is compensated by the broad occlusal table developed in the palatal portion of the maxillary arch on the unaffected side to position the residual fragment into the correct sagittal relationship thereby enhancing the stability of the prostheses and improving the masticatory performance. Guidance therapy in addition to other preventive measures not only restore the function but also improve the QoL of hemimandibulectomy patients [23]. However, psychological discomfort was most prevalent among the rehabilitated individuals because of their difficulty in getting adapted to the prosthesis [9]. According to Fierz et al. [10], prosthetic rehabilitation has limited influence on the improvement in QoL.

Osseointegrated implants after surgical resection and reconstruction of the mandible improve the functional rehabilitation and QoL for these patients [3, 12, 13]. Literature suggests that the QoL and Denture Satisfaction Index did not differ based on the number of implants in an implant overdenture prosthesis, but the chewing ability was improved [12, 13]. Implant-supported prostheses prevent bone loss compared with conventional dentures and offer the advantage of low force transmission. Implant-supported overdenture prosthesis requires only a lesser number of implants to stabilize the prosthesis and has the advantage of easy abutments maintenance [11, 12]. However, implants do decrease the strength of the bone, causing fractures either during or after implant placement in extremely resorbed mandibles, and hence a minimum of 10-mm vertical bone dimension is recommended for implant placement for rehabilitating these defects [10].

The Qol observed after prosthetic rehabilitation was significantly improved and were similar in both conventional and implant-supported prosthesis [10, 14]. The reason could be that the implant therapy can sometimes be more invasive with accompanied complications and demands longer treatment duration; which in turn will worsen the subjective perception of an otherwise positive treatment outcome [10, 14]. Both implant-supported overdenture and fixed prostheses showed improved functional and psychological satisfaction at a statistically significant level [11], but potential problems of plaque accumulation, peri-implant mucositis, peri-implantitis, and fracture or wear of the prosthesis may impair the quality of life [12, 14]. Kumar et al. [12] suggested that soft tissue management with subperiosteal dissection and denture-guided epithelial regeneration with a close maintenance regimen are the prime factors in rehabilitating these patients to prevent peri-implantitis and associated reduction in oral health index.

Literature proved a significant correlation between the number of natural teeth and improved QoL; an increase in the number of occlusal units was associated with better perceived chewing ability and objective masticatory function [8, 15]. However, the mean masticatory performance score on the non-defect side was lower than the performance of an average conventional complete denture [14]. The patient’s oral function, masticatory ability, esthetics, and overall oral competency were observed to decrease in patients after hemimandibulectomy. Depending on the quality of the graft and its uptake, the overall oral competence considerably increased in patients who opted to undergo surgical reconstruction. But, these patients often require functional and esthetic enhancement. Ease of tongue movements, absence of soft tissue grafting, and the presence of bone continuity after resection contribute to better recovery of speaking ability after the prosthodontic intervention. Intensive speech therapy is also required to improve speech significantly in patients with and without a prosthesis [24, 25].

Quality of life after prosthetic rehabilitation is apparently greater in patients who did not undergo radiation therapy [10–12, 15]. An implant-supported fixed prosthesis is superior to a mucosal-borne prosthesis after radiotherapy because the sensitive mucous membrane is less loaded/irritated thereby improving the overall quality of life [10]. Literature evidence also suggested a waiting period of 1 year for implant therapy following radiation [10, 12, 15]. Karayazgan et al. recommended a minimum of 5 years for implant placement after completion of radiotherapy to reduce the failure rate with implant therapy [11].

The selected studies were heterogenous due to the dissimilarity in the extent of surgical excision and the type of prosthesis, hence a quantitative synthesis could not be done in this review. Though the studies were heterogenous, there was no heterogeneity in outcome depicting an improved quality of life with limited surgical extension, conventional prosthesis with increased occlusal unit and non-radiated individual. The review revealed limited clinical trials were available in assessing the quality of life in post-partial mandibulectomy patients with various modalities of prosthetic treatment. Further clinical trials are required comparing the conventional, implant-supported fixed, and implant-retained overdenture prosthesis to evaluate the effectiveness in post-partial mandibulectomy individuals.

Conclusion

Restoration of the function, psychological comfort, and improvement in esthetics was significant in patients who underwent prosthetic rehabilitation. The QoL between conventional and implant prostheses was observed to be more similar, and the effect of remaining hard and soft tissue structures has a major influence on patient comfort signifying the influence of the extent of surgical excision.

Supplementary Information

Below is the link to the electronic supplementary material.

Funding

This was a self-funded study and there was no financial support from external organization.

Data Availability

The datasets collected during the study are available as supplementary file.

Declarations

Competing Interests

The authors declare that they have no competing interests.